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3350c3c68a
skia2/experimental/Intersection/Simplify.cpp
caryclark@google.com 3350c3c68a shape ops work in progress 
this fixes quad/line intersection

git-svn-id: http://skia.googlecode.com/svn/trunk@5277 2bbb7eff-a529-9590-31e7-b0007b416f81
2012-08-24 15:24:36 +00:00

3969 lines
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/*
* Copyright 2012 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "Simplify.h"
#undef SkASSERT
#define SkASSERT(cond) while (!(cond)) { sk_throw(); }
// Terminology:
// A Path contains one of more Contours
// A Contour is made up of Segment array
// A Segment is described by a Verb and a Point array with 2, 3, or 4 points
// A Verb is one of Line, Quad(ratic), or Cubic
// A Segment contains a Span array
// A Span is describes a portion of a Segment using starting and ending T
// T values range from 0 to 1, where 0 is the first Point in the Segment
// An Edge is a Segment generated from a Span
// FIXME: remove once debugging is complete
#ifdef SK_DEBUG
int gDebugMaxWindSum = SK_MaxS32;
int gDebugMaxWindValue = SK_MaxS32;
#endif
#define HIGH_DEF_ANGLES 1
#if HIGH_DEF_ANGLES
typedef double AngleValue;
#else
typedef SkScalar AngleValue;
#endif
#define DEBUG_UNUSED 0 // set to expose unused functions
#if 1 // set to 1 for multiple thread -- no debugging
const bool gRunTestsInOneThread = false;
#define DEBUG_ACTIVE_SPANS 0
#define DEBUG_ADD_INTERSECTING_TS 0
#define DEBUG_ADD_T_PAIR 0
#define DEBUG_ANGLE 0
#define DEBUG_CONCIDENT 0
#define DEBUG_CROSS 0
#define DEBUG_DUMP 0
#define DEBUG_MARK_DONE 0
#define DEBUG_PATH_CONSTRUCTION 0
#define DEBUG_SORT 0
#define DEBUG_WIND_BUMP 0
#define DEBUG_WINDING 0
#else
const bool gRunTestsInOneThread = true;
#define DEBUG_ACTIVE_SPANS 1
#define DEBUG_ADD_INTERSECTING_TS 0
#define DEBUG_ADD_T_PAIR 0
#define DEBUG_ANGLE 1
#define DEBUG_CONCIDENT 1
#define DEBUG_CROSS 0
#define DEBUG_DUMP 1
#define DEBUG_MARK_DONE 1
#define DEBUG_PATH_CONSTRUCTION 1
#define DEBUG_SORT 1
#define DEBUG_WIND_BUMP 0
#define DEBUG_WINDING 1
#endif
#if (DEBUG_ACTIVE_SPANS || DEBUG_CONCIDENT || DEBUG_SORT) && !DEBUG_DUMP
#undef DEBUG_DUMP
#define DEBUG_DUMP 1
#endif
#if DEBUG_DUMP
static const char* kLVerbStr[] = {"", "line", "quad", "cubic"};
// static const char* kUVerbStr[] = {"", "Line", "Quad", "Cubic"};
static int gContourID;
static int gSegmentID;
#endif
#ifndef DEBUG_TEST
#define DEBUG_TEST 0
#endif
static int LineIntersect(const SkPoint a[2], const SkPoint b[2],
Intersections& intersections) {
const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
const _Line bLine = {{b[0].fX, b[0].fY}, {b[1].fX, b[1].fY}};
return intersect(aLine, bLine, intersections.fT[0], intersections.fT[1]);
}
static int QuadLineIntersect(const SkPoint a[3], const SkPoint b[2],
Intersections& intersections) {
const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
const _Line bLine = {{b[0].fX, b[0].fY}, {b[1].fX, b[1].fY}};
return intersect(aQuad, bLine, intersections);
}
static int CubicLineIntersect(const SkPoint a[2], const SkPoint b[3],
Intersections& intersections) {
const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
{a[3].fX, a[3].fY}};
const _Line bLine = {{b[0].fX, b[0].fY}, {b[1].fX, b[1].fY}};
return intersect(aCubic, bLine, intersections.fT[0], intersections.fT[1]);
}
static int QuadIntersect(const SkPoint a[3], const SkPoint b[3],
Intersections& intersections) {
const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
const Quadratic bQuad = {{b[0].fX, b[0].fY}, {b[1].fX, b[1].fY}, {b[2].fX, b[2].fY}};
intersect(aQuad, bQuad, intersections);
return intersections.fUsed;
}
static int CubicIntersect(const SkPoint a[4], const SkPoint b[4],
Intersections& intersections) {
const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
{a[3].fX, a[3].fY}};
const Cubic bCubic = {{b[0].fX, b[0].fY}, {b[1].fX, b[1].fY}, {b[2].fX, b[2].fY},
{b[3].fX, b[3].fY}};
intersect(aCubic, bCubic, intersections);
return intersections.fUsed;
}
static int HLineIntersect(const SkPoint a[2], SkScalar left, SkScalar right,
SkScalar y, bool flipped, Intersections& intersections) {
const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
return horizontalIntersect(aLine, left, right, y, flipped, intersections);
}
static int HQuadIntersect(const SkPoint a[3], SkScalar left, SkScalar right,
SkScalar y, bool flipped, Intersections& intersections) {
const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
return horizontalIntersect(aQuad, left, right, y, flipped, intersections);
}
static int HCubicIntersect(const SkPoint a[4], SkScalar left, SkScalar right,
SkScalar y, bool flipped, Intersections& intersections) {
const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
{a[3].fX, a[3].fY}};
return horizontalIntersect(aCubic, left, right, y, flipped, intersections);
}
static int VLineIntersect(const SkPoint a[2], SkScalar top, SkScalar bottom,
SkScalar x, bool flipped, Intersections& intersections) {
const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
return verticalIntersect(aLine, top, bottom, x, flipped, intersections);
}
static int VQuadIntersect(const SkPoint a[3], SkScalar top, SkScalar bottom,
SkScalar x, bool flipped, Intersections& intersections) {
const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
return verticalIntersect(aQuad, top, bottom, x, flipped, intersections);
}
static int VCubicIntersect(const SkPoint a[4], SkScalar top, SkScalar bottom,
SkScalar x, bool flipped, Intersections& intersections) {
const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
{a[3].fX, a[3].fY}};
return verticalIntersect(aCubic, top, bottom, x, flipped, intersections);
}
static int (* const VSegmentIntersect[])(const SkPoint [], SkScalar ,
SkScalar , SkScalar , bool , Intersections& ) = {
NULL,
VLineIntersect,
VQuadIntersect,
VCubicIntersect
};
static void LineXYAtT(const SkPoint a[2], double t, SkPoint* out) {
const _Line line = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
double x, y;
xy_at_t(line, t, x, y);
out->fX = SkDoubleToScalar(x);
out->fY = SkDoubleToScalar(y);
}
static void QuadXYAtT(const SkPoint a[3], double t, SkPoint* out) {
const Quadratic quad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
double x, y;
xy_at_t(quad, t, x, y);
out->fX = SkDoubleToScalar(x);
out->fY = SkDoubleToScalar(y);
}
static void CubicXYAtT(const SkPoint a[4], double t, SkPoint* out) {
const Cubic cubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
{a[3].fX, a[3].fY}};
double x, y;
xy_at_t(cubic, t, x, y);
out->fX = SkDoubleToScalar(x);
out->fY = SkDoubleToScalar(y);
}
static void (* const SegmentXYAtT[])(const SkPoint [], double , SkPoint* ) = {
NULL,
LineXYAtT,
QuadXYAtT,
CubicXYAtT
};
static SkScalar LineXAtT(const SkPoint a[2], double t) {
const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
double x;
xy_at_t(aLine, t, x, *(double*) 0);
return SkDoubleToScalar(x);
}
static SkScalar QuadXAtT(const SkPoint a[3], double t) {
const Quadratic quad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
double x;
xy_at_t(quad, t, x, *(double*) 0);
return SkDoubleToScalar(x);
}
static SkScalar CubicXAtT(const SkPoint a[4], double t) {
const Cubic cubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
{a[3].fX, a[3].fY}};
double x;
xy_at_t(cubic, t, x, *(double*) 0);
return SkDoubleToScalar(x);
}
static SkScalar (* const SegmentXAtT[])(const SkPoint [], double ) = {
NULL,
LineXAtT,
QuadXAtT,
CubicXAtT
};
static SkScalar LineYAtT(const SkPoint a[2], double t) {
const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
double y;
xy_at_t(aLine, t, *(double*) 0, y);
return SkDoubleToScalar(y);
}
static SkScalar QuadYAtT(const SkPoint a[3], double t) {
const Quadratic quad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
double y;
xy_at_t(quad, t, *(double*) 0, y);
return SkDoubleToScalar(y);
}
static SkScalar CubicYAtT(const SkPoint a[4], double t) {
const Cubic cubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
{a[3].fX, a[3].fY}};
double y;
xy_at_t(cubic, t, *(double*) 0, y);
return SkDoubleToScalar(y);
}
static SkScalar (* const SegmentYAtT[])(const SkPoint [], double ) = {
NULL,
LineYAtT,
QuadYAtT,
CubicYAtT
};
static SkScalar LineDXAtT(const SkPoint a[2], double ) {
return a[1].fX - a[0].fX;
}
static SkScalar QuadDXAtT(const SkPoint a[3], double t) {
const Quadratic quad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY}};
double x;
dxdy_at_t(quad, t, x, *(double*) 0);
return SkDoubleToScalar(x);
}
static SkScalar CubicDXAtT(const SkPoint a[4], double t) {
const Cubic cubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}, {a[2].fX, a[2].fY},
{a[3].fX, a[3].fY}};
double x;
dxdy_at_t(cubic, t, x, *(double*) 0);
return SkDoubleToScalar(x);
}
static SkScalar (* const SegmentDXAtT[])(const SkPoint [], double ) = {
NULL,
LineDXAtT,
QuadDXAtT,
CubicDXAtT
};
static void LineSubDivide(const SkPoint a[2], double startT, double endT,
SkPoint sub[2]) {
const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
_Line dst;
sub_divide(aLine, startT, endT, dst);
sub[0].fX = SkDoubleToScalar(dst[0].x);
sub[0].fY = SkDoubleToScalar(dst[0].y);
sub[1].fX = SkDoubleToScalar(dst[1].x);
sub[1].fY = SkDoubleToScalar(dst[1].y);
}
static void QuadSubDivide(const SkPoint a[3], double startT, double endT,
SkPoint sub[3]) {
const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}};
Quadratic dst;
sub_divide(aQuad, startT, endT, dst);
sub[0].fX = SkDoubleToScalar(dst[0].x);
sub[0].fY = SkDoubleToScalar(dst[0].y);
sub[1].fX = SkDoubleToScalar(dst[1].x);
sub[1].fY = SkDoubleToScalar(dst[1].y);
sub[2].fX = SkDoubleToScalar(dst[2].x);
sub[2].fY = SkDoubleToScalar(dst[2].y);
}
static void CubicSubDivide(const SkPoint a[4], double startT, double endT,
SkPoint sub[4]) {
const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}, {a[3].fX, a[3].fY}};
Cubic dst;
sub_divide(aCubic, startT, endT, dst);
sub[0].fX = SkDoubleToScalar(dst[0].x);
sub[0].fY = SkDoubleToScalar(dst[0].y);
sub[1].fX = SkDoubleToScalar(dst[1].x);
sub[1].fY = SkDoubleToScalar(dst[1].y);
sub[2].fX = SkDoubleToScalar(dst[2].x);
sub[2].fY = SkDoubleToScalar(dst[2].y);
sub[3].fX = SkDoubleToScalar(dst[3].x);
sub[3].fY = SkDoubleToScalar(dst[3].y);
}
static void (* const SegmentSubDivide[])(const SkPoint [], double , double ,
SkPoint []) = {
NULL,
LineSubDivide,
QuadSubDivide,
CubicSubDivide
};
static void LineSubDivideHD(const SkPoint a[2], double startT, double endT,
_Point sub[]) {
const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
_Line dst;
sub_divide(aLine, startT, endT, dst);
sub[0] = dst[0];
sub[1] = dst[1];
}
static void QuadSubDivideHD(const SkPoint a[3], double startT, double endT,
_Point sub[]) {
const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}};
Quadratic dst;
sub_divide(aQuad, startT, endT, dst);
sub[0] = dst[0];
sub[1] = dst[1];
sub[2] = dst[2];
}
static void CubicSubDivideHD(const SkPoint a[4], double startT, double endT,
_Point sub[]) {
const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}, {a[3].fX, a[3].fY}};
Cubic dst;
sub_divide(aCubic, startT, endT, dst);
sub[0] = dst[0];
sub[1] = dst[1];
sub[2] = dst[2];
sub[3] = dst[3];
}
static void (* const SegmentSubDivideHD[])(const SkPoint [], double , double ,
_Point [] ) = {
NULL,
LineSubDivideHD,
QuadSubDivideHD,
CubicSubDivideHD
};
#if DEBUG_UNUSED
static void QuadSubBounds(const SkPoint a[3], double startT, double endT,
SkRect& bounds) {
SkPoint dst[3];
QuadSubDivide(a, startT, endT, dst);
bounds.fLeft = bounds.fRight = dst[0].fX;
bounds.fTop = bounds.fBottom = dst[0].fY;
for (int index = 1; index < 3; ++index) {
bounds.growToInclude(dst[index].fX, dst[index].fY);
}
}
static void CubicSubBounds(const SkPoint a[4], double startT, double endT,
SkRect& bounds) {
SkPoint dst[4];
CubicSubDivide(a, startT, endT, dst);
bounds.fLeft = bounds.fRight = dst[0].fX;
bounds.fTop = bounds.fBottom = dst[0].fY;
for (int index = 1; index < 4; ++index) {
bounds.growToInclude(dst[index].fX, dst[index].fY);
}
}
#endif
static SkPath::Verb QuadReduceOrder(const SkPoint a[3],
SkTDArray<SkPoint>& reducePts) {
const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}};
Quadratic dst;
int order = reduceOrder(aQuad, dst);
if (order == 2) { // quad became line
for (int index = 0; index < order; ++index) {
SkPoint* pt = reducePts.append();
pt->fX = SkDoubleToScalar(dst[index].x);
pt->fY = SkDoubleToScalar(dst[index].y);
}
}
return (SkPath::Verb) (order - 1);
}
static SkPath::Verb CubicReduceOrder(const SkPoint a[4],
SkTDArray<SkPoint>& reducePts) {
const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}, {a[3].fX, a[3].fY}};
Cubic dst;
int order = reduceOrder(aCubic, dst, kReduceOrder_QuadraticsAllowed);
if (order == 2 || order == 3) { // cubic became line or quad
for (int index = 0; index < order; ++index) {
SkPoint* pt = reducePts.append();
pt->fX = SkDoubleToScalar(dst[index].x);
pt->fY = SkDoubleToScalar(dst[index].y);
}
}
return (SkPath::Verb) (order - 1);
}
static bool QuadIsLinear(const SkPoint a[3]) {
const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}};
return isLinear(aQuad, 0, 2);
}
static bool CubicIsLinear(const SkPoint a[4]) {
const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}, {a[3].fX, a[3].fY}};
return isLinear(aCubic, 0, 3);
}
static SkScalar LineLeftMost(const SkPoint a[2], double startT, double endT) {
const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
double x[2];
xy_at_t(aLine, startT, x[0], *(double*) 0);
xy_at_t(aLine, endT, x[1], *(double*) 0);
return SkMinScalar((float) x[0], (float) x[1]);
}
static SkScalar QuadLeftMost(const SkPoint a[3], double startT, double endT) {
const Quadratic aQuad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}};
return (float) leftMostT(aQuad, startT, endT);
}
static SkScalar CubicLeftMost(const SkPoint a[4], double startT, double endT) {
const Cubic aCubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}, {a[3].fX, a[3].fY}};
return (float) leftMostT(aCubic, startT, endT);
}
static SkScalar (* const SegmentLeftMost[])(const SkPoint [], double , double) = {
NULL,
LineLeftMost,
QuadLeftMost,
CubicLeftMost
};
#if DEBUG_UNUSED
static bool IsCoincident(const SkPoint a[2], const SkPoint& above,
const SkPoint& below) {
const _Line aLine = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY}};
const _Line bLine = {{above.fX, above.fY}, {below.fX, below.fY}};
return implicit_matches_ulps(aLine, bLine, 32);
}
#endif
class Segment;
// sorting angles
// given angles of {dx dy ddx ddy dddx dddy} sort them
class Angle {
public:
// FIXME: this is bogus for quads and cubics
// if the quads and cubics' line from end pt to ctrl pt are coincident,
// there's no obvious way to determine the curve ordering from the
// derivatives alone. In particular, if one quadratic's coincident tangent
// is longer than the other curve, the final control point can place the
// longer curve on either side of the shorter one.
// Using Bezier curve focus http://cagd.cs.byu.edu/~tom/papers/bezclip.pdf
// may provide some help, but nothing has been figured out yet.
bool operator<(const Angle& rh) const {
if ((fDy < 0) ^ (rh.fDy < 0)) {
return fDy < 0;
}
if (fDy == 0 && rh.fDy == 0 && fDx * rh.fDx < 0) {
return fDx < rh.fDx;
}
AngleValue cmp = fDx * rh.fDy - rh.fDx * fDy;
if (!approximately_zero(cmp)) {
return cmp < 0;
}
AngleValue dy = approximately_pin(fDy + fDDy);
AngleValue rdy = approximately_pin(rh.fDy + rh.fDDy);
if (dy * rdy < 0) {
return dy < 0;
}
AngleValue dx = approximately_pin(fDx + fDDx);
AngleValue rdx = approximately_pin(rh.fDx + rh.fDDx);
if (dy == 0 && rdy == 0 && dx * rdx < 0) {
return dx < rdx;
}
cmp = dx * rdy - rdx * dy;
if (!approximately_zero(cmp)) {
return cmp < 0;
}
dy = approximately_pin(dy + fDDDy);
rdy = approximately_pin(rdy + rh.fDDDy);
if (dy * rdy < 0) {
return dy < 0;
}
dx = approximately_pin(dx + fDDDx);
rdx = approximately_pin(rdx + rh.fDDDx);
if (dy == 0 && rdy == 0 && dx * rdx < 0) {
return dx < rdx;
}
return dx * rdy < rdx * dy;
}
double dx() const {
return fDx;
}
double dy() const {
return fDy;
}
int end() const {
return fEnd;
}
bool isHorizontal() const {
return fDy == 0 && fDDy == 0 && fDDDy == 0;
}
// high precision version
#if HIGH_DEF_ANGLES
void set(const SkPoint* orig, SkPath::Verb verb, const Segment* segment,
int start, int end, double startT, double endT) {
Cubic pts;
(*SegmentSubDivideHD[verb])(orig, startT, endT, pts);
fSegment = segment;
fStart = start;
fEnd = end;
fDx = approximately_pin(pts[1].x - pts[0].x); // b - a
fDy = approximately_pin(pts[1].y - pts[0].y);
if (verb == SkPath::kLine_Verb) {
fDDx = fDDy = fDDDx = fDDDy = 0;
return;
}
fDDx = approximately_pin(pts[2].x - pts[1].x - fDx); // a - 2b + c
fDDy = approximately_pin(pts[2].y - pts[1].y - fDy);
if (verb == SkPath::kQuad_Verb) {
fDDDx = fDDDy = 0;
return;
}
fDDDx = approximately_pin(pts[3].x + 3 * (pts[1].x - pts[2].x) - pts[0].x);
fDDDy = approximately_pin(pts[3].y + 3 * (pts[1].y - pts[2].y) - pts[0].y);
}
#else
// since all angles share a point, this needs to know which point
// is the common origin, i.e., whether the center is at pts[0] or pts[verb]
// practically, this should only be called by addAngle
void set(const SkPoint* pts, SkPath::Verb verb, const Segment* segment,
int start, int end) {
SkASSERT(start != end);
fSegment = segment;
fStart = start;
fEnd = end;
fDx = approximately_pin(pts[1].fX - pts[0].fX); // b - a
fDy = approximately_pin(pts[1].fY - pts[0].fY);
if (verb == SkPath::kLine_Verb) {
fDDx = fDDy = fDDDx = fDDDy = 0;
return;
}
fDDx = approximately_pin(pts[2].fX - pts[1].fX - fDx); // a - 2b + c
fDDy = approximately_pin(pts[2].fY - pts[1].fY - fDy);
if (verb == SkPath::kQuad_Verb) {
fDDDx = fDDDy = 0;
return;
}
fDDDx = approximately_pin(pts[3].fX + 3 * (pts[1].fX - pts[2].fX) - pts[0].fX);
fDDDy = approximately_pin(pts[3].fY + 3 * (pts[1].fY - pts[2].fY) - pts[0].fY);
}
// noncoincident quads/cubics may have the same initial angle
// as lines, so must sort by derivatives as well
// if flatness turns out to be a reasonable way to sort, use the below:
void setFlat(const SkPoint* pts, SkPath::Verb verb, Segment* segment,
int start, int end) {
fSegment = segment;
fStart = start;
fEnd = end;
fDx = pts[1].fX - pts[0].fX; // b - a
fDy = pts[1].fY - pts[0].fY;
if (verb == SkPath::kLine_Verb) {
fDDx = fDDy = fDDDx = fDDDy = 0;
return;
}
if (verb == SkPath::kQuad_Verb) {
int uplsX = FloatAsInt(pts[2].fX - pts[1].fY - fDx);
int uplsY = FloatAsInt(pts[2].fY - pts[1].fY - fDy);
int larger = std::max(abs(uplsX), abs(uplsY));
int shift = 0;
double flatT;
SkPoint ddPt; // FIXME: get rid of copy (change fDD_ to point)
LineParameters implicitLine;
_Line tangent = {{pts[0].fX, pts[0].fY}, {pts[1].fX, pts[1].fY}};
implicitLine.lineEndPoints(tangent);
implicitLine.normalize();
while (larger > UlpsEpsilon * 1024) {
larger >>= 2;
++shift;
flatT = 0.5 / (1 << shift);
QuadXYAtT(pts, flatT, &ddPt);
_Point _pt = {ddPt.fX, ddPt.fY};
double distance = implicitLine.pointDistance(_pt);
if (approximately_zero(distance)) {
SkDebugf("%s ulps too small %1.9g\n", __FUNCTION__, distance);
break;
}
}
flatT = 0.5 / (1 << shift);
QuadXYAtT(pts, flatT, &ddPt);
fDDx = ddPt.fX - pts[0].fX;
fDDy = ddPt.fY - pts[0].fY;
SkASSERT(fDDx != 0 || fDDy != 0);
fDDDx = fDDDy = 0;
return;
}
SkASSERT(0); // FIXME: add cubic case
}
#endif
Segment* segment() const {
return const_cast<Segment*>(fSegment);
}
int sign() const {
return SkSign32(fStart - fEnd);
}
int start() const {
return fStart;
}
#if DEBUG_ANGLE
void debugShow(const SkPoint& a) const {
SkDebugf(" d=(%1.9g,%1.9g) dd=(%1.9g,%1.9g) ddd=(%1.9g,%1.9g)\n",
fDx, fDy, fDDx, fDDy, fDDDx, fDDDy);
AngleValue ax = (AngleValue) a.fX;
AngleValue ay = (AngleValue) a.fY;
AngleValue bx, by, cx, cy, dx, dy;
bx = ax + fDx; // add b - a
by = ay + fDy;
cx = ax + 2 * fDx + fDDx; // add a + 2(b - a) to a - 2b + c
cy = ay + 2 * fDy + fDDy;
if (fDDDx == 0 && fDDDy == 0) {
if (fDDx == 0 && fDDy == 0) {
SkDebugf(
" {SkPath::kLine_Verb, {{%1.9g, %1.9g}, {%1.9g, %1.9g} }},\n",
ax, ay, bx, by);
} else {
SkDebugf(
" {SkPath::kQuad_Verb, {{%1.9g, %1.9g}, {%1.9g, %1.9g}, {%1.9g, %1.9g}}},\n",
ax, ay, bx, by, cx, cy);
}
} else {
dx = fDDDx - ax - 3 * (cx - bx);
dy = fDDDy - ay - 3 * (cy - by);
SkDebugf(
" {SkPath::kCubic_Verb, {{%1.9g, %1.9g}, {%1.9g, %1.9g}, {%1.9g, %1.9g}, {%1.9g, %1.9g}}},\n",
ax, ay, bx, by, cx, cy, dx, dy);
}
}
#endif
private:
AngleValue fDx;
AngleValue fDy;
AngleValue fDDx;
AngleValue fDDy;
AngleValue fDDDx;
AngleValue fDDDy;
const Segment* fSegment;
int fStart;
int fEnd;
};
static void sortAngles(SkTDArray<Angle>& angles, SkTDArray<Angle*>& angleList) {
int angleCount = angles.count();
int angleIndex;
angleList.setReserve(angleCount);
for (angleIndex = 0; angleIndex < angleCount; ++angleIndex) {
*angleList.append() = &angles[angleIndex];
}
QSort<Angle>(angleList.begin(), angleList.end() - 1);
}
// Bounds, unlike Rect, does not consider a line to be empty.
struct Bounds : public SkRect {
static bool Intersects(const Bounds& a, const Bounds& b) {
return a.fLeft <= b.fRight && b.fLeft <= a.fRight &&
a.fTop <= b.fBottom && b.fTop <= a.fBottom;
}
void add(SkScalar left, SkScalar top, SkScalar right, SkScalar bottom) {
if (left < fLeft) {
fLeft = left;
}
if (top < fTop) {
fTop = top;
}
if (right > fRight) {
fRight = right;
}
if (bottom > fBottom) {
fBottom = bottom;
}
}
void add(const Bounds& toAdd) {
add(toAdd.fLeft, toAdd.fTop, toAdd.fRight, toAdd.fBottom);
}
bool isEmpty() {
return fLeft > fRight || fTop > fBottom
|| fLeft == fRight && fTop == fBottom
|| isnan(fLeft) || isnan(fRight)
|| isnan(fTop) || isnan(fBottom);
}
void setCubicBounds(const SkPoint a[4]) {
_Rect dRect;
Cubic cubic = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}, {a[3].fX, a[3].fY}};
dRect.setBounds(cubic);
set((float) dRect.left, (float) dRect.top, (float) dRect.right,
(float) dRect.bottom);
}
void setQuadBounds(const SkPoint a[3]) {
const Quadratic quad = {{a[0].fX, a[0].fY}, {a[1].fX, a[1].fY},
{a[2].fX, a[2].fY}};
_Rect dRect;
dRect.setBounds(quad);
set((float) dRect.left, (float) dRect.top, (float) dRect.right,
(float) dRect.bottom);
}
};
static bool useInnerWinding(int outerWinding, int innerWinding) {
SkASSERT(outerWinding != innerWinding);
int absOut = abs(outerWinding);
int absIn = abs(innerWinding);
bool result = absOut == absIn ? outerWinding < 0 : absOut < absIn;
if (outerWinding * innerWinding < 0) {
#if DEBUG_WINDING
SkDebugf("%s outer=%d inner=%d result=%s\n", __FUNCTION__,
outerWinding, innerWinding, result ? "true" : "false");
#endif
}
return result;
}
struct Span {
Segment* fOther;
mutable SkPoint fPt; // lazily computed as needed
double fT;
double fOtherT; // value at fOther[fOtherIndex].fT
int fOtherIndex; // can't be used during intersection
int fWindSum; // accumulated from contours surrounding this one
int fWindValue; // 0 == canceled; 1 == normal; >1 == coincident
bool fDone; // if set, this span to next higher T has been processed
};
class Segment {
public:
Segment() {
#if DEBUG_DUMP
fID = ++gSegmentID;
#endif
}
bool activeAngle(int index, int& done, SkTDArray<Angle>& angles) const {
if (activeAngleInner(index, done, angles)) {
return true;
}
double referenceT = fTs[index].fT;
int lesser = index;
while (--lesser >= 0 && approximately_negative(referenceT - fTs[lesser].fT)) {
if (activeAngleOther(lesser, done, angles)) {
return true;
}
}
do {
if (activeAngleOther(index, done, angles)) {
return true;
}
} while (++index < fTs.count() && approximately_negative(fTs[index].fT - referenceT));
return false;
}
bool activeAngleOther(int index, int& done, SkTDArray<Angle>& angles) const {
Span* span = &fTs[index];
Segment* other = span->fOther;
int oIndex = span->fOtherIndex;
return other->activeAngleInner(oIndex, done, angles);
}
bool activeAngleInner(int index, int& done, SkTDArray<Angle>& angles) const {
int next = nextSpan(index, 1);
if (next > 0) {
const Span& upSpan = fTs[index];
if (upSpan.fWindValue) {
addAngle(angles, index, next);
if (upSpan.fDone) {
done++;
} else if (upSpan.fWindSum != SK_MinS32) {
return true;
}
}
}
int prev = nextSpan(index, -1);
// edge leading into junction
if (prev >= 0) {
const Span& downSpan = fTs[prev];
if (downSpan.fWindValue) {
addAngle(angles, index, prev);
if (downSpan.fDone) {
done++;
} else if (downSpan.fWindSum != SK_MinS32) {
return true;
}
}
}
return false;
}
SkScalar activeTop() const {
SkASSERT(!done());
int count = fTs.count();
SkScalar result = SK_ScalarMax;
bool lastDone = true;
for (int index = 0; index < count; ++index) {
bool done = fTs[index].fDone;
if (!done || !lastDone) {
SkScalar y = yAtT(index);
if (result > y) {
result = y;
}
}
lastDone = done;
}
SkASSERT(result < SK_ScalarMax);
return result;
}
void addAngle(SkTDArray<Angle>& angles, int start, int end) const {
SkASSERT(start != end);
Angle* angle = angles.append();
#if HIGH_DEF_ANGLES==0 // old way
SkPoint edge[4];
(*SegmentSubDivide[fVerb])(fPts, fTs[start].fT, fTs[end].fT, edge);
angle->set(edge, fVerb, this, start, end);
#else // new way : compute temp edge in higher precision
angle->set(fPts, fVerb, this, start, end, fTs[start].fT, fTs[end].fT);
#endif
}
void addCancelOutsides(double tStart, double oStart, Segment& other,
double oEnd) {
int tIndex = -1;
int tCount = fTs.count();
int oIndex = -1;
int oCount = other.fTs.count();
do {
++tIndex;
} while (!approximately_negative(tStart - fTs[tIndex].fT) && tIndex < tCount);
int tIndexStart = tIndex;
do {
++oIndex;
} while (!approximately_negative(oStart - other.fTs[oIndex].fT) && oIndex < oCount);
int oIndexStart = oIndex;
double nextT;
do {
nextT = fTs[++tIndex].fT;
} while (nextT < 1 && approximately_negative(nextT - tStart));
double oNextT;
do {
oNextT = other.fTs[++oIndex].fT;
} while (oNextT < 1 && approximately_negative(oNextT - oStart));
// at this point, spans before and after are at:
// fTs[tIndexStart - 1], fTs[tIndexStart], fTs[tIndex]
// if tIndexStart == 0, no prior span
// if nextT == 1, no following span
// advance the span with zero winding
// if the following span exists (not past the end, non-zero winding)
// connect the two edges
if (!fTs[tIndexStart].fWindValue) {
if (tIndexStart > 0 && fTs[tIndexStart - 1].fWindValue) {
#if DEBUG_CONCIDENT
SkDebugf("%s 1 this=%d other=%d t [%d] %1.9g (%1.9g,%1.9g)\n",
__FUNCTION__, fID, other.fID, tIndexStart - 1,
fTs[tIndexStart].fT, xyAtT(tIndexStart).fX,
xyAtT(tIndexStart).fY);
#endif
addTPair(fTs[tIndexStart].fT, other, other.fTs[oIndex].fT, false);
}
if (nextT < 1 && fTs[tIndex].fWindValue) {
#if DEBUG_CONCIDENT
SkDebugf("%s 2 this=%d other=%d t [%d] %1.9g (%1.9g,%1.9g)\n",
__FUNCTION__, fID, other.fID, tIndex,
fTs[tIndex].fT, xyAtT(tIndex).fX,
xyAtT(tIndex).fY);
#endif
addTPair(fTs[tIndex].fT, other, other.fTs[oIndexStart].fT, false);
}
} else {
SkASSERT(!other.fTs[oIndexStart].fWindValue);
if (oIndexStart > 0 && other.fTs[oIndexStart - 1].fWindValue) {
#if DEBUG_CONCIDENT
SkDebugf("%s 3 this=%d other=%d t [%d] %1.9g (%1.9g,%1.9g)\n",
__FUNCTION__, fID, other.fID, oIndexStart - 1,
other.fTs[oIndexStart].fT, other.xyAtT(oIndexStart).fX,
other.xyAtT(oIndexStart).fY);
other.debugAddTPair(other.fTs[oIndexStart].fT, *this, fTs[tIndex].fT);
#endif
}
if (oNextT < 1 && other.fTs[oIndex].fWindValue) {
#if DEBUG_CONCIDENT
SkDebugf("%s 4 this=%d other=%d t [%d] %1.9g (%1.9g,%1.9g)\n",
__FUNCTION__, fID, other.fID, oIndex,
other.fTs[oIndex].fT, other.xyAtT(oIndex).fX,
other.xyAtT(oIndex).fY);
other.debugAddTPair(other.fTs[oIndex].fT, *this, fTs[tIndexStart].fT);
#endif
}
}
}
void addCoinOutsides(const SkTDArray<double>& outsideTs, Segment& other,
double oEnd) {
// walk this to outsideTs[0]
// walk other to outsideTs[1]
// if either is > 0, add a pointer to the other, copying adjacent winding
int tIndex = -1;
int oIndex = -1;
double tStart = outsideTs[0];
double oStart = outsideTs[1];
do {
++tIndex;
} while (!approximately_negative(tStart - fTs[tIndex].fT));
do {
++oIndex;
} while (!approximately_negative(oStart - other.fTs[oIndex].fT));
if (tIndex > 0 || oIndex > 0) {
addTPair(tStart, other, oStart, false);
}
tStart = fTs[tIndex].fT;
oStart = other.fTs[oIndex].fT;
do {
double nextT;
do {
nextT = fTs[++tIndex].fT;
} while (approximately_negative(nextT - tStart));
tStart = nextT;
do {
nextT = other.fTs[++oIndex].fT;
} while (approximately_negative(nextT - oStart));
oStart = nextT;
if (tStart == 1 && oStart == 1) {
break;
}
addTPair(tStart, other, oStart, false);
} while (tStart < 1 && oStart < 1 && !approximately_negative(oEnd - oStart));
}
void addCubic(const SkPoint pts[4]) {
init(pts, SkPath::kCubic_Verb);
fBounds.setCubicBounds(pts);
}
// FIXME: this needs to defer add for aligned consecutive line segments
SkPoint addCurveTo(int start, int end, SkPath& path, bool active) {
SkPoint edge[4];
// OPTIMIZE? if not active, skip remainder and return xy_at_t(end)
(*SegmentSubDivide[fVerb])(fPts, fTs[start].fT, fTs[end].fT, edge);
if (active) {
#if DEBUG_PATH_CONSTRUCTION
SkDebugf("%s %s (%1.9g,%1.9g)", __FUNCTION__,
kLVerbStr[fVerb], edge[1].fX, edge[1].fY);
if (fVerb > 1) {
SkDebugf(" (%1.9g,%1.9g)", edge[2].fX, edge[2].fY);
}
if (fVerb > 2) {
SkDebugf(" (%1.9g,%1.9g)", edge[3].fX, edge[3].fY);
}
SkDebugf("\n");
#endif
switch (fVerb) {
case SkPath::kLine_Verb:
path.lineTo(edge[1].fX, edge[1].fY);
break;
case SkPath::kQuad_Verb:
path.quadTo(edge[1].fX, edge[1].fY, edge[2].fX, edge[2].fY);
break;
case SkPath::kCubic_Verb:
path.cubicTo(edge[1].fX, edge[1].fY, edge[2].fX, edge[2].fY,
edge[3].fX, edge[3].fY);
break;
}
}
return edge[fVerb];
}
void addLine(const SkPoint pts[2]) {
init(pts, SkPath::kLine_Verb);
fBounds.set(pts, 2);
}
const SkPoint& addMoveTo(int tIndex, SkPath& path, bool active) {
const SkPoint& pt = xyAtT(tIndex);
if (active) {
#if DEBUG_PATH_CONSTRUCTION
SkDebugf("%s (%1.9g,%1.9g)\n", __FUNCTION__, pt.fX, pt.fY);
#endif
path.moveTo(pt.fX, pt.fY);
}
return pt;
}
// add 2 to edge or out of range values to get T extremes
void addOtherT(int index, double otherT, int otherIndex) {
Span& span = fTs[index];
span.fOtherT = otherT;
span.fOtherIndex = otherIndex;
}
void addQuad(const SkPoint pts[3]) {
init(pts, SkPath::kQuad_Verb);
fBounds.setQuadBounds(pts);
}
// Defer all coincident edge processing until
// after normal intersections have been computed
// no need to be tricky; insert in normal T order
// resolve overlapping ts when considering coincidence later
// add non-coincident intersection. Resulting edges are sorted in T.
int addT(double newT, Segment* other) {
// FIXME: in the pathological case where there is a ton of intercepts,
// binary search?
int insertedAt = -1;
size_t tCount = fTs.count();
// FIXME: only do this pinning here (e.g. this is done also in quad/line intersect)
if (approximately_less_than_zero(newT)) {
newT = 0;
}
if (approximately_greater_than_one(newT)) {
newT = 1;
}
for (size_t index = 0; index < tCount; ++index) {
// OPTIMIZATION: if there are three or more identical Ts, then
// the fourth and following could be further insertion-sorted so
// that all the edges are clockwise or counterclockwise.
// This could later limit segment tests to the two adjacent
// neighbors, although it doesn't help with determining which
// circular direction to go in.
if (newT < fTs[index].fT) {
insertedAt = index;
break;
}
}
Span* span;
if (insertedAt >= 0) {
span = fTs.insert(insertedAt);
} else {
insertedAt = tCount;
span = fTs.append();
}
span->fT = newT;
span->fOther = other;
span->fPt.fX = SK_ScalarNaN;
span->fWindSum = SK_MinS32;
span->fWindValue = 1;
if ((span->fDone = newT == 1)) {
++fDoneSpans;
}
return insertedAt;
}
// set spans from start to end to decrement by one
// note this walks other backwards
// FIMXE: there's probably an edge case that can be constructed where
// two span in one segment are separated by float epsilon on one span but
// not the other, if one segment is very small. For this
// case the counts asserted below may or may not be enough to separate the
// spans. Even if the counts work out, what if the spans aren't correctly
// sorted? It feels better in such a case to match the span's other span
// pointer since both coincident segments must contain the same spans.
void addTCancel(double startT, double endT, Segment& other,
double oStartT, double oEndT) {
SkASSERT(!approximately_negative(endT - startT));
SkASSERT(!approximately_negative(oEndT - oStartT));
int index = 0;
while (!approximately_negative(startT - fTs[index].fT)) {
++index;
}
int oIndex = other.fTs.count();
while (approximately_positive(other.fTs[--oIndex].fT - oEndT))
;
double tRatio = (oEndT - oStartT) / (endT - startT);
Span* test = &fTs[index];
Span* oTest = &other.fTs[oIndex];
SkTDArray<double> outsideTs;
SkTDArray<double> oOutsideTs;
do {
bool decrement = test->fWindValue && oTest->fWindValue;
bool track = test->fWindValue || oTest->fWindValue;
double testT = test->fT;
double oTestT = oTest->fT;
Span* span = test;
do {
if (decrement) {
decrementSpan(span);
} else if (track && span->fT < 1 && oTestT < 1) {
TrackOutside(outsideTs, span->fT, oTestT);
}
span = &fTs[++index];
} while (approximately_negative(span->fT - testT));
Span* oSpan = oTest;
double otherTMatchStart = oEndT - (span->fT - startT) * tRatio;
double otherTMatchEnd = oEndT - (test->fT - startT) * tRatio;
SkDEBUGCODE(int originalWindValue = oSpan->fWindValue);
while (approximately_negative(otherTMatchStart - oSpan->fT)
&& !approximately_negative(otherTMatchEnd - oSpan->fT)) {
#ifdef SK_DEBUG
SkASSERT(originalWindValue == oSpan->fWindValue);
#endif
if (decrement) {
other.decrementSpan(oSpan);
} else if (track && oSpan->fT < 1 && testT < 1) {
TrackOutside(oOutsideTs, oSpan->fT, testT);
}
if (!oIndex) {
break;
}
oSpan = &other.fTs[--oIndex];
}
test = span;
oTest = oSpan;
} while (!approximately_negative(endT - test->fT));
SkASSERT(!oIndex || approximately_negative(oTest->fT - oStartT));
// FIXME: determine if canceled edges need outside ts added
if (!done() && outsideTs.count()) {
double tStart = outsideTs[0];
double oStart = outsideTs[1];
addCancelOutsides(tStart, oStart, other, oEndT);
int count = outsideTs.count();
if (count > 2) {
double tStart = outsideTs[count - 2];
double oStart = outsideTs[count - 1];
addCancelOutsides(tStart, oStart, other, oEndT);
}
}
if (!other.done() && oOutsideTs.count()) {
double tStart = oOutsideTs[0];
double oStart = oOutsideTs[1];
other.addCancelOutsides(tStart, oStart, *this, endT);
}
}
// set spans from start to end to increment the greater by one and decrement
// the lesser
void addTCoincident(const int xorMask, double startT, double endT, Segment& other,
double oStartT, double oEndT) {
SkASSERT(!approximately_negative(endT - startT));
SkASSERT(!approximately_negative(oEndT - oStartT));
int index = 0;
while (!approximately_negative(startT - fTs[index].fT)) {
++index;
}
int oIndex = 0;
while (!approximately_negative(oStartT - other.fTs[oIndex].fT)) {
++oIndex;
}
double tRatio = (oEndT - oStartT) / (endT - startT);
Span* test = &fTs[index];
Span* oTest = &other.fTs[oIndex];
SkTDArray<double> outsideTs;
SkTDArray<double> xOutsideTs;
SkTDArray<double> oOutsideTs;
SkTDArray<double> oxOutsideTs;
do {
bool transfer = test->fWindValue && oTest->fWindValue;
bool winding = xorMask < 0;
bool decrementThis = (test->fWindValue < oTest->fWindValue) & winding;
bool decrementOther = (test->fWindValue >= oTest->fWindValue) & winding;
Span* end = test;
double startT = end->fT;
int startIndex = index;
double oStartT = oTest->fT;
int oStartIndex = oIndex;
do {
if (transfer) {
if (decrementOther) {
#ifdef SK_DEBUG
SkASSERT(abs(end->fWindValue) < gDebugMaxWindValue);
#endif
++(end->fWindValue);
} else if (decrementSpan(end)) {
TrackOutside(outsideTs, end->fT, oStartT);
}
} else if (oTest->fWindValue) {
SkASSERT(!decrementOther);
if (startIndex > 0 && fTs[startIndex - 1].fWindValue) {
TrackOutside(xOutsideTs, end->fT, oStartT);
}
}
end = &fTs[++index];
} while (approximately_negative(end->fT - test->fT));
// because of the order in which coincidences are resolved, this and other
// may not have the same intermediate points. Compute the corresponding
// intermediate T values (using this as the master, other as the follower)
// and walk other conditionally -- hoping that it catches up in the end
double otherTMatch = (test->fT - startT) * tRatio + oStartT;
Span* oEnd = oTest;
while (!approximately_negative(oEndT - oEnd->fT) && approximately_negative(oEnd->fT - otherTMatch)) {
if (transfer) {
if (decrementThis) {
#ifdef SK_DEBUG
SkASSERT(abs(oEnd->fWindValue) < gDebugMaxWindValue);
#endif
++(oEnd->fWindValue);
} else if (other.decrementSpan(oEnd)) {
TrackOutside(oOutsideTs, oEnd->fT, startT);
}
} else if (test->fWindValue) {
SkASSERT(!decrementOther);
if (oStartIndex > 0 && other.fTs[oStartIndex - 1].fWindValue) {
SkASSERT(0); // track for later?
}
}
oEnd = &other.fTs[++oIndex];
}
test = end;
oTest = oEnd;
} while (!approximately_negative(endT - test->fT));
SkASSERT(approximately_negative(oTest->fT - oEndT));
SkASSERT(approximately_negative(oEndT - oTest->fT));
if (!done()) {
if (outsideTs.count()) {
addCoinOutsides(outsideTs, other, oEndT);
}
if (xOutsideTs.count()) {
addCoinOutsides(xOutsideTs, other, oEndT);
}
}
if (!other.done() && oOutsideTs.count()) {
other.addCoinOutsides(oOutsideTs, *this, endT);
}
}
// FIXME: this doesn't prevent the same span from being added twice
// fix in caller, assert here?
void addTPair(double t, Segment& other, double otherT, bool borrowWind) {
int tCount = fTs.count();
for (int tIndex = 0; tIndex < tCount; ++tIndex) {
const Span& span = fTs[tIndex];
if (!approximately_negative(span.fT - t)) {
break;
}
if (approximately_negative(span.fT - t) && span.fOther == &other && span.fOtherT == otherT) {
#if DEBUG_ADD_T_PAIR
SkDebugf("%s addTPair duplicate this=%d %1.9g other=%d %1.9g\n",
__FUNCTION__, fID, t, other.fID, otherT);
#endif
return;
}
}
#if DEBUG_ADD_T_PAIR
SkDebugf("%s addTPair this=%d %1.9g other=%d %1.9g\n",
__FUNCTION__, fID, t, other.fID, otherT);
#endif
int insertedAt = addT(t, &other);
int otherInsertedAt = other.addT(otherT, this);
addOtherT(insertedAt, otherT, otherInsertedAt);
other.addOtherT(otherInsertedAt, t, insertedAt);
matchWindingValue(insertedAt, t, borrowWind);
other.matchWindingValue(otherInsertedAt, otherT, borrowWind);
}
void addTwoAngles(int start, int end, SkTDArray<Angle>& angles) const {
// add edge leading into junction
if (fTs[SkMin32(end, start)].fWindValue > 0) {
addAngle(angles, end, start);
}
// add edge leading away from junction
int step = SkSign32(end - start);
int tIndex = nextSpan(end, step);
if (tIndex >= 0 && fTs[SkMin32(end, tIndex)].fWindValue > 0) {
addAngle(angles, end, tIndex);
}
}
const Bounds& bounds() const {
return fBounds;
}
void buildAngles(int index, SkTDArray<Angle>& angles) const {
double referenceT = fTs[index].fT;
int lesser = index;
while (--lesser >= 0 && approximately_negative(referenceT - fTs[lesser].fT)) {
buildAnglesInner(lesser, angles);
}
do {
buildAnglesInner(index, angles);
} while (++index < fTs.count() && approximately_negative(fTs[index].fT - referenceT));
}
void buildAnglesInner(int index, SkTDArray<Angle>& angles) const {
Span* span = &fTs[index];
Segment* other = span->fOther;
// if there is only one live crossing, and no coincidence, continue
// in the same direction
// if there is coincidence, the only choice may be to reverse direction
// find edge on either side of intersection
int oIndex = span->fOtherIndex;
// if done == -1, prior span has already been processed
int step = 1;
int next = other->nextSpan(oIndex, step);
if (next < 0) {
step = -step;
next = other->nextSpan(oIndex, step);
}
// add candidate into and away from junction
other->addTwoAngles(next, oIndex, angles);
}
bool cancels(const Segment& other) const {
SkASSERT(fVerb == SkPath::kLine_Verb);
SkASSERT(other.fVerb == SkPath::kLine_Verb);
SkPoint dxy = fPts[0] - fPts[1];
SkPoint odxy = other.fPts[0] - other.fPts[1];
return dxy.fX * odxy.fX < 0 || dxy.fY * odxy.fY < 0;
}
// figure out if the segment's ascending T goes clockwise or not
// not enough context to write this as shown
// instead, add all segments meeting at the top
// sort them using buildAngleList
// find the first in the sort
// see if ascendingT goes to top
bool clockwise(int /* tIndex */) const {
SkASSERT(0); // incomplete
return false;
}
int computeSum(int startIndex, int endIndex) {
SkTDArray<Angle> angles;
addTwoAngles(startIndex, endIndex, angles);
buildAngles(endIndex, angles);
SkTDArray<Angle*> sorted;
sortAngles(angles, sorted);
#if DEBUG_SORT
sorted[0]->segment()->debugShowSort(__FUNCTION__, sorted, 0, 0);
#endif
int angleCount = angles.count();
const Angle* angle;
const Segment* base;
int winding;
int firstIndex = 0;
do {
angle = sorted[firstIndex];
base = angle->segment();
winding = base->windSum(angle);
if (winding != SK_MinS32) {
break;
}
if (++firstIndex == angleCount) {
return SK_MinS32;
}
} while (true);
// turn winding into contourWinding
int spanWinding = base->spanSign(angle);
bool inner = useInnerWinding(winding + spanWinding, winding);
#if DEBUG_WINDING
SkDebugf("%s spanWinding=%d winding=%d sign=%d inner=%d result=%d\n", __FUNCTION__,
spanWinding, winding, angle->sign(), inner,
inner ? winding + spanWinding : winding);
#endif
if (inner) {
winding += spanWinding;
}
#if DEBUG_SORT
base->debugShowSort(__FUNCTION__, sorted, firstIndex, winding);
#endif
int nextIndex = firstIndex + 1;
int lastIndex = firstIndex != 0 ? firstIndex : angleCount;
winding -= base->spanSign(angle);
do {
if (nextIndex == angleCount) {
nextIndex = 0;
}
angle = sorted[nextIndex];
Segment* segment = angle->segment();
int maxWinding = winding;
winding -= segment->spanSign(angle);
if (segment->windSum(angle) == SK_MinS32) {
if (useInnerWinding(maxWinding, winding)) {
maxWinding = winding;
}
segment->markAndChaseWinding(angle, maxWinding);
}
} while (++nextIndex != lastIndex);
return windSum(SkMin32(startIndex, endIndex));
}
int crossedSpan(const SkPoint& basePt, SkScalar& bestY, double& hitT) const {
int bestT = -1;
SkScalar top = bounds().fTop;
SkScalar bottom = bounds().fBottom;
int end = 0;
do {
int start = end;
end = nextSpan(start, 1);
if (fTs[start].fWindValue == 0) {
continue;
}
SkPoint edge[4];
// OPTIMIZE: wrap this so that if start==0 end==fTCount-1 we can
// work with the original data directly
double startT = fTs[start].fT;
double endT = fTs[end].fT;
(*SegmentSubDivide[fVerb])(fPts, startT, endT, edge);
// intersect ray starting at basePt with edge
Intersections intersections;
int pts = (*VSegmentIntersect[fVerb])(edge, top, bottom, basePt.fX,
false, intersections);
if (pts == 0) {
continue;
}
if (pts > 1 && fVerb == SkPath::kLine_Verb) {
// if the intersection is edge on, wait for another one
continue;
}
SkASSERT(pts == 1); // FIXME: more code required to disambiguate
SkPoint pt;
double foundT = intersections.fT[0][0];
double testT = startT + (endT - startT) * foundT;
(*SegmentXYAtT[fVerb])(fPts, testT, &pt);
if (bestY < pt.fY && pt.fY < basePt.fY) {
bestY = pt.fY;
bestT = foundT < 1 ? start : end;
hitT = testT;
}
} while (fTs[end].fT != 1);
return bestT;
}
bool crossedSpanHalves(const SkPoint& basePt, bool leftHalf, bool rightHalf) {
// if a segment is connected to this one, consider it crossing
int tIndex;
if (fPts[0].fX == basePt.fX) {
tIndex = 0;
do {
const Span& sSpan = fTs[tIndex];
const Segment* sOther = sSpan.fOther;
if (!sOther->fTs[sSpan.fOtherIndex].fWindValue) {
continue;
}
if (leftHalf ? sOther->fBounds.fLeft < basePt.fX
: sOther->fBounds.fRight > basePt.fX) {
return true;
}
} while (fTs[++tIndex].fT == 0);
}
if (fPts[fVerb].fX == basePt.fX) {
tIndex = fTs.count() - 1;
do {
const Span& eSpan = fTs[tIndex];
const Segment* eOther = eSpan.fOther;
if (!eOther->fTs[eSpan.fOtherIndex].fWindValue) {
continue;
}
if (leftHalf ? eOther->fBounds.fLeft < basePt.fX
: eOther->fBounds.fRight > basePt.fX) {
return true;
}
} while (fTs[--tIndex].fT == 1);
}
return false;
}
bool decrementSpan(Span* span) {
SkASSERT(span->fWindValue > 0);
if (--(span->fWindValue) == 0) {
span->fDone = true;
++fDoneSpans;
return true;
}
return false;
}
bool done() const {
SkASSERT(fDoneSpans <= fTs.count());
return fDoneSpans == fTs.count();
}
bool done(const Angle& angle) const {
int start = angle.start();
int end = angle.end();
const Span& mSpan = fTs[SkMin32(start, end)];
return mSpan.fDone;
}
// so the span needs to contain the pairing info found here
// this should include the winding computed for the edge, and
// what edge it connects to, and whether it is discarded
// (maybe discarded == abs(winding) > 1) ?
// only need derivatives for duration of sorting, add a new struct
// for pairings, remove extra spans that have zero length and
// reference an unused other
// for coincident, the last span on the other may be marked done
// (always?)
// if loop is exhausted, contour may be closed.
// FIXME: pass in close point so we can check for closure
// given a segment, and a sense of where 'inside' is, return the next
// segment. If this segment has an intersection, or ends in multiple
// segments, find the mate that continues the outside.
// note that if there are multiples, but no coincidence, we can limit
// choices to connections in the correct direction
// mark found segments as done
// start is the index of the beginning T of this edge
// it is guaranteed to have an end which describes a non-zero length (?)
// winding -1 means ccw, 1 means cw
Segment* findNextWinding(SkTDArray<Span*>& chase, bool active,
int& nextStart, int& nextEnd, int& winding, int& spanWinding) {
const int startIndex = nextStart;
const int endIndex = nextEnd;
int outerWinding = winding;
int innerWinding = winding + spanWinding;
#if DEBUG_WINDING
SkDebugf("%s winding=%d spanWinding=%d outerWinding=%d innerWinding=%d\n",
__FUNCTION__, winding, spanWinding, outerWinding, innerWinding);
#endif
if (useInnerWinding(outerWinding, innerWinding)) {
outerWinding = innerWinding;
}
SkASSERT(startIndex != endIndex);
int count = fTs.count();
SkASSERT(startIndex < endIndex ? startIndex < count - 1
: startIndex > 0);
int step = SkSign32(endIndex - startIndex);
int end = nextSpan(startIndex, step);
SkASSERT(end >= 0);
Span* endSpan = &fTs[end];
Segment* other;
if (isSimple(end)) {
// mark the smaller of startIndex, endIndex done, and all adjacent
// spans with the same T value (but not 'other' spans)
#if DEBUG_WINDING
SkDebugf("%s simple\n", __FUNCTION__);
#endif
markDone(SkMin32(startIndex, endIndex), outerWinding);
other = endSpan->fOther;
nextStart = endSpan->fOtherIndex;
double startT = other->fTs[nextStart].fT;
nextEnd = nextStart;
do {
nextEnd += step;
} while (approximately_zero(startT - other->fTs[nextEnd].fT));
SkASSERT(step < 0 ? nextEnd >= 0 : nextEnd < other->fTs.count());
return other;
}
// more than one viable candidate -- measure angles to find best
SkTDArray<Angle> angles;
SkASSERT(startIndex - endIndex != 0);
SkASSERT((startIndex - endIndex < 0) ^ (step < 0));
addTwoAngles(startIndex, end, angles);
buildAngles(end, angles);
SkTDArray<Angle*> sorted;
sortAngles(angles, sorted);
int angleCount = angles.count();
int firstIndex = findStartingEdge(sorted, startIndex, end);
SkASSERT(firstIndex >= 0);
#if DEBUG_SORT
debugShowSort(__FUNCTION__, sorted, firstIndex, winding);
#endif
SkASSERT(sorted[firstIndex]->segment() == this);
#if DEBUG_WINDING
SkDebugf("%s [%d] sign=%d\n", __FUNCTION__, firstIndex, sorted[firstIndex]->sign());
#endif
int sumWinding = winding - spanSign(sorted[firstIndex]);
int nextIndex = firstIndex + 1;
int lastIndex = firstIndex != 0 ? firstIndex : angleCount;
const Angle* foundAngle = NULL;
// FIXME: found done logic probably fails if there are more than 4
// sorted angles. It should bias towards the first and last undone
// edges -- but not sure that it won't choose a middle (incorrect)
// edge if one is undone
bool foundDone = false;
bool foundDone2 = false;
// iterate through the angle, and compute everyone's winding
bool altFlipped = false;
bool foundFlipped = false;
int foundMax = SK_MinS32;
int foundSum = SK_MinS32;
Segment* nextSegment;
int lastNonZeroSum = winding;
do {
if (nextIndex == angleCount) {
nextIndex = 0;
}
const Angle* nextAngle = sorted[nextIndex];
int maxWinding = sumWinding;
if (sumWinding) {
lastNonZeroSum = sumWinding;
}
nextSegment = nextAngle->segment();
sumWinding -= nextSegment->spanSign(nextAngle);
altFlipped ^= lastNonZeroSum * sumWinding < 0; // flip if different signs
#if DEBUG_WINDING
SkASSERT(abs(sumWinding) <= gDebugMaxWindSum);
SkDebugf("%s [%d] maxWinding=%d sumWinding=%d sign=%d altFlipped=%d\n", __FUNCTION__,
nextIndex, maxWinding, sumWinding, nextAngle->sign(), altFlipped);
#endif
if (!sumWinding) {
if (!active) {
markDone(SkMin32(startIndex, endIndex), outerWinding);
// FIXME: seems like a bug that this isn't calling userInnerWinding
nextSegment->markWinding(SkMin32(nextAngle->start(),
nextAngle->end()), maxWinding);
#if DEBUG_WINDING
SkDebugf("%s [%d] inactive\n", __FUNCTION__, nextIndex);
#endif
return NULL;
}
if (!foundAngle || foundDone) {
foundAngle = nextAngle;
foundDone = nextSegment->done(*nextAngle);
foundFlipped = altFlipped;
foundMax = maxWinding;
}
continue;
}
if (!maxWinding && (!foundAngle || foundDone2)) {
#if DEBUG_WINDING
if (foundAngle && foundDone2) {
SkDebugf("%s [%d] !foundAngle && foundDone2\n", __FUNCTION__, nextIndex);
}
#endif
foundAngle = nextAngle;
foundDone2 = nextSegment->done(*nextAngle);
foundFlipped = altFlipped;
foundSum = sumWinding;
}
if (nextSegment->done()) {
continue;
}
// if the winding is non-zero, nextAngle does not connect to
// current chain. If we haven't done so already, mark the angle
// as done, record the winding value, and mark connected unambiguous
// segments as well.
if (nextSegment->windSum(nextAngle) == SK_MinS32) {
if (useInnerWinding(maxWinding, sumWinding)) {
maxWinding = sumWinding;
}
Span* last;
if (foundAngle) {
last = nextSegment->markAndChaseWinding(nextAngle, maxWinding);
} else {
last = nextSegment->markAndChaseDone(nextAngle, maxWinding);
}
if (last) {
*chase.append() = last;
}
}
} while (++nextIndex != lastIndex);
markDone(SkMin32(startIndex, endIndex), outerWinding);
if (!foundAngle) {
return NULL;
}
nextStart = foundAngle->start();
nextEnd = foundAngle->end();
nextSegment = foundAngle->segment();
int flipped = foundFlipped ? -1 : 1;
spanWinding = SkSign32(spanWinding) * flipped * nextSegment->windValue(
SkMin32(nextStart, nextEnd));
if (winding) {
#if DEBUG_WINDING
SkDebugf("%s ---6 winding=%d foundSum=", __FUNCTION__, winding);
if (foundSum == SK_MinS32) {
SkDebugf("?");
} else {
SkDebugf("%d", foundSum);
}
SkDebugf(" foundMax=");
if (foundMax == SK_MinS32) {
SkDebugf("?");
} else {
SkDebugf("%d", foundMax);
}
SkDebugf("\n");
#endif
winding = foundSum;
}
#if DEBUG_WINDING
SkDebugf("%s spanWinding=%d flipped=%d\n", __FUNCTION__, spanWinding, flipped);
#endif
return nextSegment;
}
Segment* findNextXor(int& nextStart, int& nextEnd) {
const int startIndex = nextStart;
const int endIndex = nextEnd;
SkASSERT(startIndex != endIndex);
int count = fTs.count();
SkASSERT(startIndex < endIndex ? startIndex < count - 1
: startIndex > 0);
int step = SkSign32(endIndex - startIndex);
int end = nextSpan(startIndex, step);
SkASSERT(end >= 0);
Span* endSpan = &fTs[end];
Segment* other;
markDone(SkMin32(startIndex, endIndex), 1);
if (isSimple(end)) {
#if DEBUG_WINDING
SkDebugf("%s simple\n", __FUNCTION__);
#endif
other = endSpan->fOther;
nextStart = endSpan->fOtherIndex;
double startT = other->fTs[nextStart].fT;
SkDEBUGCODE(bool firstLoop = true;)
if ((approximately_less_than_zero(startT) && step < 0)
|| (approximately_greater_than_one(startT) && step > 0)) {
step = -step;
SkDEBUGCODE(firstLoop = false;)
}
do {
nextEnd = nextStart;
do {
nextEnd += step;
} while (approximately_zero(startT - other->fTs[nextEnd].fT));
if (other->fTs[SkMin32(nextStart, nextEnd)].fWindValue) {
break;
}
#ifdef SK_DEBUG
SkASSERT(firstLoop);
#endif
SkDEBUGCODE(firstLoop = false;)
step = -step;
} while (true);
SkASSERT(step < 0 ? nextEnd >= 0 : nextEnd < other->fTs.count());
return other;
}
SkTDArray<Angle> angles;
SkASSERT(startIndex - endIndex != 0);
SkASSERT((startIndex - endIndex < 0) ^ (step < 0));
addTwoAngles(startIndex, end, angles);
buildAngles(end, angles);
SkTDArray<Angle*> sorted;
sortAngles(angles, sorted);
int angleCount = angles.count();
int firstIndex = findStartingEdge(sorted, startIndex, end);
SkASSERT(firstIndex >= 0);
#if DEBUG_SORT
debugShowSort(__FUNCTION__, sorted, firstIndex, 0);
#endif
SkASSERT(sorted[firstIndex]->segment() == this);
int nextIndex = firstIndex + 1;
int lastIndex = firstIndex != 0 ? firstIndex : angleCount;
const Angle* nextAngle;
Segment* nextSegment;
do {
if (nextIndex == angleCount) {
nextIndex = 0;
}
nextAngle = sorted[nextIndex];
nextSegment = nextAngle->segment();
if (!nextSegment->done(*nextAngle)) {
break;
}
if (++nextIndex == lastIndex) {
return NULL;
}
} while (true);
nextStart = nextAngle->start();
nextEnd = nextAngle->end();
return nextSegment;
}
int findStartingEdge(SkTDArray<Angle*>& sorted, int start, int end) {
int angleCount = sorted.count();
int firstIndex = -1;
for (int angleIndex = 0; angleIndex < angleCount; ++angleIndex) {
const Angle* angle = sorted[angleIndex];
if (angle->segment() == this && angle->start() == end &&
angle->end() == start) {
firstIndex = angleIndex;
break;
}
}
return firstIndex;
}
// FIXME: this is tricky code; needs its own unit test
void findTooCloseToCall(int xorMask) {
int count = fTs.count();
if (count < 3) { // require t=0, x, 1 at minimum
return;
}
int matchIndex = 0;
int moCount;
Span* match;
Segment* mOther;
do {
match = &fTs[matchIndex];
mOther = match->fOther;
// FIXME: allow quads, cubics to be near coincident?
if (mOther->fVerb == SkPath::kLine_Verb) {
moCount = mOther->fTs.count();
if (moCount >= 3) {
break;
}
}
if (++matchIndex >= count) {
return;
}
} while (true); // require t=0, x, 1 at minimum
// OPTIMIZATION: defer matchPt until qualifying toCount is found?
const SkPoint* matchPt = &xyAtT(match);
// look for a pair of nearby T values that map to the same (x,y) value
// if found, see if the pair of other segments share a common point. If
// so, the span from here to there is coincident.
for (int index = matchIndex + 1; index < count; ++index) {
Span* test = &fTs[index];
if (test->fDone) {
continue;
}
Segment* tOther = test->fOther;
if (tOther->fVerb != SkPath::kLine_Verb) {
continue; // FIXME: allow quads, cubics to be near coincident?
}
int toCount = tOther->fTs.count();
if (toCount < 3) { // require t=0, x, 1 at minimum
continue;
}
const SkPoint* testPt = &xyAtT(test);
if (*matchPt != *testPt) {
matchIndex = index;
moCount = toCount;
match = test;
mOther = tOther;
matchPt = testPt;
continue;
}
int moStart = -1;
int moEnd = -1;
double moStartT, moEndT;
for (int moIndex = 0; moIndex < moCount; ++moIndex) {
Span& moSpan = mOther->fTs[moIndex];
if (moSpan.fDone) {
continue;
}
if (moSpan.fOther == this) {
if (moSpan.fOtherT == match->fT) {
moStart = moIndex;
moStartT = moSpan.fT;
}
continue;
}
if (moSpan.fOther == tOther) {
if (tOther->fTs[moSpan.fOtherIndex].fWindValue == 0) {
moStart = -1;
break;
}
SkASSERT(moEnd == -1);
moEnd = moIndex;
moEndT = moSpan.fT;
}
}
if (moStart < 0 || moEnd < 0) {
continue;
}
// FIXME: if moStartT, moEndT are initialized to NaN, can skip this test
if (approximately_equal(moStartT, moEndT)) {
continue;
}
int toStart = -1;
int toEnd = -1;
double toStartT, toEndT;
for (int toIndex = 0; toIndex < toCount; ++toIndex) {
Span& toSpan = tOther->fTs[toIndex];
if (toSpan.fDone) {
continue;
}
if (toSpan.fOther == this) {
if (toSpan.fOtherT == test->fT) {
toStart = toIndex;
toStartT = toSpan.fT;
}
continue;
}
if (toSpan.fOther == mOther && toSpan.fOtherT == moEndT) {
if (mOther->fTs[toSpan.fOtherIndex].fWindValue == 0) {
moStart = -1;
break;
}
SkASSERT(toEnd == -1);
toEnd = toIndex;
toEndT = toSpan.fT;
}
}
// FIXME: if toStartT, toEndT are initialized to NaN, can skip this test
if (toStart <= 0 || toEnd <= 0) {
continue;
}
if (approximately_equal(toStartT, toEndT)) {
continue;
}
// test to see if the segment between there and here is linear
if (!mOther->isLinear(moStart, moEnd)
|| !tOther->isLinear(toStart, toEnd)) {
continue;
}
bool flipped = (moStart - moEnd) * (toStart - toEnd) < 1;
if (flipped) {
mOther->addTCancel(moStartT, moEndT, *tOther, toEndT, toStartT);
} else {
mOther->addTCoincident(xorMask, moStartT, moEndT, *tOther, toStartT, toEndT);
}
}
}
// OPTIMIZATION : for a pair of lines, can we compute points at T (cached)
// and use more concise logic like the old edge walker code?
// FIXME: this needs to deal with coincident edges
Segment* findTop(int& tIndex, int& endIndex) {
// iterate through T intersections and return topmost
// topmost tangent from y-min to first pt is closer to horizontal
SkASSERT(!done());
int firstT;
int lastT;
SkPoint topPt;
topPt.fY = SK_ScalarMax;
int count = fTs.count();
// see if either end is not done since we want smaller Y of the pair
bool lastDone = true;
for (int index = 0; index < count; ++index) {
const Span& span = fTs[index];
if (!span.fDone || !lastDone) {
const SkPoint& intercept = xyAtT(&span);
if (topPt.fY > intercept.fY || (topPt.fY == intercept.fY
&& topPt.fX > intercept.fX)) {
topPt = intercept;
firstT = lastT = index;
} else if (topPt == intercept) {
lastT = index;
}
}
lastDone = span.fDone;
}
// sort the edges to find the leftmost
int step = 1;
int end = nextSpan(firstT, step);
if (end == -1) {
step = -1;
end = nextSpan(firstT, step);
SkASSERT(end != -1);
}
// if the topmost T is not on end, or is three-way or more, find left
// look for left-ness from tLeft to firstT (matching y of other)
SkTDArray<Angle> angles;
SkASSERT(firstT - end != 0);
addTwoAngles(end, firstT, angles);
buildAngles(firstT, angles);
SkTDArray<Angle*> sorted;
sortAngles(angles, sorted);
#if DEBUG_SORT
sorted[0]->segment()->debugShowSort(__FUNCTION__, sorted, 0, 0);
#endif
// skip edges that have already been processed
firstT = -1;
Segment* leftSegment;
do {
const Angle* angle = sorted[++firstT];
leftSegment = angle->segment();
tIndex = angle->end();
endIndex = angle->start();
} while (leftSegment->fTs[SkMin32(tIndex, endIndex)].fDone);
return leftSegment;
}
// FIXME: not crazy about this
// when the intersections are performed, the other index is into an
// incomplete array. as the array grows, the indices become incorrect
// while the following fixes the indices up again, it isn't smart about
// skipping segments whose indices are already correct
// assuming we leave the code that wrote the index in the first place
void fixOtherTIndex() {
int iCount = fTs.count();
for (int i = 0; i < iCount; ++i) {
Span& iSpan = fTs[i];
double oT = iSpan.fOtherT;
Segment* other = iSpan.fOther;
int oCount = other->fTs.count();
for (int o = 0; o < oCount; ++o) {
Span& oSpan = other->fTs[o];
if (oT == oSpan.fT && this == oSpan.fOther) {
iSpan.fOtherIndex = o;
break;
}
}
}
}
// OPTIMIZATION: uses tail recursion. Unwise?
Span* innerChaseDone(int index, int step, int winding) {
int end = nextSpan(index, step);
SkASSERT(end >= 0);
if (multipleSpans(end)) {
return &fTs[end];
}
const Span& endSpan = fTs[end];
Segment* other = endSpan.fOther;
index = endSpan.fOtherIndex;
int otherEnd = other->nextSpan(index, step);
Span* last = other->innerChaseDone(index, step, winding);
other->markDone(SkMin32(index, otherEnd), winding);
return last;
}
Span* innerChaseWinding(int index, int step, int winding) {
int end = nextSpan(index, step);
SkASSERT(end >= 0);
if (multipleSpans(end)) {
return &fTs[end];
}
const Span& endSpan = fTs[end];
Segment* other = endSpan.fOther;
index = endSpan.fOtherIndex;
int otherEnd = other->nextSpan(index, step);
int min = SkMin32(index, otherEnd);
if (other->fTs[min].fWindSum != SK_MinS32) {
SkASSERT(other->fTs[min].fWindSum == winding);
return NULL;
}
Span* last = other->innerChaseWinding(index, step, winding);
other->markWinding(min, winding);
return last;
}
void init(const SkPoint pts[], SkPath::Verb verb) {
fPts = pts;
fVerb = verb;
fDoneSpans = 0;
}
bool intersected() const {
return fTs.count() > 0;
}
bool isConnected(int startIndex, int endIndex) const {
return fTs[startIndex].fWindSum != SK_MinS32
|| fTs[endIndex].fWindSum != SK_MinS32;
}
bool isLinear(int start, int end) const {
if (fVerb == SkPath::kLine_Verb) {
return true;
}
if (fVerb == SkPath::kQuad_Verb) {
SkPoint qPart[3];
QuadSubDivide(fPts, fTs[start].fT, fTs[end].fT, qPart);
return QuadIsLinear(qPart);
} else {
SkASSERT(fVerb == SkPath::kCubic_Verb);
SkPoint cPart[4];
CubicSubDivide(fPts, fTs[start].fT, fTs[end].fT, cPart);
return CubicIsLinear(cPart);
}
}
// OPTIMIZE: successive calls could start were the last leaves off
// or calls could specialize to walk forwards or backwards
bool isMissing(double startT) const {
size_t tCount = fTs.count();
for (size_t index = 0; index < tCount; ++index) {
if (approximately_zero(startT - fTs[index].fT)) {
return false;
}
}
return true;
}
bool isSimple(int end) const {
int count = fTs.count();
if (count == 2) {
return true;
}
double t = fTs[end].fT;
if (approximately_less_than_zero(t)) {
return !approximately_less_than_zero(fTs[1].fT);
}
if (approximately_greater_than_one(t)) {
return !approximately_greater_than_one(fTs[count - 2].fT);
}
return false;
}
bool isHorizontal() const {
return fBounds.fTop == fBounds.fBottom;
}
bool isVertical() const {
return fBounds.fLeft == fBounds.fRight;
}
SkScalar leftMost(int start, int end) const {
return (*SegmentLeftMost[fVerb])(fPts, fTs[start].fT, fTs[end].fT);
}
// this span is excluded by the winding rule -- chase the ends
// as long as they are unambiguous to mark connections as done
// and give them the same winding value
Span* markAndChaseDone(const Angle* angle, int winding) {
int index = angle->start();
int endIndex = angle->end();
int step = SkSign32(endIndex - index);
Span* last = innerChaseDone(index, step, winding);
markDone(SkMin32(index, endIndex), winding);
return last;
}
Span* markAndChaseWinding(const Angle* angle, int winding) {
int index = angle->start();
int endIndex = angle->end();
int min = SkMin32(index, endIndex);
int step = SkSign32(endIndex - index);
Span* last = innerChaseWinding(index, step, winding);
markWinding(min, winding);
return last;
}
// FIXME: this should also mark spans with equal (x,y)
// This may be called when the segment is already marked done. While this
// wastes time, it shouldn't do any more than spin through the T spans.
// OPTIMIZATION: abort on first done found (assuming that this code is
// always called to mark segments done).
void markDone(int index, int winding) {
// SkASSERT(!done());
SkASSERT(winding);
double referenceT = fTs[index].fT;
int lesser = index;
while (--lesser >= 0 && approximately_negative(referenceT - fTs[lesser].fT)) {
markOneDone(__FUNCTION__, lesser, winding);
}
do {
markOneDone(__FUNCTION__, index, winding);
} while (++index < fTs.count() && approximately_negative(fTs[index].fT - referenceT));
}
void markOneDone(const char* funName, int tIndex, int winding) {
Span* span = markOneWinding(funName, tIndex, winding);
if (!span) {
return;
}
span->fDone = true;
fDoneSpans++;
}
Span* markOneWinding(const char* funName, int tIndex, int winding) {
Span& span = fTs[tIndex];
if (span.fDone) {
return NULL;
}
#if DEBUG_MARK_DONE
debugShowNewWinding(funName, span, winding);
#endif
SkASSERT(span.fWindSum == SK_MinS32 || span.fWindSum == winding);
#ifdef SK_DEBUG
SkASSERT(abs(winding) <= gDebugMaxWindSum);
#endif
span.fWindSum = winding;
return &span;
}
void markWinding(int index, int winding) {
// SkASSERT(!done());
SkASSERT(winding);
double referenceT = fTs[index].fT;
int lesser = index;
while (--lesser >= 0 && approximately_negative(referenceT - fTs[lesser].fT)) {
markOneWinding(__FUNCTION__, lesser, winding);
}
do {
markOneWinding(__FUNCTION__, index, winding);
} while (++index < fTs.count() && approximately_negative(fTs[index].fT - referenceT));
}
void matchWindingValue(int tIndex, double t, bool borrowWind) {
int nextDoorWind = SK_MaxS32;
if (tIndex > 0) {
const Span& below = fTs[tIndex - 1];
if (approximately_negative(t - below.fT)) {
nextDoorWind = below.fWindValue;
}
}
if (nextDoorWind == SK_MaxS32 && tIndex + 1 < fTs.count()) {
const Span& above = fTs[tIndex + 1];
if (approximately_negative(above.fT - t)) {
nextDoorWind = above.fWindValue;
}
}
if (nextDoorWind == SK_MaxS32 && borrowWind && tIndex > 0 && t < 1) {
const Span& below = fTs[tIndex - 1];
nextDoorWind = below.fWindValue;
}
if (nextDoorWind != SK_MaxS32) {
Span& newSpan = fTs[tIndex];
newSpan.fWindValue = nextDoorWind;
if (!nextDoorWind) {
newSpan.fDone = true;
++fDoneSpans;
}
}
}
// return span if when chasing, two or more radiating spans are not done
// OPTIMIZATION: ? multiple spans is detected when there is only one valid
// candidate and the remaining spans have windValue == 0 (canceled by
// coincidence). The coincident edges could either be removed altogether,
// or this code could be more complicated in detecting this case. Worth it?
bool multipleSpans(int end) const {
return end > 0 && end < fTs.count() - 1;
}
// This has callers for two different situations: one establishes the end
// of the current span, and one establishes the beginning of the next span
// (thus the name). When this is looking for the end of the current span,
// coincidence is found when the beginning Ts contain -step and the end
// contains step. When it is looking for the beginning of the next, the
// first Ts found can be ignored and the last Ts should contain -step.
// OPTIMIZATION: probably should split into two functions
int nextSpan(int from, int step) const {
const Span& fromSpan = fTs[from];
int count = fTs.count();
int to = from;
while (step > 0 ? ++to < count : --to >= 0) {
const Span& span = fTs[to];
if (approximately_zero(span.fT - fromSpan.fT)) {
continue;
}
return to;
}
return -1;
}
const SkPoint* pts() const {
return fPts;
}
void reset() {
init(NULL, (SkPath::Verb) -1);
fBounds.set(SK_ScalarMax, SK_ScalarMax, SK_ScalarMax, SK_ScalarMax);
fTs.reset();
}
// OPTIMIZATION: mark as debugging only if used solely by tests
const Span& span(int tIndex) const {
return fTs[tIndex];
}
int spanSign(int startIndex, int endIndex) const {
int result = startIndex < endIndex ? -fTs[startIndex].fWindValue :
fTs[endIndex].fWindValue;
#if DEBUG_WIND_BUMP
SkDebugf("%s spanSign=%d\n", __FUNCTION__, result);
#endif
return result;
}
int spanSign(const Angle* angle) const {
SkASSERT(angle->segment() == this);
return spanSign(angle->start(), angle->end());
}
// OPTIMIZATION: mark as debugging only if used solely by tests
double t(int tIndex) const {
return fTs[tIndex].fT;
}
static void TrackOutside(SkTDArray<double>& outsideTs, double end,
double start) {
int outCount = outsideTs.count();
if (outCount == 0 || !approximately_negative(end - outsideTs[outCount - 2])) {
*outsideTs.append() = end;
*outsideTs.append() = start;
}
}
void undoneSpan(int& start, int& end) {
size_t tCount = fTs.count();
size_t index;
for (index = 0; index < tCount; ++index) {
if (!fTs[index].fDone) {
break;
}
}
SkASSERT(index < tCount - 1);
start = index;
double startT = fTs[index].fT;
while (approximately_negative(fTs[++index].fT - startT))
SkASSERT(index < tCount);
SkASSERT(index < tCount);
end = index;
}
void updatePts(const SkPoint pts[]) {
fPts = pts;
}
SkPath::Verb verb() const {
return fVerb;
}
int windSum(int tIndex) const {
return fTs[tIndex].fWindSum;
}
int windSum(const Angle* angle) const {
int start = angle->start();
int end = angle->end();
int index = SkMin32(start, end);
return windSum(index);
}
int windValue(int tIndex) const {
return fTs[tIndex].fWindValue;
}
int windValue(const Angle* angle) const {
int start = angle->start();
int end = angle->end();
int index = SkMin32(start, end);
return windValue(index);
}
SkScalar xAtT(const Span* span) const {
return xyAtT(span).fX;
}
const SkPoint& xyAtT(int index) const {
return xyAtT(&fTs[index]);
}
const SkPoint& xyAtT(const Span* span) const {
if (SkScalarIsNaN(span->fPt.fX)) {
if (span->fT == 0) {
span->fPt = fPts[0];
} else if (span->fT == 1) {
span->fPt = fPts[fVerb];
} else {
(*SegmentXYAtT[fVerb])(fPts, span->fT, &span->fPt);
}
}
return span->fPt;
}
SkScalar yAtT(int index) const {
return yAtT(&fTs[index]);
}
SkScalar yAtT(const Span* span) const {
return xyAtT(span).fY;
}
#if DEBUG_DUMP
void dump() const {
const char className[] = "Segment";
const int tab = 4;
for (int i = 0; i < fTs.count(); ++i) {
SkPoint out;
(*SegmentXYAtT[fVerb])(fPts, t(i), &out);
SkDebugf("%*s [%d] %s.fTs[%d]=%1.9g (%1.9g,%1.9g) other=%d"
" otherT=%1.9g windSum=%d\n",
tab + sizeof(className), className, fID,
kLVerbStr[fVerb], i, fTs[i].fT, out.fX, out.fY,
fTs[i].fOther->fID, fTs[i].fOtherT, fTs[i].fWindSum);
}
SkDebugf("%*s [%d] fBounds=(l:%1.9g, t:%1.9g r:%1.9g, b:%1.9g)",
tab + sizeof(className), className, fID,
fBounds.fLeft, fBounds.fTop, fBounds.fRight, fBounds.fBottom);
}
#endif
#if DEBUG_CONCIDENT
// assert if pair has not already been added
void debugAddTPair(double t, const Segment& other, double otherT) const {
for (int i = 0; i < fTs.count(); ++i) {
if (fTs[i].fT == t && fTs[i].fOther == &other && fTs[i].fOtherT == otherT) {
return;
}
}
SkASSERT(0);
}
#endif
#if DEBUG_DUMP
int debugID() const {
return fID;
}
#endif
#if DEBUG_WINDING
void debugShowSums() const {
SkDebugf("%s id=%d (%1.9g,%1.9g %1.9g,%1.9g)", __FUNCTION__, fID,
fPts[0].fX, fPts[0].fY, fPts[fVerb].fX, fPts[fVerb].fY);
for (int i = 0; i < fTs.count(); ++i) {
const Span& span = fTs[i];
SkDebugf(" [t=%1.3g %1.9g,%1.9g w=", span.fT, xAtT(&span), yAtT(&span));
if (span.fWindSum == SK_MinS32) {
SkDebugf("?");
} else {
SkDebugf("%d", span.fWindSum);
}
SkDebugf("]");
}
SkDebugf("\n");
}
#endif
#if DEBUG_CONCIDENT
void debugShowTs() const {
SkDebugf("%s id=%d", __FUNCTION__, fID);
for (int i = 0; i < fTs.count(); ++i) {
SkDebugf(" [o=%d t=%1.3g %1.9g,%1.9g w=%d]", fTs[i].fOther->fID,
fTs[i].fT, xAtT(&fTs[i]), yAtT(&fTs[i]), fTs[i].fWindValue);
}
SkDebugf("\n");
}
#endif
#if DEBUG_ACTIVE_SPANS
void debugShowActiveSpans() const {
if (done()) {
return;
}
for (int i = 0; i < fTs.count(); ++i) {
if (fTs[i].fDone) {
continue;
}
SkDebugf("%s id=%d", __FUNCTION__, fID);
SkDebugf(" (%1.9g,%1.9g", fPts[0].fX, fPts[0].fY);
for (int vIndex = 1; vIndex <= fVerb; ++vIndex) {
SkDebugf(" %1.9g,%1.9g", fPts[vIndex].fX, fPts[vIndex].fY);
}
const Span* span = &fTs[i];
SkDebugf(") t=%1.9g (%1.9g,%1.9g)", fTs[i].fT,
xAtT(span), yAtT(span));
const Segment* other = fTs[i].fOther;
SkDebugf(" other=%d otherT=%1.9g otherIndex=%d windSum=",
other->fID, fTs[i].fOtherT, fTs[i].fOtherIndex);
if (fTs[i].fWindSum == SK_MinS32) {
SkDebugf("?");
} else {
SkDebugf("%d", fTs[i].fWindSum);
}
SkDebugf(" windValue=%d\n", fTs[i].fWindValue);
}
}
#endif
#if DEBUG_MARK_DONE
void debugShowNewWinding(const char* fun, const Span& span, int winding) {
const SkPoint& pt = xyAtT(&span);
SkDebugf("%s id=%d", fun, fID);
SkDebugf(" (%1.9g,%1.9g", fPts[0].fX, fPts[0].fY);
for (int vIndex = 1; vIndex <= fVerb; ++vIndex) {
SkDebugf(" %1.9g,%1.9g", fPts[vIndex].fX, fPts[vIndex].fY);
}
SkDebugf(") t=%1.9g (%1.9g,%1.9g) newWindSum=%d windSum=",
span.fT, pt.fX, pt.fY, winding);
if (span.fWindSum == SK_MinS32) {
SkDebugf("?");
} else {
SkDebugf("%d", span.fWindSum);
}
SkDebugf(" windValue=%d\n", span.fWindValue);
}
#endif
#if DEBUG_SORT
void debugShowSort(const char* fun, const SkTDArray<Angle*>& angles, int first,
const int contourWinding) const {
SkASSERT(angles[first]->segment() == this);
SkASSERT(angles.count() > 1);
int lastSum = contourWinding;
int windSum = lastSum - spanSign(angles[first]);
SkDebugf("%s %s contourWinding=%d sign=%d\n", fun, __FUNCTION__,
contourWinding, spanSign(angles[first]));
int index = first;
bool firstTime = true;
do {
const Angle& angle = *angles[index];
const Segment& segment = *angle.segment();
int start = angle.start();
int end = angle.end();
const Span& sSpan = segment.fTs[start];
const Span& eSpan = segment.fTs[end];
const Span& mSpan = segment.fTs[SkMin32(start, end)];
if (!firstTime) {
lastSum = windSum;
windSum -= segment.spanSign(&angle);
}
SkDebugf("%s [%d] id=%d %s start=%d (%1.9g,%,1.9g) end=%d (%1.9g,%,1.9g)"
" sign=%d windValue=%d winding: %d->%d (max=%d) done=%d\n",
__FUNCTION__, index, segment.fID, kLVerbStr[segment.fVerb],
start, segment.xAtT(&sSpan),
segment.yAtT(&sSpan), end, segment.xAtT(&eSpan),
segment.yAtT(&eSpan), angle.sign(), mSpan.fWindValue,
lastSum, windSum, useInnerWinding(lastSum, windSum)
? windSum : lastSum, mSpan.fDone);
#if DEBUG_ANGLE
angle.debugShow(segment.xyAtT(&sSpan));
#endif
++index;
if (index == angles.count()) {
index = 0;
}
if (firstTime) {
firstTime = false;
}
} while (index != first);
}
#endif
#if DEBUG_WINDING
bool debugVerifyWinding(int start, int end, int winding) const {
const Span& span = fTs[SkMin32(start, end)];
int spanWinding = span.fWindSum;
if (spanWinding == SK_MinS32) {
return true;
}
int spanSign = SkSign32(start - end);
int signedVal = spanSign * span.fWindValue;
if (signedVal < 0) {
spanWinding -= signedVal;
}
return span.fWindSum == winding;
}
#endif
private:
const SkPoint* fPts;
SkPath::Verb fVerb;
Bounds fBounds;
SkTDArray<Span> fTs; // two or more (always includes t=0 t=1)
int fDoneSpans; // quick check that segment is finished
#if DEBUG_DUMP
int fID;
#endif
};
class Contour;
struct Coincidence {
Contour* fContours[2];
int fSegments[2];
double fTs[2][2];
};
class Contour {
public:
Contour() {
reset();
#if DEBUG_DUMP
fID = ++gContourID;
#endif
}
bool operator<(const Contour& rh) const {
return fBounds.fTop == rh.fBounds.fTop
? fBounds.fLeft < rh.fBounds.fLeft
: fBounds.fTop < rh.fBounds.fTop;
}
void addCoincident(int index, Contour* other, int otherIndex,
const Intersections& ts, bool swap) {
Coincidence& coincidence = *fCoincidences.append();
coincidence.fContours[0] = this;
coincidence.fContours[1] = other;
coincidence.fSegments[0] = index;
coincidence.fSegments[1] = otherIndex;
coincidence.fTs[swap][0] = ts.fT[0][0];
coincidence.fTs[swap][1] = ts.fT[0][1];
coincidence.fTs[!swap][0] = ts.fT[1][0];
coincidence.fTs[!swap][1] = ts.fT[1][1];
}
void addCross(const Contour* crosser) {
#ifdef DEBUG_CROSS
for (int index = 0; index < fCrosses.count(); ++index) {
SkASSERT(fCrosses[index] != crosser);
}
#endif
*fCrosses.append() = crosser;
}
void addCubic(const SkPoint pts[4]) {
fSegments.push_back().addCubic(pts);
fContainsCurves = true;
}
int addLine(const SkPoint pts[2]) {
fSegments.push_back().addLine(pts);
return fSegments.count();
}
void addOtherT(int segIndex, int tIndex, double otherT, int otherIndex) {
fSegments[segIndex].addOtherT(tIndex, otherT, otherIndex);
}
int addQuad(const SkPoint pts[3]) {
fSegments.push_back().addQuad(pts);
fContainsCurves = true;
return fSegments.count();
}
int addT(int segIndex, double newT, Contour* other, int otherIndex) {
containsIntercepts();
return fSegments[segIndex].addT(newT, &other->fSegments[otherIndex]);
}
const Bounds& bounds() const {
return fBounds;
}
void complete() {
setBounds();
fContainsIntercepts = false;
}
void containsIntercepts() {
fContainsIntercepts = true;
}
const Segment* crossedSegment(const SkPoint& basePt, SkScalar& bestY,
int &tIndex, double& hitT) {
int segmentCount = fSegments.count();
const Segment* bestSegment = NULL;
for (int test = 0; test < segmentCount; ++test) {
Segment* testSegment = &fSegments[test];
const SkRect& bounds = testSegment->bounds();
if (bounds.fBottom <= bestY) {
continue;
}
if (bounds.fTop >= basePt.fY) {
continue;
}
if (bounds.fLeft > basePt.fX) {
continue;
}
if (bounds.fRight < basePt.fX) {
continue;
}
if (bounds.fLeft == bounds.fRight) {
continue;
}
#if 0
bool leftHalf = bounds.fLeft == basePt.fX;
bool rightHalf = bounds.fRight == basePt.fX;
if ((leftHalf || rightHalf) && !testSegment->crossedSpanHalves(
basePt, leftHalf, rightHalf)) {
continue;
}
#endif
double testHitT;
int testT = testSegment->crossedSpan(basePt, bestY, testHitT);
if (testT >= 0) {
bestSegment = testSegment;
tIndex = testT;
hitT = testHitT;
}
}
return bestSegment;
}
bool crosses(const Contour* crosser) const {
for (int index = 0; index < fCrosses.count(); ++index) {
if (fCrosses[index] == crosser) {
return true;
}
}
return false;
}
void findTooCloseToCall(int xorMask) {
int segmentCount = fSegments.count();
for (int sIndex = 0; sIndex < segmentCount; ++sIndex) {
fSegments[sIndex].findTooCloseToCall(xorMask);
}
}
void fixOtherTIndex() {
int segmentCount = fSegments.count();
for (int sIndex = 0; sIndex < segmentCount; ++sIndex) {
fSegments[sIndex].fixOtherTIndex();
}
}
void reset() {
fSegments.reset();
fBounds.set(SK_ScalarMax, SK_ScalarMax, SK_ScalarMax, SK_ScalarMax);
fContainsCurves = fContainsIntercepts = false;
}
void resolveCoincidence(int xorMask) {
int count = fCoincidences.count();
for (int index = 0; index < count; ++index) {
Coincidence& coincidence = fCoincidences[index];
Contour* thisContour = coincidence.fContours[0];
Contour* otherContour = coincidence.fContours[1];
int thisIndex = coincidence.fSegments[0];
int otherIndex = coincidence.fSegments[1];
Segment& thisOne = thisContour->fSegments[thisIndex];
Segment& other = otherContour->fSegments[otherIndex];
#if DEBUG_CONCIDENT
thisOne.debugShowTs();
other.debugShowTs();
#endif
double startT = coincidence.fTs[0][0];
double endT = coincidence.fTs[0][1];
if (startT > endT) {
SkTSwap<double>(startT, endT);
}
SkASSERT(!approximately_negative(endT - startT));
double oStartT = coincidence.fTs[1][0];
double oEndT = coincidence.fTs[1][1];
if (oStartT > oEndT) {
SkTSwap<double>(oStartT, oEndT);
}
SkASSERT(!approximately_negative(oEndT - oStartT));
if (thisOne.cancels(other)) {
// make sure startT and endT have t entries
if (startT > 0 || oEndT < 1
|| thisOne.isMissing(startT) || other.isMissing(oEndT)) {
thisOne.addTPair(startT, other, oEndT, true);
}
if (oStartT > 0 || endT < 1
|| thisOne.isMissing(endT) || other.isMissing(oStartT)) {
other.addTPair(oStartT, thisOne, endT, true);
}
thisOne.addTCancel(startT, endT, other, oStartT, oEndT);
} else {
if (startT > 0 || oStartT > 0
|| thisOne.isMissing(startT) || other.isMissing(oStartT)) {
thisOne.addTPair(startT, other, oStartT, true);
}
if (endT < 1 || oEndT < 1
|| thisOne.isMissing(endT) || other.isMissing(oEndT)) {
other.addTPair(oEndT, thisOne, endT, true);
}
thisOne.addTCoincident(xorMask, startT, endT, other, oStartT, oEndT);
}
#if DEBUG_CONCIDENT
thisOne.debugShowTs();
other.debugShowTs();
#endif
}
}
const SkTArray<Segment>& segments() {
return fSegments;
}
// OPTIMIZATION: feel pretty uneasy about this. It seems like once again
// we need to sort and walk edges in y, but that on the surface opens the
// same can of worms as before. But then, this is a rough sort based on
// segments' top, and not a true sort, so it could be ameniable to regular
// sorting instead of linear searching. Still feel like I'm missing something
Segment* topSegment(SkScalar& bestY) {
int segmentCount = fSegments.count();
SkASSERT(segmentCount > 0);
int best = -1;
Segment* bestSegment = NULL;
while (++best < segmentCount) {
Segment* testSegment = &fSegments[best];
if (testSegment->done()) {
continue;
}
bestSegment = testSegment;
break;
}
if (!bestSegment) {
return NULL;
}
SkScalar bestTop = bestSegment->activeTop();
for (int test = best + 1; test < segmentCount; ++test) {
Segment* testSegment = &fSegments[test];
if (testSegment->done()) {
continue;
}
if (testSegment->bounds().fTop > bestTop) {
continue;
}
SkScalar testTop = testSegment->activeTop();
if (bestTop > testTop) {
bestTop = testTop;
bestSegment = testSegment;
}
}
bestY = bestTop;
return bestSegment;
}
Segment* undoneSegment(int& start, int& end) {
int segmentCount = fSegments.count();
for (int test = 0; test < segmentCount; ++test) {
Segment* testSegment = &fSegments[test];
if (testSegment->done()) {
continue;
}
testSegment->undoneSpan(start, end);
return testSegment;
}
return NULL;
}
int updateSegment(int index, const SkPoint* pts) {
Segment& segment = fSegments[index];
segment.updatePts(pts);
return segment.verb() + 1;
}
#if DEBUG_TEST
SkTArray<Segment>& debugSegments() {
return fSegments;
}
#endif
#if DEBUG_DUMP
void dump() {
int i;
const char className[] = "Contour";
const int tab = 4;
SkDebugf("%s %p (contour=%d)\n", className, this, fID);
for (i = 0; i < fSegments.count(); ++i) {
SkDebugf("%*s.fSegments[%d]:\n", tab + sizeof(className),
className, i);
fSegments[i].dump();
}
SkDebugf("%*s.fBounds=(l:%1.9g, t:%1.9g r:%1.9g, b:%1.9g)\n",
tab + sizeof(className), className,
fBounds.fLeft, fBounds.fTop,
fBounds.fRight, fBounds.fBottom);
SkDebugf("%*s.fContainsIntercepts=%d\n", tab + sizeof(className),
className, fContainsIntercepts);
SkDebugf("%*s.fContainsCurves=%d\n", tab + sizeof(className),
className, fContainsCurves);
}
#endif
#if DEBUG_ACTIVE_SPANS
void debugShowActiveSpans() {
for (int index = 0; index < fSegments.count(); ++index) {
fSegments[index].debugShowActiveSpans();
}
}
#endif
protected:
void setBounds() {
int count = fSegments.count();
if (count == 0) {
SkDebugf("%s empty contour\n", __FUNCTION__);
SkASSERT(0);
// FIXME: delete empty contour?
return;
}
fBounds = fSegments.front().bounds();
for (int index = 1; index < count; ++index) {
fBounds.add(fSegments[index].bounds());
}
}
private:
SkTArray<Segment> fSegments;
SkTDArray<Coincidence> fCoincidences;
SkTDArray<const Contour*> fCrosses;
Bounds fBounds;
bool fContainsIntercepts;
bool fContainsCurves;
#if DEBUG_DUMP
int fID;
#endif
};
class EdgeBuilder {
public:
EdgeBuilder(const SkPath& path, SkTArray<Contour>& contours)
: fPath(path)
, fCurrentContour(NULL)
, fContours(contours)
{
#if DEBUG_DUMP
gContourID = 0;
gSegmentID = 0;
#endif
walk();
}
protected:
void complete() {
if (fCurrentContour && fCurrentContour->segments().count()) {
fCurrentContour->complete();
fCurrentContour = NULL;
}
}
void walk() {
// FIXME:remove once we can access path pts directly
SkPath::RawIter iter(fPath); // FIXME: access path directly when allowed
SkPoint pts[4];
SkPath::Verb verb;
do {
verb = iter.next(pts);
*fPathVerbs.append() = verb;
if (verb == SkPath::kMove_Verb) {
*fPathPts.append() = pts[0];
} else if (verb >= SkPath::kLine_Verb && verb <= SkPath::kCubic_Verb) {
fPathPts.append(verb, &pts[1]);
}
} while (verb != SkPath::kDone_Verb);
// FIXME: end of section to remove once path pts are accessed directly
SkPath::Verb reducedVerb;
uint8_t* verbPtr = fPathVerbs.begin();
const SkPoint* pointsPtr = fPathPts.begin();
const SkPoint* finalCurveStart = NULL;
const SkPoint* finalCurveEnd = NULL;
while ((verb = (SkPath::Verb) *verbPtr++) != SkPath::kDone_Verb) {
switch (verb) {
case SkPath::kMove_Verb:
complete();
if (!fCurrentContour) {
fCurrentContour = fContours.push_back_n(1);
*fExtra.append() = -1; // start new contour
}
finalCurveEnd = pointsPtr++;
continue;
case SkPath::kLine_Verb:
// skip degenerate points
if (pointsPtr[-1].fX != pointsPtr[0].fX
|| pointsPtr[-1].fY != pointsPtr[0].fY) {
fCurrentContour->addLine(&pointsPtr[-1]);
}
break;
case SkPath::kQuad_Verb:
reducedVerb = QuadReduceOrder(&pointsPtr[-1], fReducePts);
if (reducedVerb == 0) {
break; // skip degenerate points
}
if (reducedVerb == 1) {
*fExtra.append() =
fCurrentContour->addLine(fReducePts.end() - 2);
break;
}
fCurrentContour->addQuad(&pointsPtr[-1]);
break;
case SkPath::kCubic_Verb:
reducedVerb = CubicReduceOrder(&pointsPtr[-1], fReducePts);
if (reducedVerb == 0) {
break; // skip degenerate points
}
if (reducedVerb == 1) {
*fExtra.append() =
fCurrentContour->addLine(fReducePts.end() - 2);
break;
}
if (reducedVerb == 2) {
*fExtra.append() =
fCurrentContour->addQuad(fReducePts.end() - 3);
break;
}
fCurrentContour->addCubic(&pointsPtr[-1]);
break;
case SkPath::kClose_Verb:
SkASSERT(fCurrentContour);
if (finalCurveStart && finalCurveEnd
&& *finalCurveStart != *finalCurveEnd) {
*fReducePts.append() = *finalCurveStart;
*fReducePts.append() = *finalCurveEnd;
*fExtra.append() =
fCurrentContour->addLine(fReducePts.end() - 2);
}
complete();
continue;
default:
SkDEBUGFAIL("bad verb");
return;
}
finalCurveStart = &pointsPtr[verb - 1];
pointsPtr += verb;
SkASSERT(fCurrentContour);
}
complete();
if (fCurrentContour && !fCurrentContour->segments().count()) {
fContours.pop_back();
}
// correct pointers in contours since fReducePts may have moved as it grew
int cIndex = 0;
int extraCount = fExtra.count();
SkASSERT(extraCount == 0 || fExtra[0] == -1);
int eIndex = 0;
int rIndex = 0;
while (++eIndex < extraCount) {
int offset = fExtra[eIndex];
if (offset < 0) {
++cIndex;
continue;
}
fCurrentContour = &fContours[cIndex];
rIndex += fCurrentContour->updateSegment(offset - 1,
&fReducePts[rIndex]);
}
fExtra.reset(); // we're done with this
}
private:
const SkPath& fPath;
SkTDArray<SkPoint> fPathPts; // FIXME: point directly to path pts instead
SkTDArray<uint8_t> fPathVerbs; // FIXME: remove
Contour* fCurrentContour;
SkTArray<Contour>& fContours;
SkTDArray<SkPoint> fReducePts; // segments created on the fly
SkTDArray<int> fExtra; // -1 marks new contour, > 0 offsets into contour
};
class Work {
public:
enum SegmentType {
kHorizontalLine_Segment = -1,
kVerticalLine_Segment = 0,
kLine_Segment = SkPath::kLine_Verb,
kQuad_Segment = SkPath::kQuad_Verb,
kCubic_Segment = SkPath::kCubic_Verb,
};
void addCoincident(Work& other, const Intersections& ts, bool swap) {
fContour->addCoincident(fIndex, other.fContour, other.fIndex, ts, swap);
}
// FIXME: does it make sense to write otherIndex now if we're going to
// fix it up later?
void addOtherT(int index, double otherT, int otherIndex) {
fContour->addOtherT(fIndex, index, otherT, otherIndex);
}
// Avoid collapsing t values that are close to the same since
// we walk ts to describe consecutive intersections. Since a pair of ts can
// be nearly equal, any problems caused by this should be taken care
// of later.
// On the edge or out of range values are negative; add 2 to get end
int addT(double newT, const Work& other) {
return fContour->addT(fIndex, newT, other.fContour, other.fIndex);
}
bool advance() {
return ++fIndex < fLast;
}
SkScalar bottom() const {
return bounds().fBottom;
}
const Bounds& bounds() const {
return fContour->segments()[fIndex].bounds();
}
const SkPoint* cubic() const {
return fCubic;
}
void init(Contour* contour) {
fContour = contour;
fIndex = 0;
fLast = contour->segments().count();
}
bool isAdjacent(const Work& next) {
return fContour == next.fContour && fIndex + 1 == next.fIndex;
}
bool isFirstLast(const Work& next) {
return fContour == next.fContour && fIndex == 0
&& next.fIndex == fLast - 1;
}
SkScalar left() const {
return bounds().fLeft;
}
void promoteToCubic() {
fCubic[0] = pts()[0];
fCubic[2] = pts()[1];
fCubic[3] = pts()[2];
fCubic[1].fX = (fCubic[0].fX + fCubic[2].fX * 2) / 3;
fCubic[1].fY = (fCubic[0].fY + fCubic[2].fY * 2) / 3;
fCubic[2].fX = (fCubic[3].fX + fCubic[2].fX * 2) / 3;
fCubic[2].fY = (fCubic[3].fY + fCubic[2].fY * 2) / 3;
}
const SkPoint* pts() const {
return fContour->segments()[fIndex].pts();
}
SkScalar right() const {
return bounds().fRight;
}
ptrdiff_t segmentIndex() const {
return fIndex;
}
SegmentType segmentType() const {
const Segment& segment = fContour->segments()[fIndex];
SegmentType type = (SegmentType) segment.verb();
if (type != kLine_Segment) {
return type;
}
if (segment.isHorizontal()) {
return kHorizontalLine_Segment;
}
if (segment.isVertical()) {
return kVerticalLine_Segment;
}
return kLine_Segment;
}
bool startAfter(const Work& after) {
fIndex = after.fIndex;
return advance();
}
SkScalar top() const {
return bounds().fTop;
}
SkPath::Verb verb() const {
return fContour->segments()[fIndex].verb();
}
SkScalar x() const {
return bounds().fLeft;
}
bool xFlipped() const {
return x() != pts()[0].fX;
}
SkScalar y() const {
return bounds().fTop;
}
bool yFlipped() const {
return y() != pts()[0].fY;
}
protected:
Contour* fContour;
SkPoint fCubic[4];
int fIndex;
int fLast;
};
#if DEBUG_ADD_INTERSECTING_TS
static void debugShowLineIntersection(int pts, const Work& wt,
const Work& wn, const double wtTs[2], const double wnTs[2]) {
if (!pts) {
SkDebugf("%s no intersect (%1.9g,%1.9g %1.9g,%1.9g) (%1.9g,%1.9g %1.9g,%1.9g)\n",
__FUNCTION__, wt.pts()[0].fX, wt.pts()[0].fY,
wt.pts()[1].fX, wt.pts()[1].fY, wn.pts()[0].fX, wn.pts()[0].fY,
wn.pts()[1].fX, wn.pts()[1].fY);
return;
}
SkPoint wtOutPt, wnOutPt;
LineXYAtT(wt.pts(), wtTs[0], &wtOutPt);
LineXYAtT(wn.pts(), wnTs[0], &wnOutPt);
SkDebugf("%s wtTs[0]=%g (%g,%g, %g,%g) (%g,%g)",
__FUNCTION__,
wtTs[0], wt.pts()[0].fX, wt.pts()[0].fY,
wt.pts()[1].fX, wt.pts()[1].fY, wtOutPt.fX, wtOutPt.fY);
if (pts == 2) {
SkDebugf(" wtTs[1]=%g", wtTs[1]);
}
SkDebugf(" wnTs[0]=%g (%g,%g, %g,%g) (%g,%g)",
wnTs[0], wn.pts()[0].fX, wn.pts()[0].fY,
wn.pts()[1].fX, wn.pts()[1].fY, wnOutPt.fX, wnOutPt.fY);
if (pts == 2) {
SkDebugf(" wnTs[1]=%g", wnTs[1]);
}
SkDebugf("\n");
}
#else
static void debugShowLineIntersection(int , const Work& ,
const Work& , const double [2], const double [2]) {
}
#endif
static bool addIntersectTs(Contour* test, Contour* next) {
if (test != next) {
if (test->bounds().fBottom < next->bounds().fTop) {
return false;
}
if (!Bounds::Intersects(test->bounds(), next->bounds())) {
return true;
}
}
Work wt;
wt.init(test);
bool foundCommonContour = test == next;
do {
Work wn;
wn.init(next);
if (test == next && !wn.startAfter(wt)) {
continue;
}
do {
if (!Bounds::Intersects(wt.bounds(), wn.bounds())) {
continue;
}
int pts;
Intersections ts;
bool swap = false;
switch (wt.segmentType()) {
case Work::kHorizontalLine_Segment:
swap = true;
switch (wn.segmentType()) {
case Work::kHorizontalLine_Segment:
case Work::kVerticalLine_Segment:
case Work::kLine_Segment: {
pts = HLineIntersect(wn.pts(), wt.left(),
wt.right(), wt.y(), wt.xFlipped(), ts);
debugShowLineIntersection(pts, wt, wn,
ts.fT[1], ts.fT[0]);
break;
}
case Work::kQuad_Segment: {
pts = HQuadIntersect(wn.pts(), wt.left(),
wt.right(), wt.y(), wt.xFlipped(), ts);
break;
}
case Work::kCubic_Segment: {
pts = HCubicIntersect(wn.pts(), wt.left(),
wt.right(), wt.y(), wt.xFlipped(), ts);
break;
}
default:
SkASSERT(0);
}
break;
case Work::kVerticalLine_Segment:
swap = true;
switch (wn.segmentType()) {
case Work::kHorizontalLine_Segment:
case Work::kVerticalLine_Segment:
case Work::kLine_Segment: {
pts = VLineIntersect(wn.pts(), wt.top(),
wt.bottom(), wt.x(), wt.yFlipped(), ts);
debugShowLineIntersection(pts, wt, wn,
ts.fT[1], ts.fT[0]);
break;
}
case Work::kQuad_Segment: {
pts = VQuadIntersect(wn.pts(), wt.top(),
wt.bottom(), wt.x(), wt.yFlipped(), ts);
break;
}
case Work::kCubic_Segment: {
pts = VCubicIntersect(wn.pts(), wt.top(),
wt.bottom(), wt.x(), wt.yFlipped(), ts);
break;
}
default:
SkASSERT(0);
}
break;
case Work::kLine_Segment:
switch (wn.segmentType()) {
case Work::kHorizontalLine_Segment:
pts = HLineIntersect(wt.pts(), wn.left(),
wn.right(), wn.y(), wn.xFlipped(), ts);
debugShowLineIntersection(pts, wt, wn,
ts.fT[1], ts.fT[0]);
break;
case Work::kVerticalLine_Segment:
pts = VLineIntersect(wt.pts(), wn.top(),
wn.bottom(), wn.x(), wn.yFlipped(), ts);
debugShowLineIntersection(pts, wt, wn,
ts.fT[1], ts.fT[0]);
break;
case Work::kLine_Segment: {
pts = LineIntersect(wt.pts(), wn.pts(), ts);
debugShowLineIntersection(pts, wt, wn,
ts.fT[1], ts.fT[0]);
break;
}
case Work::kQuad_Segment: {
swap = true;
pts = QuadLineIntersect(wn.pts(), wt.pts(), ts);
break;
}
case Work::kCubic_Segment: {
swap = true;
pts = CubicLineIntersect(wn.pts(), wt.pts(), ts);
break;
}
default:
SkASSERT(0);
}
break;
case Work::kQuad_Segment:
switch (wn.segmentType()) {
case Work::kHorizontalLine_Segment:
pts = HQuadIntersect(wt.pts(), wn.left(),
wn.right(), wn.y(), wn.xFlipped(), ts);
break;
case Work::kVerticalLine_Segment:
pts = VQuadIntersect(wt.pts(), wn.top(),
wn.bottom(), wn.x(), wn.yFlipped(), ts);
break;
case Work::kLine_Segment: {
pts = QuadLineIntersect(wt.pts(), wn.pts(), ts);
break;
}
case Work::kQuad_Segment: {
pts = QuadIntersect(wt.pts(), wn.pts(), ts);
break;
}
case Work::kCubic_Segment: {
wt.promoteToCubic();
pts = CubicIntersect(wt.cubic(), wn.pts(), ts);
break;
}
default:
SkASSERT(0);
}
break;
case Work::kCubic_Segment:
switch (wn.segmentType()) {
case Work::kHorizontalLine_Segment:
pts = HCubicIntersect(wt.pts(), wn.left(),
wn.right(), wn.y(), wn.xFlipped(), ts);
break;
case Work::kVerticalLine_Segment:
pts = VCubicIntersect(wt.pts(), wn.top(),
wn.bottom(), wn.x(), wn.yFlipped(), ts);
break;
case Work::kLine_Segment: {
pts = CubicLineIntersect(wt.pts(), wn.pts(), ts);
break;
}
case Work::kQuad_Segment: {
wn.promoteToCubic();
pts = CubicIntersect(wt.pts(), wn.cubic(), ts);
break;
}
case Work::kCubic_Segment: {
pts = CubicIntersect(wt.pts(), wn.pts(), ts);
break;
}
default:
SkASSERT(0);
}
break;
default:
SkASSERT(0);
}
if (!foundCommonContour && pts > 0) {
test->addCross(next);
next->addCross(test);
foundCommonContour = true;
}
// in addition to recording T values, record matching segment
if (pts == 2 && wn.segmentType() <= Work::kLine_Segment
&& wt.segmentType() <= Work::kLine_Segment) {
wt.addCoincident(wn, ts, swap);
continue;
}
for (int pt = 0; pt < pts; ++pt) {
SkASSERT(ts.fT[0][pt] >= 0 && ts.fT[0][pt] <= 1);
SkASSERT(ts.fT[1][pt] >= 0 && ts.fT[1][pt] <= 1);
int testTAt = wt.addT(ts.fT[swap][pt], wn);
int nextTAt = wn.addT(ts.fT[!swap][pt], wt);
wt.addOtherT(testTAt, ts.fT[!swap][pt], nextTAt);
wn.addOtherT(nextTAt, ts.fT[swap][pt], testTAt);
}
} while (wn.advance());
} while (wt.advance());
return true;
}
// resolve any coincident pairs found while intersecting, and
// see if coincidence is formed by clipping non-concident segments
static void coincidenceCheck(SkTDArray<Contour*>& contourList, int xorMask) {
int contourCount = contourList.count();
for (int cIndex = 0; cIndex < contourCount; ++cIndex) {
Contour* contour = contourList[cIndex];
contour->resolveCoincidence(xorMask);
}
for (int cIndex = 0; cIndex < contourCount; ++cIndex) {
Contour* contour = contourList[cIndex];
contour->findTooCloseToCall(xorMask);
}
}
// project a ray from the top of the contour up and see if it hits anything
// note: when we compute line intersections, we keep track of whether
// two contours touch, so we need only look at contours not touching this one.
// OPTIMIZATION: sort contourList vertically to avoid linear walk
static int innerContourCheck(SkTDArray<Contour*>& contourList,
const Segment* current, int index, int endIndex) {
const SkPoint& basePt = current->xyAtT(endIndex);
int contourCount = contourList.count();
SkScalar bestY = SK_ScalarMin;
const Segment* test = NULL;
int tIndex;
double tHit;
// bool checkCrosses = true;
for (int cTest = 0; cTest < contourCount; ++cTest) {
Contour* contour = contourList[cTest];
if (basePt.fY < contour->bounds().fTop) {
continue;
}
if (bestY > contour->bounds().fBottom) {
continue;
}
#if 0
// even though the contours crossed, if spans cancel through concidence,
// the contours may be not have any span links to chase, and the current
// segment may be isolated. Detect this by seeing if current has
// uninitialized wind sums. If so, project a ray instead of relying on
// previously found intersections.
if (baseContour == contour) {
continue;
}
if (checkCrosses && baseContour->crosses(contour)) {
if (current->isConnected(index, endIndex)) {
continue;
}
checkCrosses = false;
}
#endif
const Segment* next = contour->crossedSegment(basePt, bestY, tIndex, tHit);
if (next) {
test = next;
}
}
if (!test) {
return 0;
}
int winding, windValue;
// If the ray hit the end of a span, we need to construct the wheel of
// angles to find the span closest to the ray -- even if there are just
// two spokes on the wheel.
const Angle* angle = NULL;
if (approximately_zero(tHit - test->t(tIndex))) {
SkTDArray<Angle> angles;
int end = test->nextSpan(tIndex, 1);
if (end < 0) {
end = test->nextSpan(tIndex, -1);
}
test->addTwoAngles(end, tIndex, angles);
SkASSERT(angles.count() > 0);
if (angles[0].segment()->yAtT(angles[0].start()) >= basePt.fY) {
#if DEBUG_SORT
SkDebugf("%s early return\n", __FUNCTION__);
#endif
return 0;
}
test->buildAngles(tIndex, angles);
SkTDArray<Angle*> sorted;
// OPTIMIZATION: call a sort that, if base point is the leftmost,
// returns the first counterclockwise hour before 6 o'clock,
// or if the base point is rightmost, returns the first clockwise
// hour after 6 o'clock
sortAngles(angles, sorted);
#if DEBUG_SORT
sorted[0]->segment()->debugShowSort(__FUNCTION__, sorted, 0, 0);
#endif
// walk the sorted angle fan to find the lowest angle
// above the base point. Currently, the first angle in the sorted array
// is 12 noon or an earlier hour (the next counterclockwise)
int count = sorted.count();
int left = -1;
int mid = -1;
int right = -1;
bool baseMatches = test->yAtT(tIndex) == basePt.fY;
for (int index = 0; index < count; ++index) {
angle = sorted[index];
if (baseMatches && angle->isHorizontal()) {
continue;
}
double indexDx = angle->dx();
if (indexDx < 0) {
left = index;
} else if (indexDx > 0) {
right = index;
int previous = index - 1;
if (previous < 0) {
previous = count - 1;
}
const Angle* prev = sorted[previous];
if (prev->dy() >= 0 && prev->dx() > 0 && angle->dy() < 0) {
#if DEBUG_SORT
SkDebugf("%s use prev\n", __FUNCTION__);
#endif
right = previous;
}
break;
} else {
mid = index;
}
}
if (left < 0 && right < 0) {
left = mid;
}
SkASSERT(left >= 0 || right >= 0);
if (left < 0) {
left = right;
} else if (left >= 0 && mid >= 0 && right >= 0
&& sorted[mid]->sign() == sorted[right]->sign()) {
left = right;
}
angle = sorted[left];
test = angle->segment();
winding = test->windSum(angle);
SkASSERT(winding != SK_MinS32);
windValue = test->windValue(angle);
#if DEBUG_WINDING
SkDebugf("%s angle winding=%d windValue=%d sign=%d\n", __FUNCTION__, winding,
windValue, angle->sign());
#endif
} else {
winding = test->windSum(tIndex);
SkASSERT(winding != SK_MinS32);
windValue = test->windValue(tIndex);
#if DEBUG_WINDING
SkDebugf("%s single winding=%d windValue=%d\n", __FUNCTION__, winding,
windValue);
#endif
}
// see if a + change in T results in a +/- change in X (compute x'(T))
SkScalar dx = (*SegmentDXAtT[test->verb()])(test->pts(), tHit);
#if DEBUG_WINDING
SkDebugf("%s dx=%1.9g\n", __FUNCTION__, dx);
#endif
SkASSERT(dx != 0);
if (winding * dx > 0) { // if same signs, result is negative
winding += dx > 0 ? -windValue : windValue;
#if DEBUG_WINDING
SkDebugf("%s final winding=%d\n", __FUNCTION__, winding);
#endif
}
// start here;
// we're broken because we find a vertical span
return winding;
}
// OPTIMIZATION: not crazy about linear search here to find top active y.
// seems like we should break down and do the sort, or maybe sort each
// contours' segments?
// Once the segment array is built, there's no reason I can think of not to
// sort it in Y. hmmm
// FIXME: return the contour found to pass to inner contour check
static Segment* findTopContour(SkTDArray<Contour*>& contourList) {
int contourCount = contourList.count();
int cIndex = 0;
Segment* topStart;
SkScalar bestY = SK_ScalarMax;
Contour* contour;
do {
contour = contourList[cIndex];
topStart = contour->topSegment(bestY);
} while (!topStart && ++cIndex < contourCount);
if (!topStart) {
return NULL;
}
while (++cIndex < contourCount) {
contour = contourList[cIndex];
if (bestY < contour->bounds().fTop) {
continue;
}
SkScalar testY = SK_ScalarMax;
Segment* test = contour->topSegment(testY);
if (!test || bestY <= testY) {
continue;
}
topStart = test;
bestY = testY;
}
return topStart;
}
static Segment* findUndone(SkTDArray<Contour*>& contourList, int& start, int& end) {
int contourCount = contourList.count();
Segment* result;
for (int cIndex = 0; cIndex < contourCount; ++cIndex) {
Contour* contour = contourList[cIndex];
result = contour->undoneSegment(start, end);
if (result) {
return result;
}
}
return NULL;
}
static Segment* findChase(SkTDArray<Span*>& chase, int& tIndex, int& endIndex,
int contourWinding) {
while (chase.count()) {
Span* span = chase[chase.count() - 1];
const Span& backPtr = span->fOther->span(span->fOtherIndex);
Segment* segment = backPtr.fOther;
tIndex = backPtr.fOtherIndex;
SkTDArray<Angle> angles;
int done = 0;
if (segment->activeAngle(tIndex, done, angles)) {
Angle* last = angles.end() - 1;
tIndex = last->start();
endIndex = last->end();
return last->segment();
}
if (done == angles.count()) {
chase.pop(&span);
continue;
}
SkTDArray<Angle*> sorted;
sortAngles(angles, sorted);
#if DEBUG_SORT
sorted[0]->segment()->debugShowSort(__FUNCTION__, sorted, 0, 0);
#endif
// find first angle, initialize winding to computed fWindSum
int firstIndex = -1;
const Angle* angle;
int winding;
do {
angle = sorted[++firstIndex];
segment = angle->segment();
winding = segment->windSum(angle);
} while (winding == SK_MinS32);
int spanWinding = segment->spanSign(angle->start(), angle->end());
#if DEBUG_WINDING
SkDebugf("%s winding=%d spanWinding=%d contourWinding=%d\n",
__FUNCTION__, winding, spanWinding, contourWinding);
#endif
// turn swinding into contourWinding
if (spanWinding * winding < 0) {
winding += spanWinding;
}
#if DEBUG_SORT
segment->debugShowSort(__FUNCTION__, sorted, firstIndex, winding);
#endif
// we care about first sign and whether wind sum indicates this
// edge is inside or outside. Maybe need to pass span winding
// or first winding or something into this function?
// advance to first undone angle, then return it and winding
// (to set whether edges are active or not)
int nextIndex = firstIndex + 1;
int angleCount = sorted.count();
int lastIndex = firstIndex != 0 ? firstIndex : angleCount;
angle = sorted[firstIndex];
winding -= angle->segment()->spanSign(angle);
do {
SkASSERT(nextIndex != firstIndex);
if (nextIndex == angleCount) {
nextIndex = 0;
}
angle = sorted[nextIndex];
segment = angle->segment();
int maxWinding = winding;
winding -= segment->spanSign(angle);
#if DEBUG_SORT
SkDebugf("%s id=%d maxWinding=%d winding=%d sign=%d\n", __FUNCTION__,
segment->debugID(), maxWinding, winding, angle->sign());
#endif
tIndex = angle->start();
endIndex = angle->end();
int lesser = SkMin32(tIndex, endIndex);
const Span& nextSpan = segment->span(lesser);
if (!nextSpan.fDone) {
#if 1
// FIXME: this be wrong. assign startWinding if edge is in
// same direction. If the direction is opposite, winding to
// assign is flipped sign or +/- 1?
if (useInnerWinding(maxWinding, winding)) {
maxWinding = winding;
}
segment->markWinding(lesser, maxWinding);
#endif
break;
}
} while (++nextIndex != lastIndex);
return segment;
}
return NULL;
}
#if DEBUG_ACTIVE_SPANS
static void debugShowActiveSpans(SkTDArray<Contour*>& contourList) {
for (int index = 0; index < contourList.count(); ++ index) {
contourList[index]->debugShowActiveSpans();
}
}
#endif
static bool windingIsActive(int winding, int spanWinding) {
return winding * spanWinding <= 0 && abs(winding) <= abs(spanWinding)
&& (!winding || !spanWinding || winding == -spanWinding);
}
// Each segment may have an inside or an outside. Segments contained within
// winding may have insides on either side, and form a contour that should be
// ignored. Segments that are coincident with opposing direction segments may
// have outsides on either side, and should also disappear.
// 'Normal' segments will have one inside and one outside. Subsequent connections
// when winding should follow the intersection direction. If more than one edge
// is an option, choose first edge that continues the inside.
// since we start with leftmost top edge, we'll traverse through a
// smaller angle counterclockwise to get to the next edge.
static void bridgeWinding(SkTDArray<Contour*>& contourList, SkPath& simple) {
bool firstContour = true;
do {
Segment* topStart = findTopContour(contourList);
if (!topStart) {
break;
}
// Start at the top. Above the top is outside, below is inside.
// follow edges to intersection by changing the index by direction.
int index, endIndex;
Segment* current = topStart->findTop(index, endIndex);
int contourWinding;
if (firstContour) {
contourWinding = 0;
firstContour = false;
} else {
int sumWinding = current->windSum(SkMin32(index, endIndex));
// FIXME: don't I have to adjust windSum to get contourWinding?
if (sumWinding == SK_MinS32) {
sumWinding = current->computeSum(index, endIndex);
}
if (sumWinding == SK_MinS32) {
contourWinding = innerContourCheck(contourList, current,
index, endIndex);
} else {
contourWinding = sumWinding;
int spanWinding = current->spanSign(index, endIndex);
bool inner = useInnerWinding(sumWinding - spanWinding, sumWinding);
if (inner) {
contourWinding -= spanWinding;
}
#if DEBUG_WINDING
SkDebugf("%s sumWinding=%d spanWinding=%d sign=%d inner=%d result=%d\n", __FUNCTION__,
sumWinding, spanWinding, SkSign32(index - endIndex),
inner, contourWinding);
#endif
}
#if DEBUG_WINDING
// SkASSERT(current->debugVerifyWinding(index, endIndex, contourWinding));
SkDebugf("%s contourWinding=%d\n", __FUNCTION__, contourWinding);
#endif
}
SkPoint lastPt;
int winding = contourWinding;
int spanWinding = current->spanSign(index, endIndex);
// FIXME: needs work. While it works in limited situations, it does
// not always compute winding correctly. Active should be removed and instead
// the initial winding should be correctly passed in so that if the
// inner contour is wound the same way, it never finds an accumulated
// winding of zero. Inside 'find next', we need to look for transitions
// other than zero when resolving sorted angles.
bool active = windingIsActive(winding, spanWinding);
SkTDArray<Span*> chaseArray;
do {
#if DEBUG_WINDING
SkDebugf("%s active=%s winding=%d spanWinding=%d\n",
__FUNCTION__, active ? "true" : "false",
winding, spanWinding);
#endif
const SkPoint* firstPt = NULL;
do {
SkASSERT(!current->done());
int nextStart = index;
int nextEnd = endIndex;
Segment* next = current->findNextWinding(chaseArray, active,
nextStart, nextEnd, winding, spanWinding);
if (!next) {
if (active && firstPt && current->verb() != SkPath::kLine_Verb && *firstPt != lastPt) {
lastPt = current->addCurveTo(index, endIndex, simple, true);
SkASSERT(*firstPt == lastPt);
}
break;
}
if (!firstPt) {
firstPt = &current->addMoveTo(index, simple, active);
}
lastPt = current->addCurveTo(index, endIndex, simple, active);
current = next;
index = nextStart;
endIndex = nextEnd;
} while (*firstPt != lastPt && (active || !current->done()));
if (firstPt && active) {
#if DEBUG_PATH_CONSTRUCTION
SkDebugf("%s close\n", __FUNCTION__);
#endif
simple.close();
}
current = findChase(chaseArray, index, endIndex, contourWinding);
#if DEBUG_ACTIVE_SPANS
debugShowActiveSpans(contourList);
#endif
if (!current) {
break;
}
int lesser = SkMin32(index, endIndex);
spanWinding = current->spanSign(index, endIndex);
winding = current->windSum(lesser);
bool inner = useInnerWinding(winding - spanWinding, winding);
#if DEBUG_WINDING
SkDebugf("%s id=%d t=%1.9g spanWinding=%d winding=%d sign=%d"
" inner=%d result=%d\n",
__FUNCTION__, current->debugID(), current->t(lesser),
spanWinding, winding, SkSign32(index - endIndex),
useInnerWinding(winding - spanWinding, winding),
inner ? winding - spanWinding : winding);
#endif
if (inner) {
winding -= spanWinding;
}
active = windingIsActive(winding, spanWinding);
} while (true);
} while (true);
}
static void bridgeXor(SkTDArray<Contour*>& contourList, SkPath& simple) {
Segment* current;
int start, end;
while ((current = findUndone(contourList, start, end))) {
const SkPoint* firstPt = NULL;
SkPoint lastPt;
do {
SkASSERT(!current->done());
int nextStart = start;
int nextEnd = end;
Segment* next = current->findNextXor(nextStart, nextEnd);
if (!next) {
if (firstPt && current->verb() != SkPath::kLine_Verb && *firstPt != lastPt) {
lastPt = current->addCurveTo(start, end, simple, true);
SkASSERT(*firstPt == lastPt);
}
break;
}
if (!firstPt) {
firstPt = &current->addMoveTo(start, simple, true);
}
lastPt = current->addCurveTo(start, end, simple, true);
current = next;
start = nextStart;
end = nextEnd;
} while (*firstPt != lastPt);
if (firstPt) {
#if DEBUG_PATH_CONSTRUCTION
SkDebugf("%s close\n", __FUNCTION__);
#endif
simple.close();
}
}
}
static void fixOtherTIndex(SkTDArray<Contour*>& contourList) {
int contourCount = contourList.count();
for (int cTest = 0; cTest < contourCount; ++cTest) {
Contour* contour = contourList[cTest];
contour->fixOtherTIndex();
}
}
static void makeContourList(SkTArray<Contour>& contours,
SkTDArray<Contour*>& list) {
int count = contours.count();
if (count == 0) {
return;
}
for (int index = 0; index < count; ++index) {
*list.append() = &contours[index];
}
QSort<Contour>(list.begin(), list.end() - 1);
}
void simplifyx(const SkPath& path, SkPath& simple) {
// returns 1 for evenodd, -1 for winding, regardless of inverse-ness
int xorMask = (path.getFillType() & 1) ? 1 : -1;
simple.reset();
simple.setFillType(SkPath::kEvenOdd_FillType);
// turn path into list of segments
SkTArray<Contour> contours;
// FIXME: add self-intersecting cubics' T values to segment
EdgeBuilder builder(path, contours);
SkTDArray<Contour*> contourList;
makeContourList(contours, contourList);
Contour** currentPtr = contourList.begin();
if (!currentPtr) {
return;
}
Contour** listEnd = contourList.end();
// find all intersections between segments
do {
Contour** nextPtr = currentPtr;
Contour* current = *currentPtr++;
Contour* next;
do {
next = *nextPtr++;
} while (addIntersectTs(current, next) && nextPtr != listEnd);
} while (currentPtr != listEnd);
// eat through coincident edges
coincidenceCheck(contourList, xorMask);
fixOtherTIndex(contourList);
// construct closed contours
if (xorMask < 0) {
bridgeWinding(contourList, simple);
} else {
bridgeXor(contourList, simple);
}
}
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