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skia2/experimental/Intersection/SkAntiEdge.cpp
caryclark@google.com 1304bb25aa shape ops work in progress 
git-svn-id: http://skia.googlecode.com/svn/trunk@8137 2bbb7eff-a529-9590-31e7-b0007b416f81
2013-03-13 20:29:41 +00:00

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/*
* Copyright 2011 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "SkAntiEdge.h"
#include "SkPoint.h"
void SkAntiEdge::pointOnLine(SkFixed x, SkFixed y) {
float x0 = SkFixedToFloat(x);
float y0 = SkFixedToFloat(y);
float x1 = SkFixedToFloat(fFirstX);
float y1 = SkFixedToFloat(fFirstY);
float x2 = SkFixedToFloat(fLastX);
float y2 = SkFixedToFloat(fLastY);
float numer = (x2 - x1) * (y1 - y0) - (x1 - x0) * (y2 - y1);
float denom = (x2 - x1) * (x2 - x1) + (y2 - y1) * (y2 - y1);
double dist = fabs(numer) / sqrt(denom);
SkAssertResult(dist < 0.01);
}
void SkAntiEdge::pointInLine(SkFixed x, SkFixed y) {
if (y == SK_MaxS32) {
return;
}
pointOnLine(x, y);
SkAssertResult(y >= fFirstY && y <= fLastY);
}
void SkAntiEdge::validate() {
pointOnLine(fWalkX, fY);
pointOnLine(fX, fWalkY);
}
bool SkAntiEdge::setLine(const SkPoint& p0, const SkPoint& p1) {
fFirstY = SkScalarToFixed(p0.fY);
fLastY = SkScalarToFixed(p1.fY);
if (fFirstY == fLastY) {
return false;
}
fFirstX = SkScalarToFixed(p0.fX);
fLastX = SkScalarToFixed(p1.fX);
if (fFirstY > fLastY) {
SkTSwap(fFirstX, fLastX);
SkTSwap(fFirstY, fLastY);
fWinding = -1;
} else {
fWinding = 1;
}
SkFixed dx = fLastX - fFirstX;
fDXFlipped = dx < 0;
SkFixed dy = fLastY - fFirstY;
fDX = SkFixedDiv(dx, dy);
fDY = dx == 0 ? SK_MaxS32 : SkFixedDiv(dy, SkFixedAbs(dx));
fLink = NULL;
fLinkSet = false;
return true;
}
void SkAntiEdge::calcLine() {
SkFixed yStartFrac = SkFixedFraction(fFirstY);
if (fDXFlipped) {
SkFixed vert = SK_Fixed1 - yStartFrac; // distance from y start to x-axis
fX0 = fFirstX + SkFixedMul(fDX, vert);
SkFixed backupX = fFirstX + SkFixedMul(vert, fDX); // x cell to back up to
SkFixed cellX = SkIntToFixed(SkFixedFloor(backupX));
SkFixed endX = SkIntToFixed(SkFixedFloor(fLastX));
if (cellX < endX) {
cellX = endX;
}
SkFixed distX = fFirstX - cellX; // to y-axis
fY0 = fFirstY + SkFixedMul(fDY, distX);
SkFixed rowBottom = SkIntToFixed(SkFixedCeil(fFirstY + 1));
if (fLastY > rowBottom) {
fPartialY = 0;
fX = fX0;
fY = rowBottom;
} else {
fPartialY = SkFixedFraction(fLastY);
fX = fLastX;
fY = fLastY;
}
} else {
fPartialY = yStartFrac;
fX0 = fFirstX - SkFixedMul(fDX, yStartFrac);
fY0 = fFirstY;
if (fDY != SK_MaxS32) {
SkFixed xStartFrac = SkFixedFraction(fFirstX);
fY0 -= SkFixedMul(fDY, xStartFrac);
}
fX = fFirstX;
fY = fFirstY;
}
fWalkX = fX;
fWalkY = fY;
fFinished = false;
}
static SkFixed SkFixedAddPin(SkFixed a, SkFixed b) {
SkFixed result = a + b;
if (((a ^ ~b) & (a ^ result)) >= 0) { // one positive, one negative
return result; // or all three same sign
}
return a < 0 ? -SK_FixedMax : SK_FixedMax;
}
// edge is increasing in x and y
uint16_t SkAntiEdge::advanceX(SkFixed left) {
validate();
SkFixed x = SkFixedAddPin(fX0, fDX);
SkFixed wy = SkIntToFixed(SkFixedFloor(fWalkY + SK_Fixed1));
pointOnLine(x, wy);
SkFixed partial = SK_Fixed1 - fPartialY;
SkFixed bottomPartial = wy - fLastY;
if (bottomPartial > 0) {
partial -= bottomPartial;
}
if (x > fLastX) {
x = fLastX;
wy = fLastY;
}
uint16_t coverage;
if (left >= x) {
fFinished = true;
coverage = partial - 1; // walker is to the right of edge
} else {
SkFixed y = SkFixedAddPin(fY0, fDY);
SkFixed wx = SkIntToFixed(SkFixedFloor(fWalkX + SK_Fixed1));
if (fDY != SK_MaxS32) {
pointOnLine(wx, y);
}
if (y > fLastY) {
y = fLastY;
wx = fLastX;
}
bool topCorner = fWalkX <= fX;
bool bottomCorner = x <= wx;
bool halfPlane = !(topCorner ^ bottomCorner);
if (halfPlane) {
if (x - SkIntToFixed(SkFixedFloor(fX)) <= SK_Fixed1) {
coverage = ~((fX + x) >> 1); // avg of fx, fx+dx
fFinished = true;
if (x >= left + SK_Fixed1) {
fWalkX = wx;
fY = fY0 = y;
}
} else {
SkAssertResult(y - SkIntToFixed(SkFixedFloor(fY)) <= SK_Fixed1);
coverage = ((fY + y) >> 1);
fFinished = y == fLastY;
fWalkX = wx;
fY = fY0 = y;
}
coverage = coverage * partial >> 16;
} else if (topCorner) {
SkFixed xDiff = wx - fX;
SkAssertResult(xDiff >= 0);
SkAssertResult(xDiff <= SK_Fixed1);
SkFixed yDiff = y - fWalkY;
// This may be a very small negative number if error accumulates
// FIXME: for now, try setting it to zero in that case.
if (yDiff < 0) {
fX = fX0 = SkIntToFixed(SkFixedCeil(fX));
yDiff = 0;
}
SkAssertResult(yDiff >= 0);
SkAssertResult(yDiff <= SK_Fixed1);
int xCoverage = xDiff >> 1; // throw away 1 bit so multiply
int yCoverage = yDiff >> 1; // stays in range
int triangle = xCoverage * yCoverage; // 30 bits
SkFixed bottomPartial = y - fLastY;
fFinished = bottomPartial >= 0;
if (fFinished) {
yCoverage = bottomPartial >> 1;
xCoverage = (wx - fLastX) >> 1;
triangle -= xCoverage * yCoverage;
}
coverage = triangle >> 15;
fWalkX = wx;
fY = fY0 = y;
} else {
SkAssertResult(bottomCorner);
SkFixed xDiff = x - fWalkX;
SkAssertResult(xDiff >= 0);
SkAssertResult(xDiff <= SK_Fixed1);
SkFixed yDiff = wy - fY;
SkAssertResult(yDiff >= 0);
SkAssertResult(yDiff <= SK_Fixed1);
int xCoverage = xDiff >> 1; // throw away 1 bit so multiply
int yCoverage = yDiff >> 1; // stays in range
int triangle = xCoverage * yCoverage >> 15;
coverage = partial - 1 - triangle;
fFinished = true;
}
}
validate();
return coverage;
}
// edge is increasing in x, but decreasing in y
uint16_t SkAntiEdge::advanceFlippedX(SkFixed left) {
validate();
SkFixed x = SkFixedAddPin(fX0, -fDX);
SkFixed wy = SkIntToFixed(SkFixedFloor(fWalkY - 1));
pointOnLine(x, wy);
SkFixed partial = fPartialY ? fPartialY : SK_Fixed1;
SkFixed topPartial = fFirstY - wy;
if (topPartial > 0) {
partial -= topPartial;
}
if (x > fFirstX) {
x = fFirstX;
wy = fFirstY;
}
uint16_t coverage;
if (left >= x) {
fFinished = true;
coverage = partial - 1; // walker is to the right of edge
} else {
SkFixed y = SkFixedAddPin(fY0, -fDY);
SkFixed wx = SkIntToFixed(SkFixedFloor(fWalkX + SK_Fixed1));
pointOnLine(wx, y);
if (y < fFirstY) {
y = fFirstY;
wx = fFirstX;
}
bool bottomCorner = fWalkX <= fX;
bool topCorner = x <= wx;
bool halfPlane = !(topCorner ^ bottomCorner);
if (halfPlane) {
if (x - SkIntToFixed(SkFixedFloor(fX)) <= SK_Fixed1) {
coverage = ~((fX + x) >> 1); // avg of fx, fx+dx
fFinished = true;
} else {
SkAssertResult(y - SkIntToFixed(SkFixedFloor(fY)) <= SK_Fixed1);
coverage = ~((fY + y) >> 1);
fFinished = y == fY;
fWalkX = wx;
fY = fY0 = y;
}
coverage = coverage * partial >> 16;
} else if (bottomCorner) {
SkFixed xDiff = wx - fX;
SkAssertResult(xDiff >= 0);
SkAssertResult(xDiff <= SK_Fixed1);
SkFixed yDiff = fWalkY - y;
SkAssertResult(yDiff >= 0);
SkAssertResult(yDiff <= SK_Fixed1);
int xCoverage = xDiff >> 1; // throw away 1 bit so multiply
int yCoverage = yDiff >> 1; // stays in range
int triangle = xCoverage * yCoverage; // 30 bits
SkFixed bottomPartial = fFirstY - y;
fFinished = bottomPartial >= 0;
if (fFinished) {
yCoverage = bottomPartial >> 1;
xCoverage = (wx - fFirstX) >> 1;
triangle -= xCoverage * yCoverage;
}
coverage = triangle >> 15;
fWalkX = wx;
fY = fY0 = y;
} else {
SkAssertResult(topCorner);
SkFixed xDiff = x - fWalkX;
SkAssertResult(xDiff >= 0);
SkAssertResult(xDiff <= SK_Fixed1);
SkFixed yDiff = fY - wy;
SkAssertResult(yDiff >= 0);
SkAssertResult(yDiff <= SK_Fixed1);
int xCoverage = xDiff >> 1; // throw away 1 bit so multiply
int yCoverage = yDiff >> 1; // stays in range
int triangle = xCoverage * yCoverage >> 15;
coverage = partial - 1 - triangle;
fFinished = true;
}
}
validate();
return coverage;
}
void SkAntiEdge::advanceY(SkFixed top) {
validate();
fX0 = SkFixedAddPin(fX0, fDX);
fPartialY = 0;
if (fDXFlipped) {
if (fX0 < fLastX) {
fWalkX = fX = fLastX;
} else {
fWalkX = fX = fX0;
}
SkFixed bottom = top + SK_Fixed1;
if (bottom > fLastY) {
bottom = fLastY;
}
SkFixed vert = bottom - fFirstY; // distance from y start to x-axis
SkFixed backupX = fFirstX + SkFixedMul(vert, fDX); // x cell to back up to
SkFixed distX = fFirstX - SkIntToFixed(SkFixedFloor(backupX)); // to y-axis
fY0 = fFirstY + SkFixedMul(fDY, distX);
fY = top + SK_Fixed1;
if (fY > fLastY) {
fY = fLastY;
}
if (fLastY < top + SK_Fixed1) {
fPartialY = SkFixedFraction(fLastY);
}
} else {
if (fX0 > fLastX) {
fX0 = fLastX;
}
fX = fX0;
}
fWalkY = SkIntToFixed(SkFixedFloor(fWalkY + SK_Fixed1));
if (fWalkY > fLastY) {
fWalkY = fLastY;
}
validate();
fFinished = false;
}
int SkAntiEdgeBuilder::build(const SkPoint pts[], int count) {
SkAntiEdge* edge = fEdges.append();
for (int index = 0; index < count; ++index) {
if (edge->setLine(pts[index], pts[(index + 1) % count])) {
edge = fEdges.append();
}
}
int result = fEdges.count();
fEdges.setCount(--result);
if (result > 0) {
sk_bzero(&fHeadEdge, sizeof(fHeadEdge));
sk_bzero(&fTailEdge, sizeof(fTailEdge));
for (int index = 0; index < result; ++index) {
*fList.append() = &fEdges[index];
}
}
return result;
}
void SkAntiEdgeBuilder::calc() {
for (SkAntiEdge* active = fEdges.begin(); active != fEdges.end(); ++active) {
active->calcLine();
}
// compute winding sum for edges
SkAntiEdge* first = fHeadEdge.fNext;
SkAntiEdge* active;
SkAntiEdge* listTop = first;
for (active = first; active != &fTailEdge; active = active->fNext) {
active->fWindingSum = active->fWinding;
while (listTop->fLastY < active->fFirstY) {
listTop = listTop->fNext;
}
for (SkAntiEdge* check = listTop; check->fFirstY <= active->fFirstY; check = check->fNext) {
if (check == active) {
continue;
}
if (check->fLastY <= active->fFirstY) {
continue;
}
if (check->fFirstX > active->fFirstX) {
continue;
}
if (check->fFirstX == active->fFirstX && check->fDX > active->fDX) {
continue;
}
active->fWindingSum += check->fWinding;
}
}
}
extern "C" {
static int edge_compare(const void* a, const void* b) {
const SkAntiEdge* edgea = *(const SkAntiEdge**)a;
const SkAntiEdge* edgeb = *(const SkAntiEdge**)b;
int valuea = edgea->fFirstY;
int valueb = edgeb->fFirstY;
if (valuea == valueb) {
valuea = edgea->fFirstX;
valueb = edgeb->fFirstX;
}
if (valuea == valueb) {
valuea = edgea->fDX;
valueb = edgeb->fDX;
}
return valuea - valueb;
}
}
void SkAntiEdgeBuilder::sort(SkTDArray<SkAntiEdge*>& listOfEdges) {
SkAntiEdge** list = listOfEdges.begin();
int count = listOfEdges.count();
qsort(list, count, sizeof(SkAntiEdge*), edge_compare);
// link the edges in sorted order
for (int i = 1; i < count; i++) {
list[i - 1]->fNext = list[i];
list[i]->fPrev = list[i - 1];
}
}
#define kEDGE_HEAD_XY SK_MinS32
#define kEDGE_TAIL_XY SK_MaxS32
void SkAntiEdgeBuilder::sort() {
sort(fList);
SkAntiEdge* last = fList.end()[-1];
fHeadEdge.fNext = fList[0];
fHeadEdge.fFirstX = fHeadEdge.fFirstY = fHeadEdge.fWalkY = fHeadEdge.fLastY = kEDGE_HEAD_XY;
fList[0]->fPrev = &fHeadEdge;
fTailEdge.fPrev = last;
fTailEdge.fFirstX = fTailEdge.fFirstY = fTailEdge.fWalkY = fTailEdge.fLastY = kEDGE_TAIL_XY;
last->fNext = &fTailEdge;
}
static inline void remove_edge(SkAntiEdge* edge) {
edge->fPrev->fNext = edge->fNext;
edge->fNext->fPrev = edge->fPrev;
}
static inline void swap_edges(SkAntiEdge* prev, SkAntiEdge* next) {
SkASSERT(prev->fNext == next && next->fPrev == prev);
// remove prev from the list
prev->fPrev->fNext = next;
next->fPrev = prev->fPrev;
// insert prev after next
prev->fNext = next->fNext;
next->fNext->fPrev = prev;
next->fNext = prev;
prev->fPrev = next;
}
static void backward_insert_edge_based_on_x(SkAntiEdge* edge SkDECLAREPARAM(int, y)) {
SkFixed x = edge->fFirstX;
for (;;) {
SkAntiEdge* prev = edge->fPrev;
// add 1 to curr_y since we may have added new edges (built from curves)
// that start on the next scanline
SkASSERT(prev && SkFixedFloor(prev->fWalkY - prev->fDXFlipped) <= y + 1);
if (prev->fFirstX <= x) {
break;
}
swap_edges(prev, edge);
}
}
static void insert_new_edges(SkAntiEdge* newEdge, SkFixed curr_y) {
int y = SkFixedFloor(curr_y);
if (SkFixedFloor(newEdge->fWalkY - newEdge->fDXFlipped) < y) {
return;
}
while (SkFixedFloor(newEdge->fWalkY - newEdge->fDXFlipped) == y) {
SkAntiEdge* next = newEdge->fNext;
backward_insert_edge_based_on_x(newEdge SkPARAM(y));
newEdge = next;
}
}
static int find_active_edges(int y, SkAntiEdge** activeLeft,
SkAntiEdge** activeLast) {
SkAntiEdge* first = *activeLeft;
SkFixed bottom = first->fLastY;
SkAntiEdge* active = first->fNext;
first->fLinkSet = false;
SkFixed yLimit = SkIntToFixed(y + 1); // limiting pixel edge
for ( ; active->fWalkY != kEDGE_TAIL_XY; active = active->fNext) {
active->fLinkSet = false;
if (yLimit <= active->fWalkY - active->fDXFlipped) {
break;
}
if ((*activeLeft)->fWalkX > active->fWalkX) {
*activeLeft = active;
}
if (bottom > active->fLastY) {
bottom = active->fLastY;
}
}
*activeLast = active;
return SkFixedCeil(bottom);
}
// All edges are oriented to increase in y. Link edges with common tops and
// bottoms so the links can share their winding sum.
void SkAntiEdgeBuilder::link() {
SkAntiEdge* tail = fEdges.end();
// look for links forwards and backwards
SkAntiEdge* prev = fEdges.begin();
SkAntiEdge* active;
for (active = prev + 1; active != tail; ++active) {
if (prev->fWinding == active->fWinding) {
if (prev->fLastX == active->fFirstX && prev->fLastY == active->fFirstY) {
prev->fLink = active;
active->fLinkSet = true;
} else if (active->fLastX == prev->fFirstX && active->fLastY == prev->fFirstY) {
active->fLink = prev;
prev->fLinkSet = true;
}
}
prev = active;
}
// look for stragglers
prev = fEdges.begin() - 1;
do {
do {
if (++prev == tail) {
return;
}
} while (prev->fLinkSet || NULL != prev->fLink);
for (active = prev + 1; active != tail; ++active) {
if (active->fLinkSet || NULL != active->fLink) {
continue;
}
if (prev->fWinding != active->fWinding) {
continue;
}
if (prev->fLastX == active->fFirstX && prev->fLastY == active->fFirstY) {
prev->fLink = active;
active->fLinkSet = true;
break;
}
if (active->fLastX == prev->fFirstX && active->fLastY == prev->fFirstY) {
active->fLink = prev;
prev->fLinkSet = true;
break;
}
}
} while (true);
}
void SkAntiEdgeBuilder::split(SkAntiEdge* edge, SkFixed y) {
SkPoint upperPoint = {edge->fFirstX, edge->fFirstY};
SkPoint midPoint = {edge->fFirstX + SkMulDiv(y - edge->fFirstY,
edge->fLastX - edge->fFirstX, edge->fLastY - edge->fFirstY), y};
SkPoint lowerPoint = {edge->fLastX, edge->fLastY};
int8_t winding = edge->fWinding;
edge->setLine(upperPoint, midPoint);
edge->fWinding = winding;
SkAntiEdge* lower = fEdges.append();
lower->setLine(midPoint, lowerPoint);
lower->fWinding = winding;
insert_new_edges(lower, y);
}
// An edge computes pixel coverage by considering the integral winding value
// to its left. If an edge is enclosed by fractional winding, split it.
// FIXME: This is also a good time to find crossing edges and split them, too.
void SkAntiEdgeBuilder::split() {
// create a new set of edges that describe the whole link
SkTDArray<SkAntiEdge> links;
SkAntiEdge* first = fHeadEdge.fNext;
SkAntiEdge* active;
for (active = first; active != &fTailEdge; active = active->fNext) {
if (active->fLinkSet || NULL == active->fLink) {
continue;
}
SkAntiEdge* link = links.append();
link->fFirstX = active->fFirstX;
link->fFirstY = active->fFirstY;
SkAntiEdge* linkEnd;
SkAntiEdge* next = active;
do {
linkEnd = next;
next = next->fLink;
} while (NULL != next);
link->fLastX = linkEnd->fLastX;
link->fLastY = linkEnd->fLastY;
}
// create a list of all edges, links and singletons
SkTDArray<SkAntiEdge*> list;
for (active = links.begin(); active != links.end(); ++active) {
*list.append() = active;
}
for (active = first; active != &fTailEdge; active = active->fNext) {
if (!active->fLinkSet && NULL == active->fLink) {
SkAntiEdge* link = links.append();
link->fFirstX = active->fFirstX;
link->fFirstY = active->fFirstY;
link->fLastX = active->fLastX;
link->fLastY = active->fLastY;
*list.append() = link;
}
}
SkAntiEdge tail;
tail.fFirstY = tail.fLastY = kEDGE_TAIL_XY;
*list.append() = &tail;
sort(list);
// walk the list, splitting edges partially occluded on the left
SkAntiEdge* listTop = list[0];
for (active = first; active != &fTailEdge; active = active->fNext) {
while (listTop->fLastY < active->fFirstY) {
listTop = listTop->fNext;
}
for (SkAntiEdge* check = listTop; check->fFirstY < active->fLastY; check = check->fNext) {
if (check->fFirstX > active->fFirstX) {
continue;
}
if (check->fFirstX == active->fFirstX && check->fDX > active->fDX) {
continue;
}
if (check->fFirstY > active->fFirstY) {
split(active, check->fFirstY);
}
if (check->fLastY < active->fLastY) {
split(active, check->fLastY);
}
}
}
}
static inline uint8_t coverage_to_8(int coverage) {
uint16_t x = coverage < 0 ? 0 : coverage > 0xFFFF ? 0xFFFF : coverage;
// for values 0x7FFF and smaller, add (0x7F - high byte) and trunc
// for values 0x8000 and larger, subtract (high byte - 0x80) and trunc
return (x + 0x7f + (x >> 15) - (x >> 8)) >> 8;
}
void SkAntiEdgeBuilder::walk(uint8_t* result, int rowBytes, int height) {
SkAntiEdge* first = fHeadEdge.fNext;
SkFixed top = first->fWalkY - first->fDXFlipped;
int y = SkFixedFloor(top);
do {
SkAntiEdge* activeLeft = first;
SkAntiEdge* activeLast, * active;
int yLast = find_active_edges(y, &activeLeft, &activeLast);
while (y < yLast) {
SkAssertResult(y >= 0);
SkAssertResult(y < height);
SkFixed left = activeLeft->fWalkX;
int x = SkFixedFloor(left);
uint8_t* resultPtr = &result[y * rowBytes + x];
bool finished;
do {
left = SkIntToFixed(x);
SkAssertResult(x >= 0);
// SkAssertResult(x < pixelCol);
if (x >= rowBytes) { // FIXME: cumulative error in fX += fDX
break; // fails to set fFinished early enough
} // see test 6 (dy<dx)
finished = true;
int coverage = 0;
for (active = first; active != activeLast; active = active->fNext) {
if (left + SK_Fixed1 <= active->fX) {
finished = false;
continue; // walker is to the left of edge
}
int cover = active->fDXFlipped ?
active->advanceFlippedX(left) : active->advanceX(left);
if (0 == active->fWindingSum) {
cover = -cover;
}
coverage += cover;
finished &= active->fFinished;
}
uint8_t old = *resultPtr;
uint8_t pix = coverage_to_8(coverage);
uint8_t blend = old > pix ? old : pix;
*resultPtr++ = blend;
++x;
} while (!finished);
++y;
top = SkIntToFixed(y);
SkFixed topLimit = top + SK_Fixed1;
SkFixed xSort = -SK_FixedMax;
for (active = first; active != activeLast; active = active->fNext) {
if (xSort > active->fX || topLimit > active->fLastY) {
yLast = y; // recompute bottom after all Ys are advanced
}
xSort = active->fX;
if (active->fWalkY < active->fLastY) {
active->advanceY(top);
}
}
for (active = first; active != activeLast; ) {
SkAntiEdge* next = active->fNext;
if (top >= active->fLastY) {
remove_edge(active);
}
active = next;
}
first = fHeadEdge.fNext;
}
SkAntiEdge* prev = activeLast->fPrev;
if (prev != &fHeadEdge) {
insert_new_edges(prev, top);
first = fHeadEdge.fNext;
}
} while (first->fWalkY < kEDGE_TAIL_XY);
}
void SkAntiEdgeBuilder::process(const SkPoint* points, int ptCount,
uint8_t* result, int pixelCol, int pixelRow) {
if (ptCount < 3) {
return;
}
int count = build(points, ptCount);
if (count == 0) {
return;
}
SkAssertResult(count > 1);
link();
sort();
split();
calc();
walk(result, pixelCol, pixelRow);
}
////////////////////////////////////////////////////////////////////////////////
int test3by3_test;
// input is a rectangle
static void test_3_by_3() {
const int pixelRow = 3;
const int pixelCol = 3;
const int ptCount = 4;
const int pixelCount = pixelRow * pixelCol;
const SkPoint tests[][ptCount] = {
{{2.0f, 1.0f}, {1.0f, 1.0f}, {1.0f, 2.0f}, {2.0f, 2.0f}}, // 0: full rect
{{2.5f, 1.0f}, {1.5f, 1.0f}, {1.5f, 2.0f}, {2.5f, 2.0f}}, // 1: y edge
{{2.0f, 1.5f}, {1.0f, 1.5f}, {1.0f, 2.5f}, {2.0f, 2.5f}}, // 2: x edge
{{2.5f, 1.5f}, {1.5f, 1.5f}, {1.5f, 2.5f}, {2.5f, 2.5f}}, // 3: x/y edge
{{2.8f, 0.2f}, {0.2f, 0.2f}, {0.2f, 2.8f}, {2.8f, 2.8f}}, // 4: large
{{1.8f, 1.2f}, {1.2f, 1.2f}, {1.2f, 1.8f}, {1.8f, 1.8f}}, // 5: small
{{0.0f, 0.0f}, {0.0f, 1.0f}, {3.0f, 2.0f}, {3.0f, 1.0f}}, // 6: dy<dx
{{3.0f, 0.0f}, {0.0f, 1.0f}, {0.0f, 2.0f}, {3.0f, 1.0f}}, // 7: dy<-dx
{{1.0f, 0.0f}, {0.0f, 0.0f}, {1.0f, 3.0f}, {2.0f, 3.0f}}, // 8: dy>dx
{{2.0f, 0.0f}, {1.0f, 0.0f}, {0.0f, 3.0f}, {1.0f, 3.0f}}, // 9: dy>-dx
{{0.5f, 0.5f}, {0.5f, 1.5f}, {2.5f, 2.5f}, {2.5f, 1.5f}}, // 10: dy<dx 2
{{2.5f, 0.5f}, {0.5f, 1.5f}, {0.5f, 2.5f}, {2.5f, 1.5f}}, // 11: dy<-dx 2
{{0.0f, 0.0f}, {2.0f, 0.0f}, {2.0f, 2.0f}, {0.0f, 2.0f}}, // 12: 2x2
{{0.0f, 0.0f}, {3.0f, 0.0f}, {3.0f, 3.0f}, {0.0f, 3.0f}}, // 13: 3x3
{{1.75f, 0.25f}, {2.75f, 1.25f}, {1.25f, 2.75f}, {0.25f, 1.75f}}, // 14
{{2.25f, 0.25f}, {2.75f, 0.75f}, {0.75f, 2.75f}, {0.25f, 2.25f}}, // 15
{{0.25f, 0.75f}, {0.75f, 0.25f}, {2.75f, 2.25f}, {2.25f, 2.75f}}, // 16
{{1.25f, 0.50f}, {1.75f, 0.25f}, {2.75f, 2.25f}, {2.25f, 2.50f}}, // 17
{{1.00f, 0.75f}, {2.00f, 0.50f}, {2.00f, 1.50f}, {1.00f, 1.75f}}, // 18
{{1.00f, 0.50f}, {2.00f, 0.75f}, {2.00f, 1.75f}, {1.00f, 1.50f}}, // 19
{{1.00f, 0.75f}, {1.00f, 1.75f}, {2.00f, 1.50f}, {2.00f, 0.50f}}, // 20
{{1.00f, 0.50f}, {1.00f, 1.50f}, {2.00f, 1.75f}, {2.00f, 0.75f}}, // 21
};
const uint8_t results[][pixelCount] = {
{0x00, 0x00, 0x00, // 0: 1 pixel rect
0x00, 0xFF, 0x00,
0x00, 0x00, 0x00},
{0x00, 0x00, 0x00, // 1: y edge
0x00, 0x7F, 0x80,
0x00, 0x00, 0x00},
{0x00, 0x00, 0x00, // 2: x edge
0x00, 0x7F, 0x00,
0x00, 0x7F, 0x00},
{0x00, 0x00, 0x00, // 3: x/y edge
0x00, 0x40, 0x40,
0x00, 0x40, 0x40},
{0xA3, 0xCC, 0xA3, // 4: large
0xCC, 0xFF, 0xCC,
0xA3, 0xCC, 0xA3},
{0x00, 0x00, 0x00, // 5: small
0x00, 0x5C, 0x00,
0x00, 0x00, 0x00},
{0xD5, 0x80, 0x2B, // 6: dy<dx
0x2A, 0x7F, 0xD4,
0x00, 0x00, 0x00},
{0x2B, 0x80, 0xD5, // 7: dy<-dx
0xD4, 0x7F, 0x2A,
0x00, 0x00, 0x00},
{0xD5, 0x2A, 0x00, // 8: dy>dx
0x80, 0x7F, 0x00,
0x2B, 0xD4, 0x00},
{0x2A, 0xD5, 0x00, // 9: dy>-dx
0x7F, 0x80, 0x00,
0xD4, 0x2B, 0x00},
{0x30, 0x10, 0x00, // 10: dy<dx 2
0x50, 0xDF, 0x50,
0x00, 0x10, 0x30},
{0x00, 0x10, 0x30, // 11: dy<-dx 2
0x50, 0xDF, 0x50,
0x30, 0x10, 0x00},
{0xFF, 0xFF, 0x00, // 12: 2x2
0xFF, 0xFF, 0x00,
0x00, 0x00, 0x00},
{0xFF, 0xFF, 0xFF, // 13: 3x3
0xFF, 0xFF, 0xFF,
0xFF, 0xFF, 0xFF},
{0x00, 0x70, 0x20, // 14
0x70, 0xFF, 0x70,
0x20, 0x70, 0x00},
{0x00, 0x20, 0x60, // 15
0x20, 0xBF, 0x20,
0x60, 0x20, 0x00},
{0x60, 0x20, 0x00, // 16
0x20, 0xBF, 0x20,
0x00, 0x20, 0x60},
{0x00, 0x60, 0x04, // 17
0x00, 0x40, 0x60,
0x00, 0x00, 0x3C},
{0x00, 0x60, 0x00, // 18
0x00, 0x9F, 0x00,
0x00, 0x00, 0x00},
{0x00, 0x60, 0x00, // 19
0x00, 0x9F, 0x00,
0x00, 0x00, 0x00},
{0x00, 0x60, 0x00, // 20
0x00, 0x9F, 0x00,
0x00, 0x00, 0x00},
{0x00, 0x60, 0x00, // 21
0x00, 0x9F, 0x00,
0x00, 0x00, 0x00},
};
const int testCount = sizeof(tests) / sizeof(tests[0]);
SkAssertResult(testCount == sizeof(results) / sizeof(results[0]));
int testFirst = test3by3_test < 0 ? 0 : test3by3_test;
int testLast = test3by3_test < 0 ? testCount : test3by3_test + 1;
for (int testIndex = testFirst; testIndex < testLast; ++testIndex) {
uint8_t result[pixelRow][pixelCol];
sk_bzero(result, sizeof(result));
const SkPoint* rect = tests[testIndex];
SkAntiEdgeBuilder builder;
builder.process(rect, ptCount, result[0], pixelCol, pixelRow);
SkAssertResult(memcmp(results[testIndex], result[0], pixelCount) == 0);
}
}
// input has arbitrary number of points
static void test_arbitrary_3_by_3() {
const int pixelRow = 3;
const int pixelCol = 3;
const int pixelCount = pixelRow * pixelCol;
const SkPoint t1[] = { {1,1}, {2,1}, {2,1.5f}, {1,1.5f}, {1,2}, {2,2},
{2,1.5f}, {1,1.5f}, {1,1} };
const SkPoint* tests[] = { t1 };
size_t testPts[] = { sizeof(t1) / sizeof(t1[0]) };
const uint8_t results[][pixelCount] = {
{0x00, 0x00, 0x00, // 0: 1 pixel rect
0x00, 0xFF, 0x00,
0x00, 0x00, 0x00},
};
const int testCount = sizeof(tests) / sizeof(tests[0]);
SkAssertResult(testCount == sizeof(results) / sizeof(results[0]));
int testFirst = test3by3_test < 0 ? 0 : test3by3_test;
int testLast = test3by3_test < 0 ? testCount : test3by3_test + 1;
for (int testIndex = testFirst; testIndex < testLast; ++testIndex) {
uint8_t result[pixelRow][pixelCol];
sk_bzero(result, sizeof(result));
const SkPoint* pts = tests[testIndex];
size_t ptCount = testPts[testIndex];
SkAntiEdgeBuilder builder;
builder.process(pts, ptCount, result[0], pixelCol, pixelRow);
SkAssertResult(memcmp(results[testIndex], result[0], pixelCount) == 0);
}
}
#include "SkRect.h"
#include "SkPath.h"
int testsweep_test;
static void create_sweep(uint8_t* result, int pixelRow, int pixelCol, SkScalar rectWidth) {
const int ptCount = 4;
SkRect refRect = {pixelCol / 2 - rectWidth / 2, 5,
pixelCol / 2 + rectWidth / 2, pixelRow / 2 - 5};
SkPath refPath;
refPath.addRect(refRect);
SkScalar angleFirst = testsweep_test < 0 ? 0 : testsweep_test;
SkScalar angleLast = testsweep_test < 0 ? 360 : testsweep_test + 1;
for (SkScalar angle = angleFirst; angle < angleLast; angle += 12) {
SkPath rotPath;
SkMatrix matrix;
matrix.setRotate(angle, SkIntToScalar(pixelCol) / 2,
SkIntToScalar(pixelRow) / 2);
refPath.transform(matrix, &rotPath);
SkPoint rect[ptCount], temp[2];
SkPath::Iter iter(rotPath, false);
int index = 0;
for (;;) {
SkPath::Verb verb = iter.next(temp);
if (verb == SkPath::kMove_Verb) {
continue;
}
if (verb == SkPath::kClose_Verb) {
break;
}
SkAssertResult(SkPath::kLine_Verb == verb);
rect[index++] = temp[0];
}
SkAntiEdgeBuilder builder;
builder.process(rect, ptCount, result, pixelCol, pixelRow);
}
}
static void create_horz(uint8_t* result, int pixelRow, int pixelCol) {
const int ptCount = 4;
for (SkScalar x = 0; x < 100; x += 5) {
SkPoint rect[ptCount];
rect[0].fX = 0; rect[0].fY = x;
rect[1].fX = 100; rect[1].fY = x;
rect[2].fX = 100; rect[2].fY = x + x / 50;
rect[3].fX = 0; rect[3].fY = x + x / 50;
SkAntiEdgeBuilder builder;
builder.process(rect, ptCount, result, pixelCol, pixelRow);
}
}
static void create_vert(uint8_t* result, int pixelRow, int pixelCol) {
const int ptCount = 4;
for (SkScalar x = 0; x < 100; x += 5) {
SkPoint rect[ptCount];
rect[0].fY = 0; rect[0].fX = x;
rect[1].fY = 100; rect[1].fX = x;
rect[2].fY = 100; rect[2].fX = x + x / 50;
rect[3].fY = 0; rect[3].fX = x + x / 50;
SkAntiEdgeBuilder builder;
builder.process(rect, ptCount, result, pixelCol, pixelRow);
}
}
static void create_angle(uint8_t* result, int pixelRow, int pixelCol, SkScalar angle) {
const int ptCount = 4;
SkRect refRect = {25, 25, 125, 125};
SkPath refPath;
for (SkScalar x = 30; x < 125; x += 5) {
refRect.fTop = x;
refRect.fBottom = x + (x - 25) / 50;
refPath.addRect(refRect);
}
SkPath rotPath;
SkMatrix matrix;
matrix.setRotate(angle, 75, 75);
refPath.transform(matrix, &rotPath);
SkPath::Iter iter(rotPath, false);
for (SkScalar x = 30; x < 125; x += 5) {
SkPoint rect[ptCount], temp[2];
int index = 0;
for (;;) {
SkPath::Verb verb = iter.next(temp);
if (verb == SkPath::kMove_Verb) {
continue;
}
if (verb == SkPath::kClose_Verb) {
break;
}
SkAssertResult(SkPath::kLine_Verb == verb);
rect[index++] = temp[0];
}
// if ((x == 30 || x == 75) && angle == 12) continue;
SkAntiEdgeBuilder builder;
builder.process(rect, ptCount, result, pixelCol, pixelRow);
}
}
static void test_sweep() {
const int pixelRow = 100;
const int pixelCol = 100;
uint8_t result[pixelRow][pixelCol];
sk_bzero(result, sizeof(result));
create_sweep(result[0], pixelRow, pixelCol, 1);
}
static void test_horz() {
const int pixelRow = 100;
const int pixelCol = 100;
uint8_t result[pixelRow][pixelCol];
sk_bzero(result, sizeof(result));
create_horz(result[0], pixelRow, pixelCol);
}
static void test_vert() {
const int pixelRow = 100;
const int pixelCol = 100;
uint8_t result[pixelRow][pixelCol];
sk_bzero(result, sizeof(result));
create_vert(result[0], pixelRow, pixelCol);
}
static void test_angle(SkScalar angle) {
const int pixelRow = 150;
const int pixelCol = 150;
uint8_t result[pixelRow][pixelCol];
sk_bzero(result, sizeof(result));
create_angle(result[0], pixelRow, pixelCol, angle);
}
#include "SkBitmap.h"
void CreateSweep(SkBitmap* sweep, SkScalar rectWidth) {
const int pixelRow = 100;
const int pixelCol = 100;
sweep->setConfig(SkBitmap::kA8_Config, pixelCol, pixelRow);
sweep->allocPixels();
sweep->eraseColor(SK_ColorTRANSPARENT);
sweep->lockPixels();
void* pixels = sweep->getPixels();
create_sweep((uint8_t*) pixels, pixelRow, pixelCol, rectWidth);
sweep->unlockPixels();
}
void CreateHorz(SkBitmap* sweep) {
const int pixelRow = 100;
const int pixelCol = 100;
sweep->setConfig(SkBitmap::kA8_Config, pixelCol, pixelRow);
sweep->allocPixels();
sweep->eraseColor(SK_ColorTRANSPARENT);
sweep->lockPixels();
void* pixels = sweep->getPixels();
create_horz((uint8_t*) pixels, pixelRow, pixelCol);
sweep->unlockPixels();
}
void CreateVert(SkBitmap* sweep) {
const int pixelRow = 100;
const int pixelCol = 100;
sweep->setConfig(SkBitmap::kA8_Config, pixelCol, pixelRow);
sweep->allocPixels();
sweep->eraseColor(SK_ColorTRANSPARENT);
sweep->lockPixels();
void* pixels = sweep->getPixels();
create_vert((uint8_t*) pixels, pixelRow, pixelCol);
sweep->unlockPixels();
}
void CreateAngle(SkBitmap* sweep, SkScalar angle) {
const int pixelRow = 150;
const int pixelCol = 150;
sweep->setConfig(SkBitmap::kA8_Config, pixelCol, pixelRow);
sweep->allocPixels();
sweep->eraseColor(SK_ColorTRANSPARENT);
sweep->lockPixels();
void* pixels = sweep->getPixels();
create_angle((uint8_t*) pixels, pixelRow, pixelCol, angle);
sweep->unlockPixels();
}
#include "SkCanvas.h"
static void testPng() {
SkBitmap device;
device.setConfig(SkBitmap::kARGB_8888_Config, 4, 4);
device.allocPixels();
device.eraseColor(0xFFFFFFFF);
SkCanvas canvas(device);
canvas.drawARGB(167, 0, 0, 0);
device.lockPixels();
unsigned char* pixels = (unsigned char*) device.getPixels();
SkDebugf("%02x%02x%02x%02x", pixels[3], pixels[2], pixels[1], pixels[0]);
}
void SkAntiEdge_Test() {
testPng();
test_arbitrary_3_by_3();
test_angle(12);
#if 0
test3by3_test = 18;
#else
test3by3_test = -1;
#endif
#if 0
testsweep_test = 7 * 12;
#else
testsweep_test = -1;
#endif
if (testsweep_test == -1) {
test_3_by_3();
}
test_sweep();
test_horz();
test_vert();
}
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