skia2/gm/convex_all_line_paths.cpp
Brian Salomon 8e449ebec3 Fix GrAAConvexTessellator to handle cases slightly concave bistectors.
When repeatedly insetting rings we can wind up with bisector vectors
that correspond to a slightly concave ring. This would cause the first
intersection when computing the next ring's inset depth to be outside
the current ring. Instead skip adjacent bisectors that intersect outside
the ring during the search.

Change-Id: I3efab5a9f44966888cfa86715876b7b177950732
Reviewed-on: https://skia-review.googlesource.com/151827
Reviewed-by: Robert Phillips <robertphillips@google.com>
Commit-Queue: Brian Salomon <bsalomon@google.com>
2018-09-05 19:46:30 +00:00

405 lines
12 KiB
C++

/*
* Copyright 2015 Google Inc.
*
* Use of this source code is governed by a BSD-style license that can be
* found in the LICENSE file.
*/
#include "gm.h"
#include "SkPolyUtils.h"
#include "SkPathPriv.h"
static void create_ngon(int n, SkPoint* pts, SkScalar width, SkScalar height) {
float angleStep = 360.0f / n, angle = 0.0f, sin, cos;
if ((n % 2) == 1) {
angle = angleStep/2.0f;
}
for (int i = 0; i < n; ++i) {
sin = SkScalarSinCos(SkDegreesToRadians(angle), &cos);
pts[i].fX = -sin * width;
pts[i].fY = cos * height;
angle += angleStep;
}
}
namespace ConvexLineOnlyData {
// narrow rect
const SkPoint gPoints0[] = {
{ -1.5f, -50.0f },
{ 1.5f, -50.0f },
{ 1.5f, 50.0f },
{ -1.5f, 50.0f }
};
// narrow rect on an angle
const SkPoint gPoints1[] = {
{ -50.0f, -49.0f },
{ -49.0f, -50.0f },
{ 50.0f, 49.0f },
{ 49.0f, 50.0f }
};
// trap - narrow on top - wide on bottom
const SkPoint gPoints2[] = {
{ -10.0f, -50.0f },
{ 10.0f, -50.0f },
{ 50.0f, 50.0f },
{ -50.0f, 50.0f }
};
// wide skewed rect
const SkPoint gPoints3[] = {
{ -50.0f, -50.0f },
{ 0.0f, -50.0f },
{ 50.0f, 50.0f },
{ 0.0f, 50.0f }
};
// thin rect with colinear-ish lines
const SkPoint gPoints4[] = {
{ -6.0f, -50.0f },
{ 4.0f, -50.0f },
{ 5.0f, -25.0f },
{ 6.0f, 0.0f },
{ 5.0f, 25.0f },
{ 4.0f, 50.0f },
{ -4.0f, 50.0f }
};
// degenerate
const SkPoint gPoints5[] = {
{ -0.025f, -0.025f },
{ 0.025f, -0.025f },
{ 0.025f, 0.025f },
{ -0.025f, 0.025f }
};
// Triangle in which the first point should fuse with last
const SkPoint gPoints6[] = {
{ -20.0f, -13.0f },
{ -20.0f, -13.05f },
{ 20.0f, -13.0f },
{ 20.0f, 27.0f }
};
// thin rect with colinear lines
const SkPoint gPoints7[] = {
{ -10.0f, -50.0f },
{ 10.0f, -50.0f },
{ 10.0f, -25.0f },
{ 10.0f, 0.0f },
{ 10.0f, 25.0f },
{ 10.0f, 50.0f },
{ -10.0f, 50.0f }
};
// capped teardrop
const SkPoint gPoints8[] = {
{ 50.00f, 50.00f },
{ 0.00f, 50.00f },
{ -15.45f, 47.55f },
{ -29.39f, 40.45f },
{ -40.45f, 29.39f },
{ -47.55f, 15.45f },
{ -50.00f, 0.00f },
{ -47.55f, -15.45f },
{ -40.45f, -29.39f },
{ -29.39f, -40.45f },
{ -15.45f, -47.55f },
{ 0.00f, -50.00f },
{ 50.00f, -50.00f }
};
// teardrop
const SkPoint gPoints9[] = {
{ 4.39f, 40.45f },
{ -9.55f, 47.55f },
{ -25.00f, 50.00f },
{ -40.45f, 47.55f },
{ -54.39f, 40.45f },
{ -65.45f, 29.39f },
{ -72.55f, 15.45f },
{ -75.00f, 0.00f },
{ -72.55f, -15.45f },
{ -65.45f, -29.39f },
{ -54.39f, -40.45f },
{ -40.45f, -47.55f },
{ -25.0f, -50.0f },
{ -9.55f, -47.55f },
{ 4.39f, -40.45f },
{ 75.00f, 0.00f }
};
// clipped triangle
const SkPoint gPoints10[] = {
{ -10.0f, -50.0f },
{ 10.0f, -50.0f },
{ 50.0f, 31.0f },
{ 40.0f, 50.0f },
{ -40.0f, 50.0f },
{ -50.0f, 31.0f },
};
const SkPoint* gPoints[] = {
gPoints0, gPoints1, gPoints2, gPoints3, gPoints4, gPoints5, gPoints6,
gPoints7, gPoints8, gPoints9, gPoints10,
};
const size_t gSizes[] = {
SK_ARRAY_COUNT(gPoints0),
SK_ARRAY_COUNT(gPoints1),
SK_ARRAY_COUNT(gPoints2),
SK_ARRAY_COUNT(gPoints3),
SK_ARRAY_COUNT(gPoints4),
SK_ARRAY_COUNT(gPoints5),
SK_ARRAY_COUNT(gPoints6),
SK_ARRAY_COUNT(gPoints7),
SK_ARRAY_COUNT(gPoints8),
SK_ARRAY_COUNT(gPoints9),
SK_ARRAY_COUNT(gPoints10),
};
static_assert(SK_ARRAY_COUNT(gSizes) == SK_ARRAY_COUNT(gPoints), "array_mismatch");
}
namespace skiagm {
// This GM is intended to exercise Ganesh's handling of convex line-only
// paths
class ConvexLineOnlyPathsGM : public GM {
public:
ConvexLineOnlyPathsGM(bool doStrokeAndFill) : fDoStrokeAndFill(doStrokeAndFill) {
this->setBGColor(0xFFFFFFFF);
}
protected:
SkString onShortName() override {
if (fDoStrokeAndFill) {
return SkString("convex-lineonly-paths-stroke-and-fill");
}
return SkString("convex-lineonly-paths");
}
SkISize onISize() override { return SkISize::Make(kGMWidth, kGMHeight); }
bool runAsBench() const override { return true; }
static SkPath GetPath(int index, SkPath::Direction dir) {
std::unique_ptr<SkPoint[]> data(nullptr);
const SkPoint* points;
int numPts;
if (index < (int) SK_ARRAY_COUNT(ConvexLineOnlyData::gPoints)) {
// manually specified
points = ConvexLineOnlyData::gPoints[index];
numPts = (int)ConvexLineOnlyData::gSizes[index];
} else {
// procedurally generated
SkScalar width = kMaxPathHeight/2;
SkScalar height = kMaxPathHeight/2;
switch (index-SK_ARRAY_COUNT(ConvexLineOnlyData::gPoints)) {
case 0:
numPts = 3;
break;
case 1:
numPts = 4;
break;
case 2:
numPts = 5;
break;
case 3: // squashed pentagon
numPts = 5;
width = kMaxPathHeight/5;
break;
case 4:
numPts = 6;
break;
case 5:
numPts = 8;
break;
case 6: // squashed octogon
numPts = 8;
width = kMaxPathHeight/5;
break;
case 7:
numPts = 20;
break;
case 8:
numPts = 100;
break;
default:
numPts = 3;
break;
}
data.reset(new SkPoint[numPts]);
create_ngon(numPts, data.get(), width, height);
points = data.get();
}
SkPath path;
if (SkPath::kCW_Direction == dir) {
path.moveTo(points[0]);
for (int i = 1; i < numPts; ++i) {
path.lineTo(points[i]);
}
} else {
path.moveTo(points[numPts-1]);
for (int i = numPts-2; i >= 0; --i) {
path.lineTo(points[i]);
}
}
path.close();
#ifdef SK_DEBUG
// Each path this method returns should be convex, only composed of
// lines, wound the right direction, and short enough to fit in one
// of the GMs rows.
SkASSERT(path.isConvex());
SkASSERT(SkPath::kLine_SegmentMask == path.getSegmentMasks());
SkPathPriv::FirstDirection actualDir;
SkASSERT(SkPathPriv::CheapComputeFirstDirection(path, &actualDir));
SkASSERT(SkPathPriv::AsFirstDirection(dir) == actualDir);
SkRect bounds = path.getBounds();
SkASSERT(SkScalarNearlyEqual(bounds.centerX(), 0.0f));
SkASSERT(bounds.height() <= kMaxPathHeight);
#endif
return path;
}
// Draw a single path several times, shrinking it, flipping its direction
// and changing its start vertex each time.
void drawPath(SkCanvas* canvas, int index, SkPoint* offset) {
SkPoint center;
{
SkPath path = GetPath(index, SkPath::kCW_Direction);
if (offset->fX+path.getBounds().width() > kGMWidth) {
offset->fX = 0;
offset->fY += kMaxPathHeight;
if (fDoStrokeAndFill) {
offset->fX += kStrokeWidth / 2.0f;
offset->fY += kStrokeWidth / 2.0f;
}
}
center = { offset->fX + SkScalarHalf(path.getBounds().width()), offset->fY};
offset->fX += path.getBounds().width();
if (fDoStrokeAndFill) {
offset->fX += kStrokeWidth;
}
}
const SkColor colors[2] = { SK_ColorBLACK, SK_ColorWHITE };
const SkPath::Direction dirs[2] = { SkPath::kCW_Direction, SkPath::kCCW_Direction };
const float scales[] = { 1.0f, 0.75f, 0.5f, 0.25f, 0.1f, 0.01f, 0.001f };
const SkPaint::Join joins[3] = { SkPaint::kRound_Join,
SkPaint::kBevel_Join,
SkPaint::kMiter_Join };
SkPaint paint;
paint.setAntiAlias(true);
for (size_t i = 0; i < SK_ARRAY_COUNT(scales); ++i) {
SkPath path = GetPath(index, dirs[i%2]);
if (fDoStrokeAndFill) {
paint.setStyle(SkPaint::kStrokeAndFill_Style);
paint.setStrokeJoin(joins[i%3]);
paint.setStrokeWidth(SkIntToScalar(kStrokeWidth));
}
canvas->save();
canvas->translate(center.fX, center.fY);
canvas->scale(scales[i], scales[i]);
paint.setColor(colors[i%2]);
canvas->drawPath(path, paint);
canvas->restore();
}
}
void onDraw(SkCanvas* canvas) override {
// the right edge of the last drawn path
SkPoint offset = { 0, SkScalarHalf(kMaxPathHeight) };
if (fDoStrokeAndFill) {
offset.fX += kStrokeWidth / 2.0f;
offset.fY += kStrokeWidth / 2.0f;
}
for (int i = 0; i < kNumPaths; ++i) {
this->drawPath(canvas, i, &offset);
}
{
// Repro for crbug.com/472723 (Missing AA on portions of graphic with GPU rasterization)
SkPaint p;
p.setAntiAlias(true);
if (fDoStrokeAndFill) {
p.setStyle(SkPaint::kStrokeAndFill_Style);
p.setStrokeJoin(SkPaint::kMiter_Join);
p.setStrokeWidth(SkIntToScalar(kStrokeWidth));
}
SkPath p1;
p1.moveTo(60.8522949f, 364.671021f);
p1.lineTo(59.4380493f, 364.671021f);
p1.lineTo(385.414276f, 690.647217f);
p1.lineTo(386.121399f, 689.940125f);
canvas->save();
canvas->translate(356.0f, 50.0f);
canvas->drawPath(p1, p);
canvas->restore();
// Repro for crbug.com/869172 (SVG path incorrectly simplified when using GPU
// Rasterization). This will only draw anything in the stroke-and-fill version.
SkPath p2;
p2.moveTo(10.f, 0.f);
p2.lineTo(38.f, 0.f);
p2.lineTo(66.f, 0.f);
p2.lineTo(94.f, 0.f);
p2.lineTo(122.f, 0.f);
p2.lineTo(150.f, 0.f);
p2.lineTo(150.f, 0.f);
p2.lineTo(122.f, 0.f);
p2.lineTo(94.f, 0.f);
p2.lineTo(66.f, 0.f);
p2.lineTo(38.f, 0.f);
p2.lineTo(10.f, 0.f);
p2.close();
canvas->save();
canvas->translate(0.0f, 500.0f);
canvas->drawPath(p2, p);
canvas->restore();
// Repro for crbug.com/856137. This path previously caused GrAAConvexTessellator to turn
// inset rings into outsets when adjacent bisector angles converged outside the previous
// ring due to accumulated error.
SkPath p3;
p3.setFillType(SkPath::kEvenOdd_FillType);
p3.moveTo(1184.96f, 982.557f);
p3.lineTo(1183.71f, 982.865f);
p3.lineTo(1180.99f, 982.734f);
p3.lineTo(1178.5f, 981.541f);
p3.lineTo(1176.35f, 979.367f);
p3.lineTo(1178.94f, 938.854f);
p3.lineTo(1181.35f, 936.038f);
p3.lineTo(1183.96f, 934.117f);
p3.lineTo(1186.67f, 933.195f);
p3.lineTo(1189.36f, 933.342f);
p3.lineTo(1191.58f, 934.38f);
p3.close();
canvas->save();
SkMatrix m;
m.setAll(0.0893210843f, 0, 79.1197586f, 0, 0.0893210843f, 300, 0, 0, 1);
canvas->concat(m);
canvas->drawPath(p3, p);
canvas->restore();
}
}
private:
static constexpr int kStrokeWidth = 10;
static constexpr int kNumPaths = 20;
static constexpr int kMaxPathHeight = 100;
static constexpr int kGMWidth = 512;
static constexpr int kGMHeight = 512;
bool fDoStrokeAndFill;
typedef GM INHERITED;
};
//////////////////////////////////////////////////////////////////////////////
DEF_GM(return new ConvexLineOnlyPathsGM(false);)
DEF_GM(return new ConvexLineOnlyPathsGM(true);)
}