skia2/gm/hairlines.cpp

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/*
* Copyright 2013 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 "SkCanvas.h"
#include "SkPath.h"
#include "SkTArray.h"
namespace skiagm {
class HairlinesGM : public GM {
protected:
SkString onShortName() override {
return SkString("hairlines");
}
SkISize onISize() override { return SkISize::Make(1250, 1250); }
void onOnceBeforeDraw() override {
{
SkPath* lineAnglesPath = &fPaths.push_back();
enum {
kNumAngles = 15,
kRadius = 40,
};
for (int i = 0; i < kNumAngles; ++i) {
SkScalar angle = SK_ScalarPI * SkIntToScalar(i) / kNumAngles;
SkScalar x = kRadius * SkScalarCos(angle);
SkScalar y = kRadius * SkScalarSin(angle);
lineAnglesPath->moveTo(x, y);
lineAnglesPath->lineTo(-x, -y);
}
}
{
SkPath* kindaTightQuad = &fPaths.push_back();
kindaTightQuad->moveTo(0, -10 * SK_Scalar1);
kindaTightQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), -10 * SK_Scalar1, 0);
}
{
SkPath* tightQuad = &fPaths.push_back();
tightQuad->moveTo(0, -5 * SK_Scalar1);
tightQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), -5 * SK_Scalar1, 0);
}
{
SkPath* tighterQuad = &fPaths.push_back();
tighterQuad->moveTo(0, -2 * SK_Scalar1);
tighterQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), -2 * SK_Scalar1, 0);
}
{
SkPath* unevenTighterQuad = &fPaths.push_back();
unevenTighterQuad->moveTo(0, -1 * SK_Scalar1);
SkPoint p;
p.set(-2 * SK_Scalar1 + 3 * SkIntToScalar(102) / 4, SkIntToScalar(75));
unevenTighterQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), p.fX, p.fY);
}
{
SkPath* reallyTightQuad = &fPaths.push_back();
reallyTightQuad->moveTo(0, -1 * SK_Scalar1);
reallyTightQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), -1 * SK_Scalar1, 0);
}
{
SkPath* closedQuad = &fPaths.push_back();
closedQuad->moveTo(0, -0);
closedQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100), 0, 0);
}
{
SkPath* unevenClosedQuad = &fPaths.push_back();
unevenClosedQuad->moveTo(0, -0);
unevenClosedQuad->quadTo(SkIntToScalar(100), SkIntToScalar(100),
SkIntToScalar(75), SkIntToScalar(75));
}
// Two problem cases for gpu hairline renderer found by shapeops testing. These used
// to assert that the computed bounding box didn't contain all the vertices.
{
SkPath* problem1 = &fPaths.push_back();
problem1->moveTo(SkIntToScalar(4), SkIntToScalar(6));
problem1->cubicTo(SkIntToScalar(5), SkIntToScalar(6),
SkIntToScalar(5), SkIntToScalar(4),
SkIntToScalar(4), SkIntToScalar(0));
problem1->close();
}
{
SkPath* problem2 = &fPaths.push_back();
problem2->moveTo(SkIntToScalar(5), SkIntToScalar(1));
problem2->lineTo(4.32787323f, 1.67212653f);
problem2->cubicTo(2.75223875f, 3.24776125f,
3.00581908f, 4.51236057f,
3.7580452f, 4.37367964f);
problem2->cubicTo(4.66472578f, 3.888381f,
5.f, 2.875f,
5.f, 1.f);
problem2->close();
}
// Three paths that show the same bug (missing end caps)
{
// A caret (crbug.com/131770)
SkPath* bug0 = &fPaths.push_back();
bug0->moveTo(6.5f,5.5f);
bug0->lineTo(3.5f,0.5f);
bug0->moveTo(0.5f,5.5f);
bug0->lineTo(3.5f,0.5f);
}
{
// An X (crbug.com/137317)
SkPath* bug1 = &fPaths.push_back();
bug1->moveTo(1, 1);
bug1->lineTo(6, 6);
bug1->moveTo(1, 6);
bug1->lineTo(6, 1);
}
{
// A right angle (crbug.com/137465 and crbug.com/256776)
SkPath* bug2 = &fPaths.push_back();
bug2->moveTo(5.5f, 5.5f);
bug2->lineTo(5.5f, 0.5f);
bug2->lineTo(0.5f, 0.5f);
}
{
// Arc example to test imperfect truncation bug (crbug.com/295626)
constexpr SkScalar kRad = SkIntToScalar(2000);
constexpr SkScalar kStartAngle = 262.59717f;
constexpr SkScalar kSweepAngle = SkScalarHalf(17.188717f);
SkPath* bug = &fPaths.push_back();
// Add a circular arc
SkRect circle = SkRect::MakeLTRB(-kRad, -kRad, kRad, kRad);
bug->addArc(circle, kStartAngle, kSweepAngle);
// Now add the chord that should cap the circular arc
SkScalar cosV, sinV = SkScalarSinCos(SkDegreesToRadians(kStartAngle), &cosV);
SkPoint p0 = SkPoint::Make(kRad * cosV, kRad * sinV);
sinV = SkScalarSinCos(SkDegreesToRadians(kStartAngle + kSweepAngle), &cosV);
SkPoint p1 = SkPoint::Make(kRad * cosV, kRad * sinV);
bug->moveTo(p0);
bug->lineTo(p1);
}
}
void onDraw(SkCanvas* canvas) override {
constexpr SkAlpha kAlphaValue[] = { 0xFF, 0x40 };
constexpr SkScalar kWidths[] = { 0, 0.5f, 1.5f };
enum {
kMargin = 5,
};
int wrapX = 1250 - kMargin;
SkScalar maxH = 0;
canvas->translate(SkIntToScalar(kMargin), SkIntToScalar(kMargin));
canvas->save();
SkScalar x = SkIntToScalar(kMargin);
for (int p = 0; p < fPaths.count(); ++p) {
for (size_t a = 0; a < SK_ARRAY_COUNT(kAlphaValue); ++a) {
for (int aa = 0; aa < 2; ++aa) {
for (size_t w = 0; w < SK_ARRAY_COUNT(kWidths); w++) {
const SkRect& bounds = fPaths[p].getBounds();
if (x + bounds.width() > wrapX) {
canvas->restore();
canvas->translate(0, maxH + SkIntToScalar(kMargin));
canvas->save();
maxH = 0;
x = SkIntToScalar(kMargin);
}
SkPaint paint;
paint.setARGB(kAlphaValue[a], 0, 0, 0);
paint.setAntiAlias(SkToBool(aa));
paint.setStyle(SkPaint::kStroke_Style);
paint.setStrokeWidth(kWidths[w]);
canvas->save();
canvas->translate(-bounds.fLeft, -bounds.fTop);
canvas->drawPath(fPaths[p], paint);
canvas->restore();
maxH = SkMaxScalar(maxH, bounds.height());
SkScalar dx = bounds.width() + SkIntToScalar(kMargin);
x += dx;
canvas->translate(dx, 0);
}
}
}
}
canvas->restore();
}
private:
SkTArray<SkPath> fPaths;
typedef GM INHERITED;
};
static void draw_squarehair_tests(SkCanvas* canvas, SkScalar width, SkPaint::Cap cap, bool aa) {
SkPaint paint;
paint.setStrokeCap(cap);
paint.setStrokeWidth(width);
paint.setAntiAlias(aa);
paint.setStyle(SkPaint::kStroke_Style);
canvas->drawLine(10, 10, 20, 10, paint);
canvas->drawLine(30, 10, 30, 20, paint);
canvas->drawLine(40, 10, 50, 20, paint);
SkPath path;
path.moveTo(60, 10);
path.quadTo(60, 20, 70, 20);
path.conicTo(70, 10, 80, 10, 0.707f);
canvas->drawPath(path, paint);
path.reset();
path.moveTo(90, 10);
path.cubicTo(90, 20, 100, 20, 100, 10);
path.lineTo(110, 10);
canvas->drawPath(path, paint);
canvas->translate(0, 30);
}
DEF_SIMPLE_GM(squarehair, canvas, 240, 360) {
const bool aliases[] = { false, true };
const SkScalar widths[] = { 0, 0.999f, 1, 1.001f };
const SkPaint::Cap caps[] = { SkPaint::kButt_Cap, SkPaint::kSquare_Cap, SkPaint::kRound_Cap };
for (auto alias : aliases) {
canvas->save();
for (auto width : widths) {
for (auto cap : caps) {
draw_squarehair_tests(canvas, width, cap, alias);
}
}
canvas->restore();
canvas->translate(120, 0);
}
}
//////////////////////////////////////////////////////////////////////////////
static GM* MyFactory(void*) { return new HairlinesGM; }
static GMRegistry reg(MyFactory);
}