Google Git Google Git
Sign in
skia/skia.git/ed0a9a175b53ee9792f2acdcafe4000f7d919aff/./gm/gradients.cpp
blob: 18e5b8a8e877e1097896c9644f92171a6a7fb60e [file]
/*
* 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 "gm/gm.h"
#include "include/core/SkBlendMode.h"
#include "include/core/SkCanvas.h"
#include "include/core/SkColor.h"
#include "include/core/SkColorSpace.h"
#include "include/core/SkFont.h"
#include "include/core/SkMatrix.h"
#include "include/core/SkPaint.h"
#include "include/core/SkPicture.h"
#include "include/core/SkPictureRecorder.h"
#include "include/core/SkPoint.h"
#include "include/core/SkRect.h"
#include "include/core/SkRefCnt.h"
#include "include/core/SkScalar.h"
#include "include/core/SkShader.h"
#include "include/core/SkSize.h"
#include "include/core/SkString.h"
#include "include/core/SkTileMode.h"
#include "include/core/SkTypes.h"
#include "include/effects/SkGradient.h"
#include "include/private/SkAssert.h"
#include "include/private/SkFloatingPoint.h"
#include "src/core/SkColorPriv.h"
#include "tools/ToolUtils.h"
#include "tools/fonts/FontToolUtils.h"
#include <array>
#include <initializer_list>
#include <math.h>
namespace {
struct GradData {
SkSpan<const SkColor4f> fColors;
SkSpan<const float> fPos;
};
constexpr SkColor4f gColors[] ={
SkColors::kRed,
SkColors::kGreen,
SkColors::kBlue,
SkColors::kWhite,
SkColors::kBlack,
};
constexpr SkScalar gPos0[] = { 0, SK_Scalar1 };
constexpr SkScalar gPos1[] = { SK_Scalar1/4, SK_Scalar1*3/4 };
constexpr SkScalar gPos2[] = {
0, SK_Scalar1/8, SK_Scalar1/2, SK_Scalar1*7/8, SK_Scalar1
};
constexpr SkScalar gPosClamp[] = {0.0f, 0.0f, 1.0f, 1.0f};
constexpr SkColor4f gColor4fClamp[] = {
SkColors::kRed,
SkColors::kGreen,
SkColors::kGreen,
SkColors::kBlue,
};
static constexpr auto gGradData = std::to_array<GradData>({
GradData{ {gColors, 2}, {}},
GradData{ {gColors, 2}, gPos0},
GradData{ {gColors, 2}, gPos1},
GradData{ {gColors, 5}, {}},
GradData{ {gColors, 5}, gPos2},
GradData{gColor4fClamp, gPosClamp}
});
static sk_sp<SkShader> MakeLinear(const SkPoint pts[2], const GradData& data,
SkTileMode tm, const SkMatrix& localMatrix) {
return SkShaders::LinearGradient(pts, {{data.fColors, data.fPos, tm}, {}}, &localMatrix);
}
static sk_sp<SkShader> MakeRadial(const SkPoint pts[2], const GradData& data,
SkTileMode tm, const SkMatrix& localMatrix) {
SkPoint center;
center.set(sk_float_midpoint(pts[0].fX, pts[1].fX),
sk_float_midpoint(pts[0].fY, pts[1].fY));
return SkShaders::RadialGradient(center, center.fX, {{data.fColors, data.fPos, tm}, {}},
&localMatrix);
}
static sk_sp<SkShader> MakeSweep(const SkPoint pts[2], const GradData& data,
SkTileMode tm, const SkMatrix& localMatrix) {
SkPoint center;
center.set(sk_float_midpoint(pts[0].fX, pts[1].fX),
sk_float_midpoint(pts[0].fY, pts[1].fY));
return SkShaders::SweepGradient(center, {{data.fColors, data.fPos, tm}, {}}, &localMatrix);
}
static sk_sp<SkShader> Make2Radial(const SkPoint pts[2], const GradData& data,
SkTileMode tm, const SkMatrix& localMatrix) {
SkPoint center0, center1;
center0.set(sk_float_midpoint(pts[0].fX, pts[1].fX),
sk_float_midpoint(pts[0].fY, pts[1].fY));
center1.set(SkScalarInterp(pts[0].fX, pts[1].fX, SkIntToScalar(3)/5),
SkScalarInterp(pts[0].fY, pts[1].fY, SkIntToScalar(1)/4));
return SkShaders::TwoPointConicalGradient(center1, (pts[1].fX - pts[0].fX) / 7,
center0, (pts[1].fX - pts[0].fX) / 2,
{{data.fColors, data.fPos, tm}, {}}, &localMatrix);
}
static sk_sp<SkShader> Make2Conical(const SkPoint pts[2], const GradData& data,
SkTileMode tm, const SkMatrix& localMatrix) {
SkPoint center0, center1;
SkScalar radius0 = (pts[1].fX - pts[0].fX) / 10;
SkScalar radius1 = (pts[1].fX - pts[0].fX) / 3;
center0.set(pts[0].fX + radius0, pts[0].fY + radius0);
center1.set(pts[1].fX - radius1, pts[1].fY - radius1);
return SkShaders::TwoPointConicalGradient(center1, radius1, center0, radius0,
{{data.fColors, data.fPos, tm}, {}}, &localMatrix);
}
typedef sk_sp<SkShader> (*GradMaker)(const SkPoint pts[2], const GradData& data,
SkTileMode tm, const SkMatrix& localMatrix);
static constexpr auto gGradMakers = std::to_array<GradMaker>({
MakeLinear,
MakeRadial,
MakeSweep,
Make2Radial,
Make2Conical,
});
///////////////////////////////////////////////////////////////////////////////
class GradientsGM : public skiagm::GM {
public:
GradientsGM(bool dither) : fDither(dither) {}
protected:
const bool fDither;
void onDraw(SkCanvas* canvas) override {
SkPoint pts[2] = {
{ 0, 0 },
{ SkIntToScalar(100), SkIntToScalar(100) }
};
SkTileMode tm = SkTileMode::kClamp;
SkRect r = { 0, 0, SkIntToScalar(100), SkIntToScalar(100) };
SkPaint paint;
paint.setAntiAlias(true);
paint.setDither(fDither);
canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
for (size_t i = 0; i < std::size(gGradData); i++) {
canvas->save();
for (size_t j = 0; j < std::size(gGradMakers); j++) {
SkMatrix scale = SkMatrix::I();
if (i == 5) { // if the clamp case
scale.setScale(0.5f, 0.5f);
scale.postTranslate(25.f, 25.f);
}
paint.setShader(gGradMakers[j](pts, gGradData[i], tm, scale));
canvas->drawRect(r, paint);
canvas->translate(0, SkIntToScalar(120));
}
canvas->restore();
canvas->translate(SkIntToScalar(120), 0);
}
}
private:
void onOnceBeforeDraw() override { this->setBGColor(0xFFDDDDDD); }
SkString getName() const override {
return SkString(fDither ? "gradients" : "gradients_nodither");
}
SkISize getISize() override { return {840, 815}; }
};
DEF_GM( return new GradientsGM(true); )
DEF_GM( return new GradientsGM(false); )
// Based on the original gradient slide, but with perspective applied to the
// gradient shaders' local matrices
class GradientsLocalPerspectiveGM : public skiagm::GM {
public:
GradientsLocalPerspectiveGM(bool dither) : fDither(dither) {
this->setBGColor(0xFFDDDDDD);
}
private:
SkString getName() const override {
return SkString(fDither ? "gradients_local_perspective" :
"gradients_local_perspective_nodither");
}
SkISize getISize() override { return {840, 815}; }
void onDraw(SkCanvas* canvas) override {
SkPoint pts[2] = {
{ 0, 0 },
{ SkIntToScalar(100), SkIntToScalar(100) }
};
SkTileMode tm = SkTileMode::kClamp;
SkRect r = { 0, 0, SkIntToScalar(100), SkIntToScalar(100) };
SkPaint paint;
paint.setAntiAlias(true);
paint.setDither(fDither);
canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
for (size_t i = 0; i < std::size(gGradData); i++) {
canvas->save();
for (size_t j = 0; j < std::size(gGradMakers); j++) {
// apply an increasing y perspective as we move to the right
SkMatrix perspective;
perspective.setIdentity();
perspective.setPerspY(SkIntToScalar(i+1) / 500);
perspective.setSkewX(SkIntToScalar(i+1) / 10);
paint.setShader(gGradMakers[j](pts, gGradData[i], tm, perspective));
canvas->drawRect(r, paint);
canvas->translate(0, SkIntToScalar(120));
}
canvas->restore();
canvas->translate(SkIntToScalar(120), 0);
}
}
bool fDither;
};
DEF_GM( return new GradientsLocalPerspectiveGM(true); )
DEF_GM( return new GradientsLocalPerspectiveGM(false); )
// Based on the original gradient slide, but with perspective applied to
// the view matrix
class GradientsViewPerspectiveGM : public GradientsGM {
public:
GradientsViewPerspectiveGM(bool dither) : INHERITED(dither) { }
private:
SkString getName() const override {
return SkString(fDither ? "gradients_view_perspective" :
"gradients_view_perspective_nodither");
}
SkISize getISize() override { return {840, 500}; }
void onDraw(SkCanvas* canvas) override {
SkMatrix perspective;
perspective.setIdentity();
perspective.setPerspY(0.001f);
perspective.setSkewX(SkIntToScalar(8) / 25);
canvas->concat(perspective);
this->INHERITED::onDraw(canvas);
}
private:
using INHERITED = GradientsGM;
};
DEF_GM( return new GradientsViewPerspectiveGM(true); )
DEF_GM( return new GradientsViewPerspectiveGM(false); )
/*
Inspired by this <canvas> javascript, where we need to detect that we are not
solving a quadratic equation, but must instead solve a linear (since our X^2
coefficient is 0)
ctx.fillStyle = '#f00';
ctx.fillRect(0, 0, 100, 50);
var g = ctx.createRadialGradient(-80, 25, 70, 0, 25, 150);
g.addColorStop(0, '#f00');
g.addColorStop(0.01, '#0f0');
g.addColorStop(0.99, '#0f0');
g.addColorStop(1, '#f00');
ctx.fillStyle = g;
ctx.fillRect(0, 0, 100, 50);
*/
class GradientsDegenrate2PointGM : public skiagm::GM {
public:
GradientsDegenrate2PointGM(bool dither) : fDither(dither) {}
private:
SkString getName() const override {
return SkString(fDither ? "gradients_degenerate_2pt" : "gradients_degenerate_2pt_nodither");
}
SkISize getISize() override { return {320, 320}; }
void onDraw(SkCanvas* canvas) override {
canvas->drawColor(SK_ColorBLUE);
SkColor4f colors[] = { SkColors::kRed, SkColors::kGreen, SkColors::kGreen, SkColors::kRed };
SkScalar pos[] = { 0, 0.01f, 0.99f, SK_Scalar1 };
SkPoint c0;
c0.iset(-80, 25);
SkScalar r0 = SkIntToScalar(70);
SkPoint c1;
c1.iset(0, 25);
SkScalar r1 = SkIntToScalar(150);
SkPaint paint;
paint.setShader(SkShaders::TwoPointConicalGradient(c0, r0, c1, r1,
{{colors, pos, SkTileMode::kClamp}, {}}));
paint.setDither(fDither);
canvas->drawPaint(paint);
}
bool fDither;
};
DEF_GM( return new GradientsDegenrate2PointGM(true); )
DEF_GM( return new GradientsDegenrate2PointGM(false); )
/* skbug.com/40031542
<canvas id="canvas"></canvas>
<script>
var c = document.getElementById("canvas");
var ctx = c.getContext("2d");
ctx.fillStyle = '#ff0';
ctx.fillRect(0, 0, 100, 50);
var g = ctx.createRadialGradient(200, 25, 20, 200, 25, 10);
g.addColorStop(0, '#0f0');
g.addColorStop(0.003, '#f00'); // 0.004 makes this work
g.addColorStop(1, '#ff0');
ctx.fillStyle = g;
ctx.fillRect(0, 0, 100, 50);
</script>
*/
// should draw only green
DEF_SIMPLE_GM(small_color_stop, canvas, 100, 150) {
SkColor4f colors[] = { SkColors::kGreen, SkColors::kRed, SkColors::kYellow };
SkScalar pos[] = { 0, 0.003f, SK_Scalar1 }; // 0.004f makes this work
SkPoint c0 = { 200, 25 };
SkScalar r0 = 20;
SkPoint c1 = { 200, 25 };
SkScalar r1 = 10;
SkPaint paint;
paint.setColor(SK_ColorYELLOW);
canvas->drawRect(SkRect::MakeWH(100, 150), paint);
paint.setShader(SkShaders::TwoPointConicalGradient(c0, r0, c1, r1,
{{colors, pos, SkTileMode::kClamp}, {}}));
canvas->drawRect(SkRect::MakeWH(100, 150), paint);
}
/// Tests correctness of *optimized* codepaths in gradients.
class ClampedGradientsGM : public skiagm::GM {
public:
ClampedGradientsGM(bool dither) : fDither(dither) {}
private:
SkString getName() const override {
return SkString(fDither ? "clamped_gradients" : "clamped_gradients_nodither");
}
SkISize getISize() override { return {640, 510}; }
void onDraw(SkCanvas* canvas) override {
canvas->drawColor(0xFFDDDDDD);
SkRect r = { 0, 0, SkIntToScalar(100), SkIntToScalar(300) };
SkPaint paint;
paint.setDither(fDither);
paint.setAntiAlias(true);
SkPoint center;
center.iset(0, 300);
canvas->translate(SkIntToScalar(20), SkIntToScalar(20));
paint.setShader(SkShaders::RadialGradient(
center, 200, {{gColors, {}, SkTileMode::kClamp}, {}}));
canvas->drawRect(r, paint);
}
bool fDither;
};
DEF_GM( return new ClampedGradientsGM(true); )
DEF_GM( return new ClampedGradientsGM(false); )
/// Checks quality of large radial gradients, which may display
/// some banding.
class RadialGradientGM : public skiagm::GM {
SkString getName() const override { return SkString("radial_gradient"); }
SkISize getISize() override { return {1280, 1280}; }
void onDraw(SkCanvas* canvas) override {
const SkISize dim = this->getISize();
canvas->drawColor(0xFF000000);
SkPaint paint;
paint.setDither(true);
SkPoint center;
center.set(SkIntToScalar(dim.width())/2, SkIntToScalar(dim.height())/2);
SkScalar radius = SkIntToScalar(dim.width())/2;
const SkScalar pos[] = { 0.0f,
0.35f,
1.0f };
SkColorConverter conv({ 0x7f7f7f7f, 0x7f7f7f7f, 0xb2000000 });
paint.setShader(SkShaders::RadialGradient(center, radius,
{{conv.colors4f(), pos, SkTileMode::kClamp}, {}}));
SkRect r = {
0, 0, SkIntToScalar(dim.width()), SkIntToScalar(dim.height())
};
canvas->drawRect(r, paint);
}
};
DEF_GM( return new RadialGradientGM; )
class RadialGradient2GM : public skiagm::GM {
public:
RadialGradient2GM(bool dither) : fDither(dither) {}
private:
SkString getName() const override {
return SkString(fDither ? "radial_gradient2" : "radial_gradient2_nodither");
}
SkISize getISize() override { return {800, 400}; }
// Reproduces the example given in b/7671058.
void onDraw(SkCanvas* canvas) override {
SkPaint paint1, paint2, paint3;
paint1.setStyle(SkPaint::kFill_Style);
paint2.setStyle(SkPaint::kFill_Style);
paint3.setStyle(SkPaint::kFill_Style);
const SkColor4f sweep_colors[] =
{ {1,0,0,1}, {1,1,0,1}, {0,1,0,1}, {0,1,1,1}, {0,0,1,1}, {1,0,1,1}, {1,0,0,1} };
const SkColor4f colors1[] = { {1,1,1,1}, {0,0,0,0} };
const SkColor4f colors2[] = { {0,0,0,1}, {0,0,0,0} };
const SkScalar cx = 200, cy = 200, radius = 150;
SkPoint center;
center.set(cx, cy);
// We can either interpolate endpoints and premultiply each point (default, more precision),
// or premultiply the endpoints first, avoiding the need to premultiply each point (cheap).
static constexpr auto flags = std::to_array<SkGradient::Interpolation::InPremul>({
SkGradient::Interpolation::InPremul::kNo,
SkGradient::Interpolation::InPremul::kYes,
});
const SkTileMode tm = SkTileMode::kClamp;
for (size_t i = 0; i < std::size(flags); i++) {
SkGradient::Interpolation terp{flags[i]};
paint1.setShader(SkShaders::SweepGradient(center, {{sweep_colors, {}, tm}, terp}));
paint2.setShader(SkShaders::RadialGradient(center, radius, {{colors1, {}, tm}, terp}));
paint3.setShader(SkShaders::RadialGradient(center, radius, {{colors2, {}, tm}, terp}));
paint1.setDither(fDither);
paint2.setDither(fDither);
paint3.setDither(fDither);
canvas->drawCircle(cx, cy, radius, paint1);
canvas->drawCircle(cx, cy, radius, paint3);
canvas->drawCircle(cx, cy, radius, paint2);
canvas->translate(400, 0);
}
}
private:
bool fDither;
using INHERITED = GM;
};
DEF_GM( return new RadialGradient2GM(true); )
DEF_GM( return new RadialGradient2GM(false); )
// Shallow radial (shows banding on raster)
class RadialGradient3GM : public skiagm::GM {
public:
RadialGradient3GM(bool dither) : fDither(dither) { }
private:
SkString getName() const override {
return SkString(fDither ? "radial_gradient3" : "radial_gradient3_nodither");
}
SkISize getISize() override { return {500, 500}; }
bool runAsBench() const override { return true; }
void onOnceBeforeDraw() override {
const SkPoint center = { 0, 0 };
const SkScalar kRadius = 3000;
const SkColor4f kColors[] = { {1,1,1,1}, {0,0,0,1} };
fShader = SkShaders::RadialGradient(center, kRadius,
{{kColors, {}, SkTileMode::kClamp}, {}});
}
void onDraw(SkCanvas* canvas) override {
SkPaint paint;
paint.setShader(fShader);
paint.setDither(fDither);
canvas->drawRect(SkRect::MakeWH(500, 500), paint);
}
private:
sk_sp<SkShader> fShader;
bool fDither;
using INHERITED = GM;
};
DEF_GM( return new RadialGradient3GM(true); )
DEF_GM( return new RadialGradient3GM(false); )
class RadialGradient4GM : public skiagm::GM {
public:
RadialGradient4GM(bool dither) : fDither(dither) { }
private:
SkString getName() const override {
return SkString(fDither ? "radial_gradient4" : "radial_gradient4_nodither");
}
SkISize getISize() override { return {500, 500}; }
void onOnceBeforeDraw() override {
const SkPoint center = { 250, 250 };
const SkScalar kRadius = 250;
const SkColor4f colors[] = {
SkColors::kRed, SkColors::kRed, SkColors::kWhite, SkColors::kWhite,SkColors::kRed };
const SkScalar pos[] = { 0, .4f, .4f, .8f, .8f };
fShader = SkShaders::RadialGradient(center, kRadius,
{{colors, pos, SkTileMode::kClamp}, {}});
}
void onDraw(SkCanvas* canvas) override {
SkPaint paint;
paint.setAntiAlias(true);
paint.setDither(fDither);
paint.setShader(fShader);
canvas->drawRect(SkRect::MakeWH(500, 500), paint);
}
private:
sk_sp<SkShader> fShader;
bool fDither;
using INHERITED = GM;
};
DEF_GM( return new RadialGradient4GM(true); )
DEF_GM( return new RadialGradient4GM(false); )
class LinearGradientGM : public skiagm::GM {
public:
LinearGradientGM(bool dither) : fDither(dither) { }
private:
SkString getName() const override {
return SkString(fDither ? "linear_gradient" : "linear_gradient_nodither");
}
const SkScalar kWidthBump = 30.f;
const SkScalar kHeight = 5.f;
const SkScalar kMinWidth = 540.f;
SkISize getISize() override { return {500, 500}; }
void onOnceBeforeDraw() override {
SkPoint pts[2] = { {0, 0}, {0, 0} };
const SkColor4f colors[] = {
SkColors::kWhite, SkColors::kWhite,
SkColor4f::FromColor(0xFF008200), SkColor4f::FromColor(0xFF008200),
SkColors::kWhite, SkColors::kWhite,
};
static constexpr auto unitPos = std::to_array<SkScalar>({0, 50, 70, 500, 540});
std::array<SkScalar, 6> pos;
pos[5] = 1;
for (int index = 0; index < (int) std::size(fShader); ++index) {
pts[1].fX = 500.f + index * kWidthBump;
for (int inner = 0; inner < (int) std::size(unitPos); ++inner) {
pos[inner] = unitPos[inner] / (kMinWidth + index * kWidthBump);
}
fShader[index] = SkShaders::LinearGradient(pts,
{{colors, pos, SkTileMode::kClamp}, {}});
}
}
void onDraw(SkCanvas* canvas) override {
SkPaint paint;
paint.setAntiAlias(true);
paint.setDither(fDither);
for (int index = 0; index < (int) std::size(fShader); ++index) {
paint.setShader(fShader[index]);
canvas->drawRect(SkRect::MakeLTRB(0, index * kHeight, kMinWidth + index * kWidthBump,
(index + 1) * kHeight), paint);
}
}
private:
std::array<sk_sp<SkShader>, 100> fShader;
bool fDither;
using INHERITED = GM;
};
DEF_GM( return new LinearGradientGM(true); )
DEF_GM( return new LinearGradientGM(false); )
class LinearGradientTinyGM : public skiagm::GM {
SkString getName() const override { return SkString("linear_gradient_tiny"); }
SkISize getISize() override { return {600, 500}; }
void onDraw(SkCanvas* canvas) override {
const SkScalar kRectSize = 100;
const unsigned kStopCount = 3;
const SkColor4f colors[kStopCount] = { SkColors::kGreen, SkColors::kRed, SkColors::kGreen };
struct Configs {
SkPoint pts[2];
SkScalar pos[kStopCount];
};
static constexpr auto configs = std::to_array<Configs>({
Configs{ {SkPoint::Make(0, 0), SkPoint::Make(10, 0)}, {0, 0.999999f, 1}},
Configs{ {SkPoint::Make(0, 0), SkPoint::Make(10, 0)}, {0, 0.000001f, 1}},
Configs{ {SkPoint::Make(0, 0), SkPoint::Make(10, 0)}, {0, 0.999999999f, 1}},
Configs{ {SkPoint::Make(0, 0), SkPoint::Make(10, 0)}, {0, 0.000000001f, 1}},
Configs{ {SkPoint::Make(0, 0), SkPoint::Make(0, 10)}, {0, 0.999999f, 1}},
Configs{ {SkPoint::Make(0, 0), SkPoint::Make(0, 10)}, {0, 0.000001f, 1}},
Configs{ {SkPoint::Make(0, 0), SkPoint::Make(0, 10)}, {0, 0.999999999f, 1}},
Configs{ {SkPoint::Make(0, 0), SkPoint::Make(0, 10)}, {0, 0.000000001f, 1}},
Configs{ {SkPoint::Make(0, 0), SkPoint::Make(0.00001f, 0)}, {0, 0.5f, 1}},
Configs{{SkPoint::Make(9.99999f, 0), SkPoint::Make(10, 0)}, {0, 0.5f, 1}},
Configs{ {SkPoint::Make(0, 0), SkPoint::Make(0, 0.00001f)}, {0, 0.5f, 1}},
Configs{{SkPoint::Make(0, 9.99999f), SkPoint::Make(0, 10)}, {0, 0.5f, 1}},
});
SkPaint paint;
for (unsigned i = 0; i < std::size(configs); ++i) {
SkAutoCanvasRestore acr(canvas, true);
paint.setShader(SkShaders::LinearGradient(configs[i].pts,
{{colors, configs[i].pos, SkTileMode::kClamp},
{}}));
canvas->translate(kRectSize * ((i % 4) * 1.5f + 0.25f),
kRectSize * ((i / 4) * 1.5f + 0.25f));
canvas->drawRect(SkRect::MakeWH(kRectSize, kRectSize), paint);
}
}
};
DEF_GM( return new LinearGradientTinyGM; )
} // namespace
///////////////////////////////////////////////////////////////////////////////////////////////////
struct GradRun {
SkColor4f fColors[4];
SkScalar fPos[4];
size_t fCount;
SkGradient grad(SkTileMode tm) const {
return {{{fColors, fCount}, {fPos, fCount}, tm}, {}};
}
};
#define SIZE 121
static sk_sp<SkShader> make_linear(const GradRun& run, SkTileMode mode) {
const SkPoint pts[] { { 30, 30 }, { SIZE - 30, SIZE - 30 } };
return SkShaders::LinearGradient(pts, run.grad(mode));
}
static sk_sp<SkShader> make_radial(const GradRun& run, SkTileMode mode) {
const SkScalar half = SIZE * 0.5f;
return SkShaders::RadialGradient({half,half}, half - 10, run.grad(mode));
}
static sk_sp<SkShader> make_conical(const GradRun& run, SkTileMode mode) {
const SkScalar half = SIZE * 0.5f;
const SkPoint center { half, half };
return SkShaders::TwoPointConicalGradient(center, 20, center, half - 10, run.grad(mode));
}
static sk_sp<SkShader> make_sweep(const GradRun& run, SkTileMode mode) {
const SkScalar half = SIZE * 0.5f;
return SkShaders::SweepGradient({half, half}, run.grad(mode));
}
/*
* Exercise duplicate color-stops, at the ends, and in the middle
*
* At the time of this writing, only Linear correctly deals with duplicates at the ends,
* and then only correctly on CPU backend.
*/
DEF_SIMPLE_GM(gradients_dup_color_stops, canvas, 704, 564) {
const SkColor4f preColor = SkColors::kRed; // clamp color before start
const SkColor4f postColor = SkColors::kBlue; // clamp color after end
const SkColor4f color0 = SkColors::kBlack;
const SkColor4f color1 = SkColors::kGreen;
// should never be seen, fills out fixed-size array
const SkColor4f badColor = SkColor4f::FromColor(0xFF3388BB);
const GradRun runs[] = {
{ { color0, color1, badColor, badColor },
{ 0, 1, -1, -1 },
2,
},
{ { preColor, color0, color1, badColor },
{ 0, 0, 1, -1 },
3,
},
{ { color0, color1, postColor, badColor },
{ 0, 1, 1, -1 },
3,
},
{ { preColor, color0, color1, postColor },
{ 0, 0, 1, 1 },
4,
},
{ { color0, color0, color1, color1 },
{ 0, 0.5f, 0.5f, 1 },
4,
},
};
sk_sp<SkShader> (*factories[])(const GradRun&, SkTileMode) {
make_linear, make_radial, make_conical, make_sweep
};
const SkRect rect = SkRect::MakeWH(SIZE, SIZE);
const SkScalar dx = SIZE + 20;
const SkScalar dy = SIZE + 20;
const SkTileMode mode = SkTileMode::kClamp;
SkPaint paint;
canvas->translate(10, 10 - dy);
for (auto factory : factories) {
canvas->translate(0, dy);
SkAutoCanvasRestore acr(canvas, true);
for (const auto& run : runs) {
paint.setShader(factory(run, mode));
canvas->drawRect(rect, paint);
canvas->translate(dx, 0);
}
}
}
static void draw_many_stops(SkCanvas* canvas) {
const unsigned kStopCount = 200;
const SkPoint pts[] = { {50, 50}, {450, 450}};
std::array<SkColor4f, kStopCount> colors;
for (unsigned i = 0; i < kStopCount; i++) {
switch (i % 5) {
case 0: colors[i] = SkColors::kRed; break;
case 1: colors[i] = SkColors::kGreen; break;
case 2: colors[i] = SkColors::kGreen; break;
case 3: colors[i] = SkColors::kBlue; break;
case 4: colors[i] = SkColors::kRed; break;
}
}
SkPaint p;
p.setShader(SkShaders::LinearGradient(pts, {{colors, {}, SkTileMode::kClamp}, {}}));
canvas->drawRect(SkRect::MakeXYWH(0, 0, 500, 500), p);
}
DEF_SIMPLE_GM(gradient_many_stops, canvas, 500, 500) {
draw_many_stops(canvas);
}
static void draw_many_hard_stops(SkCanvas* canvas) {
const unsigned kStopCount = 300;
const SkPoint pts[] = {{50, 50}, {450, 450}};
std::array<SkColor4f, kStopCount> colors;
std::array<SkScalar, kStopCount> pos;
for (unsigned i = 0; i < kStopCount; i++) {
switch (i % 6) {
case 0: colors[i] = SkColors::kRed; break;
case 1: colors[i] = SkColors::kGreen; break;
case 2: colors[i] = SkColors::kGreen; break;
case 3: colors[i] = SkColors::kBlue; break;
case 4: colors[i] = SkColors::kBlue; break;
case 5: colors[i] = SkColors::kRed; break;
}
pos[i] = (2.0f * (i / 2)) / kStopCount;
}
SkPaint p;
p.setShader(SkShaders::LinearGradient(pts, {{colors, pos, SkTileMode::kClamp}, {}}));
canvas->drawRect(SkRect::MakeXYWH(0, 0, 500, 500), p);
}
DEF_SIMPLE_GM(gradient_many_hard_stops, canvas, 500, 500) {
draw_many_hard_stops(canvas);
}
static void draw_circle_shader(SkCanvas* canvas, SkScalar cx, SkScalar cy, SkScalar r,
sk_sp<SkShader> (*shaderFunc)()) {
SkPaint p;
p.setAntiAlias(true);
p.setShader(shaderFunc());
canvas->drawCircle(cx, cy, r, p);
p.setShader(nullptr);
p.setColor(SK_ColorGRAY);
p.setStyle(SkPaint::kStroke_Style);
p.setStrokeWidth(2);
canvas->drawCircle(cx, cy, r, p);
}
DEF_SIMPLE_GM(fancy_gradients, canvas, 800, 300) {
draw_circle_shader(canvas, 150, 150, 100, []() -> sk_sp<SkShader> {
// Checkerboard using two linear gradients + picture shader.
SkScalar kTileSize = 80 / sqrtf(2);
SkColor4f colors1[] = { {0,0,0,1}, {0,0,0,1},
{1,1,1,1}, {1,1,1,1},
{0,0,0,1}, {0,0,0,1} };
SkColor4f colors2[] = { {0,0,0,1}, {0,0,0,1},
{0,0,0,0}, {0,0,0,0},
{0,0,0,1}, {0,0,0,1} };
SkScalar pos[] = { 0, .25f, .25f, .75f, .75f, 1 };
static_assert(std::size(colors1) == std::size(pos), "color/pos size mismatch");
static_assert(std::size(colors2) == std::size(pos), "color/pos size mismatch");
SkPictureRecorder recorder;
recorder.beginRecording(SkRect::MakeWH(kTileSize, kTileSize));
SkPaint p;
SkPoint pts1[] = { { 0, 0 }, { kTileSize, kTileSize }};
p.setShader(SkShaders::LinearGradient(pts1, {{colors1, pos, SkTileMode::kClamp}, {}}));
recorder.getRecordingCanvas()->drawPaint(p);
SkPoint pts2[] = { { 0, kTileSize }, { kTileSize, 0 }};
p.setShader(SkShaders::LinearGradient(pts2, {{colors2, pos, SkTileMode::kClamp}, {}}));
recorder.getRecordingCanvas()->drawPaint(p);
SkMatrix m = SkMatrix::I();
m.preRotate(45);
return recorder.finishRecordingAsPicture()->makeShader(
SkTileMode::kRepeat, SkTileMode::kRepeat,
SkFilterMode::kNearest, &m, nullptr);
});
draw_circle_shader(canvas, 400, 150, 100, []() -> sk_sp<SkShader> {
// Checkerboard using a sweep gradient + picture shader.
SkScalar kTileSize = 80;
SkColor4f colors[] = { {0,0,0,1}, {0,0,0,1},
{1,1,1,1}, {1,1,1,1},
{0,0,0,1}, {0,0,0,1},
{1,1,1,1}, {1,1,1,1} };
SkScalar pos[] = { 0, .25f, .25f, .5f, .5f, .75f, .75f, 1 };
static_assert(std::size(colors) == std::size(pos), "color/pos size mismatch");
SkPaint p;
p.setShader(SkShaders::SweepGradient({kTileSize / 2, kTileSize / 2},
{{colors, pos, SkTileMode::kClamp}, {}}));
SkPictureRecorder recorder;
recorder.beginRecording(SkRect::MakeWH(kTileSize, kTileSize))->drawPaint(p);
return recorder.finishRecordingAsPicture()->makeShader(
SkTileMode::kRepeat,
SkTileMode::kRepeat, SkFilterMode::kNearest);
});
draw_circle_shader(canvas, 650, 150, 100, []() -> sk_sp<SkShader> {
// Dartboard using sweep + radial.
const SkColor4f a = {1,1,1,1};
const SkColor4f b = {0,0,0,1};
SkColor4f colors[] = { a, a, b, b, a, a, b, b, a, a, b, b, a, a, b, b};
SkScalar pos[] = { 0, .125f, .125f, .25f, .25f, .375f, .375f, .5f, .5f,
.625f, .625f, .75f, .75f, .875f, .875f, 1};
static_assert(std::size(colors) == std::size(pos), "color/pos size mismatch");
SkPoint center = { 650, 150 };
sk_sp<SkShader> sweep1 = SkShaders::SweepGradient(center,
{{colors, pos, SkTileMode::kClamp}, {}});
SkMatrix m = SkMatrix::I();
m.preRotate(22.5f, center.x(), center.y());
sk_sp<SkShader> sweep2 = SkShaders::SweepGradient(center,
{{colors, pos, SkTileMode::kClamp}, {}}, &m);
sk_sp<SkShader> sweep(SkShaders::Blend(SkBlendMode::kExclusion, sweep1, sweep2));
SkScalar radialPos[] = { 0, .02f, .02f, .04f, .04f, .08f, .08f, .16f, .16f, .31f, .31f,
.62f, .62f, 1, 1, 1 };
static_assert(std::size(colors) == std::size(radialPos),
"color/pos size mismatch");
return SkShaders::Blend(SkBlendMode::kExclusion, sweep,
SkShaders::RadialGradient(center, 100,
{{colors, radialPos, SkTileMode::kClamp}, {}}));
});
}
DEF_SIMPLE_GM(sweep_tiling, canvas, 690, 512) {
static constexpr SkScalar size = 160;
static constexpr SkColor4f colors[] = { SkColors::kBlue, SkColors::kYellow, SkColors::kGreen };
static constexpr SkScalar pos[] = { 0, .25f, .50f };
static_assert(std::size(colors) == std::size(pos), "size mismatch");
static constexpr SkTileMode modes[] = { SkTileMode::kClamp,
SkTileMode::kRepeat,
SkTileMode::kMirror };
static const struct {
SkScalar start, end;
} angles[] = {
{ -330, -270 },
{ 30, 90 },
{ 390, 450 },
{ -30, 800 },
};
SkPaint p;
const SkRect r = SkRect::MakeWH(size, size);
for (auto mode : modes) {
{
SkAutoCanvasRestore acr(canvas, true);
for (auto angle : angles) {
p.setShader(SkShaders::SweepGradient({size / 2, size / 2}, angle.start, angle.end,
{{colors, pos, mode}, {}}));
canvas->drawRect(r, p);
canvas->translate(size * 1.1f, 0);
}
}
canvas->translate(0, size * 1.1f);
}
}
DEF_SIMPLE_GM(rgbw_sweep_gradient, canvas, 100, 100) {
static constexpr SkScalar size = 100;
static constexpr SkColor4f colors[] = {SkColors::kWhite, SkColors::kWhite,
SkColors::kBlue, SkColors::kBlue,
SkColors::kRed, SkColors::kRed,
SkColors::kGreen, SkColors::kGreen};
static constexpr SkScalar pos[] = { 0, .25f, .25f, .50f, .50f, .75, .75, 1 };
static_assert(std::size(colors) == std::size(pos), "size mismatch");
SkPaint p;
p.setShader(SkShaders::SweepGradient({size / 2, size / 2},
{{colors, pos, SkTileMode::kClamp}, {}}));
canvas->drawRect(SkRect::MakeWH(size, size), p);
}
// Exercises the special-case Ganesh gradient effects.
DEF_SIMPLE_GM(gradients_interesting, canvas, 640, 1300) {
static const SkColor4f colors2[] = { SkColors::kRed, SkColors::kBlue };
static const SkColor4f colors3[] = { SkColors::kRed, SkColors::kYellow, SkColors::kBlue };
static const SkColor4f colors4[] = {
SkColors::kRed, SkColors::kYellow, SkColors::kYellow, SkColors::kBlue };
static const SkScalar softRight[] = { 0, .999f, 1 }; // Based on Android launcher "clipping"
static const SkScalar hardLeft[] = { 0, 0, 1 };
static const SkScalar hardRight[] = { 0, 1, 1 };
static const SkScalar hardCenter[] = { 0, .5f, .5f, 1 };
static const struct {
SkSpan<const SkColor4f> colors;
SkSpan<const float> pos;
} configs[] = {
{ colors2, {} }, // kTwo_ColorType
{ colors3, {} }, // kThree_ColorType (simple)
{ colors3, softRight }, // kThree_ColorType (tricky)
{ colors3, hardLeft }, // kHardStopLeftEdged_ColorType
{ colors3, hardRight }, // kHardStopRightEdged_ColorType
{ colors4, hardCenter }, // kSingleHardStop_ColorType
};
static const SkTileMode modes[] = {
SkTileMode::kClamp,
SkTileMode::kRepeat,
SkTileMode::kMirror,
};
static constexpr SkScalar size = 200;
static const SkPoint pts[] = { { size / 3, size / 3 }, { size * 2 / 3, size * 2 / 3} };
SkPaint p;
for (const auto& cfg : configs) {
{
SkAutoCanvasRestore acr(canvas, true);
for (auto mode : modes) {
SkGradient grad = {{cfg.colors, cfg.pos, mode}, {}};
p.setShader(SkShaders::LinearGradient(pts, grad));
canvas->drawRect(SkRect::MakeWH(size, size), p);
canvas->translate(size * 1.1f, 0);
}
}
canvas->translate(0, size * 1.1f);
}
}
// TODO(skbug.com/40044214): Still need to test degenerate gradients in strange color spaces
DEF_SIMPLE_GM_BG(gradients_color_space, canvas, 265, 355, SK_ColorGRAY) {
using CS = SkGradient::Interpolation::ColorSpace;
struct Config {
CS fColorSpace;
const char* fLabel;
};
static const Config kConfigs[] = {
{CS::kSRGB, "sRGB"},
{CS::kSRGBLinear, "Linear"},
{CS::kLab, "Lab"},
{CS::kOKLab, "OKLab"},
{CS::kOKLabGamutMap, "OKLabGamutMap"},
{CS::kLCH, "LCH"},
{CS::kOKLCH, "OKLCH"},
{CS::kOKLCHGamutMap, "OKLCHGamutMap"},
{CS::kHSL, "HSL"},
{CS::kHWB, "HWB"},
{CS::kA98RGB, "a98RGB"},
{CS::kProphotoRGB, "ProPhotoRGB"},
{CS::kDisplayP3, "DisplayP3"},
{CS::kRec2020, "Rec2020"},
};
SkPoint pts[] = {{0, 0}, {200, 0}};
SkColor4f colors[] = {SkColors::kBlue, SkColors::kYellow};
SkPaint labelPaint;
SkPaint p;
SkGradient::Interpolation interpolation;
canvas->translate(5, 5);
SkFont font = ToolUtils::DefaultPortableFont();
for (const Config& config : kConfigs) {
interpolation.fColorSpace = config.fColorSpace;
SkGradient g = {{colors, {}, SkTileMode::kClamp, SkColorSpace::MakeSRGB()}, interpolation};
p.setShader(SkShaders::LinearGradient(pts, g));
canvas->drawRect({0, 0, 200, 20}, p);
canvas->drawSimpleText(config.fLabel, strlen(config.fLabel), SkTextEncoding::kUTF8, 210, 15,
font, labelPaint);
canvas->translate(0, 25);
}
}
DEF_SIMPLE_GM_BG(gradients_hue_method, canvas, 285, 155, SK_ColorGRAY) {
using HM = SkGradient::Interpolation::HueMethod;
struct Config {
HM fHueMethod;
const char* fLabel;
};
static const Config kConfigs[] = {
{ HM::kShorter, "Shorter" },
{ HM::kLonger, "Longer" },
{ HM::kIncreasing, "Increasing" },
{ HM::kDecreasing, "Decreasing" },
};
SkPoint pts[] = {{0, 0}, {200, 0}};
SkColor4f colors[] = {SkColors::kRed, SkColors::kGreen, SkColors::kRed, SkColors::kRed };
SkPaint labelPaint;
SkPaint p;
SkGradient::Interpolation interpolation;
interpolation.fColorSpace = SkGradient::Interpolation::ColorSpace::kHSL;
canvas->translate(5, 5);
SkFont font = ToolUtils::DefaultPortableFont();
for (const Config& config : kConfigs) {
interpolation.fHueMethod = config.fHueMethod;
SkGradient g = {{colors, {}, SkTileMode::kClamp, SkColorSpace::MakeSRGB()}, interpolation};
p.setShader(SkShaders::LinearGradient(pts, g));
canvas->drawRect({0, 0, 200, 20}, p);
canvas->drawSimpleText(config.fLabel, strlen(config.fLabel), SkTextEncoding::kUTF8, 210, 15,
font, labelPaint);
canvas->translate(0, 25);
}
// Test a bug (skbug.com/40044215) with how gradient shaders handle explicit positions.
// If there are no explicit positions at 0 or 1, those are automatically added, with copies of
// the first/last color. When using kLonger, this can produce extra gradient that should
// actually be solid. This gradient *should* be:
// |- solid red -|- red to green, the long way -|- solid green -|
interpolation.fHueMethod = HM::kLonger;
SkScalar middlePos[] = { 0.3f, 0.7f };
SkGradient g = {{{colors, 2}, middlePos, SkTileMode::kClamp, SkColorSpace::MakeSRGB()},
interpolation};
p.setShader(SkShaders::LinearGradient(pts, g));
canvas->drawRect({0, 0, 200, 20}, p);
canvas->translate(0, 25);
// However... if the user explicitly includes those duplicate color stops in kLonger mode,
// we expect the gradient to do a full rotation in those regions:
// |- full circle, red to red -|- red to green -|- full circle, green to green -|
colors[0] = colors[1] = SkColors::kRed;
colors[2] = colors[3] = SkColors::kGreen;
SkScalar allPos[] = { 0.0f, 0.3f, 0.7f, 1.0f };
g = {{colors, allPos, SkTileMode::kClamp, SkColorSpace::MakeSRGB()}, interpolation};
p.setShader(SkShaders::LinearGradient(pts, g));
canvas->drawRect({0, 0, 200, 20}, p);
canvas->translate(0, 25);
}
DEF_SIMPLE_GM_BG(gradients_color_space_tilemode, canvas, 360, 105, SK_ColorGRAY) {
// Test exotic (CSS) gradient color spaces in conjunction with tile modes. Rather than test
// every combination, we pick one color space that has a sufficiently strange interpolated
// representation (OKLCH) and just use that. We're mostly interested in making sure that things
// like decal mode are implemented at the correct time in the pipeline, relative to hue
// conversion, re-premultiplication, etc.
SkPoint pts[] = {{20, 0}, {120, 0}};
SkColor4f colors[] = {SkColors::kBlue, SkColors::kYellow};
SkPaint p;
SkGradient::Interpolation interpolation;
interpolation.fColorSpace = SkGradient::Interpolation::ColorSpace::kOKLCH;
canvas->translate(5, 5);
for (int tm = 0; tm < kSkTileModeCount; ++tm) {
SkGradient g = {{colors, {}, static_cast<SkTileMode>(tm)}, interpolation};
p.setShader(SkShaders::LinearGradient(pts, g));
canvas->drawRect({0, 0, 350, 20}, p);
canvas->translate(0, 25);
}
}
DEF_SIMPLE_GM_BG(gradients_color_space_many_stops, canvas, 500, 500, SK_ColorGRAY) {
// Test exotic (CSS) gradient color spaces with many stops. Rather than test every combination,
// we pick one color space that has a sufficiently strange interpolated representation (OKLCH)
// and just use that. We're mostly interested in making sure that the texture fallback on GPU
// works correctly.
const SkPoint pts[] = { {50, 50}, {450, 465}};
const unsigned kStopCount = 200;
std::array<SkColor4f, kStopCount> colors;
for (unsigned i = 0; i < kStopCount; i++) {
switch (i % 5) {
case 0: colors[i] = SkColors::kRed; break;
case 1: colors[i] = SkColors::kGreen; break;
case 2: colors[i] = SkColors::kGreen; break;
case 3: colors[i] = SkColors::kBlue; break;
case 4: colors[i] = SkColors::kRed; break;
}
}
SkPaint p;
SkGradient::Interpolation interpolation;
interpolation.fColorSpace = SkGradient::Interpolation::ColorSpace::kOKLCH;
p.setShader(SkShaders::LinearGradient(pts,
{{colors, {}, SkTileMode::kClamp, SkColorSpace::MakeSRGB()}, interpolation}));
canvas->drawRect(SkRect::MakeXYWH(0, 0, 500, 500), p);
}
DEF_SIMPLE_GM(gradients_alpha_many_stops, canvas, 100, 100) {
static const SkPoint kPts[] = {{0.f, 0.f}, {0.f, 100.f}};
// From https://issues.chromium.org/issues/401546700, this encounters Graphite's
// storage buffer option for storing gradient buffers AND uses colors that emphasize
// premul vs. unpremul handling of the color data.
static const float kPos[] = {0.f, 0.19f, 0.34f, 0.47f, 0.565f, 0.65f,
0.73f, 0.802f, 0.861f, 0.91f, 0.952f, 0.982f, 1.f};
static constexpr float kG = 34 / 255.f;
static const SkColor4f kColors[] = {{kG, kG, kG, 1.f},
{kG, kG, kG, 0.738f},
{kG, kG, kG, 0.541f},
{kG, kG, kG, 0.382f},
{kG, kG, kG, 0.278f},
{kG, kG, kG, 0.194f},
{kG, kG, kG, 0.126f},
{kG, kG, kG, 0.075f},
{kG, kG, kG, 0.042f},
{kG, kG, kG, 0.021f},
{kG, kG, kG, 0.008f},
{kG, kG, kG, 0.002f},
{kG, kG, kG, 0.f}};
canvas->clear(SkColor4f{0.5f, 0.5f, 0.5f, 1.f});
SkPaint paint;
paint.setShader(SkShaders::LinearGradient(kPts, {{kColors, kPos, SkTileMode::kClamp}, {}}));
canvas->drawPaint(paint);
}
static void draw_powerless_hue_gradients(SkCanvas* canvas,
SkGradient::Interpolation::ColorSpace colorSpace) {
ToolUtils::draw_checkerboard(canvas);
auto nextRow = [=]() {
canvas->restore();
canvas->translate(0, 25);
canvas->save();
};
auto gradient = [&](std::initializer_list<SkColor4f> colors,
std::initializer_list<float> pos,
bool inPremul = false) {
using Interpolation = SkGradient::Interpolation;
SkASSERT(pos.size() == 0 || pos.size() == colors.size());
SkPaint paint;
SkPoint pts[] = {{0, 0}, {200, 0}};
Interpolation interpolation;
interpolation.fColorSpace = colorSpace;
interpolation.fInPremul = static_cast<Interpolation::InPremul>(inPremul);
paint.setShader(SkShaders::LinearGradient(pts, {{colors, pos, SkTileMode::kClamp},
interpolation}));
canvas->drawRect({0, 0, 200, 20}, paint);
canvas->translate(205, 0); // next column
};
canvas->translate(5, 5);
canvas->save();
// For each test case, the first gradient (first column) has an under-specified result due to a
// powerless component after conversion to LCH. The second gradient (second column) "hints" the
// correct result, by slightly tinting the otherwise powerless color.
gradient({SkColors::kWhite, SkColors::kBlue}, {});
gradient({{0.99f, 0.99f, 1.00f, 1.0f}, SkColors::kBlue}, {}); // white, with blue hue
nextRow();
gradient({SkColors::kBlack, SkColors::kBlue}, {});
gradient({{0.00f, 0.00f, 0.01f, 1.0f}, SkColors::kBlue}, {}); // black, with blue hue
nextRow();
// Transparent cases are done in both premul and unpremul interpolation:
gradient({SkColors::kTransparent, SkColors::kBlue}, {}, /*inPremul=*/false);
gradient({{0.00f, 0.00f, 0.01f, 0.0f}, SkColors::kBlue}, {}, /*inPremul=*/false);
nextRow();
gradient({SkColors::kTransparent, SkColors::kBlue}, {}, /*inPremul=*/true);
gradient({{0.00f, 0.00f, 0.01f, 0.0f}, SkColors::kBlue}, {}, /*inPremul=*/true);
nextRow();
gradient({{1.00f, 1.00f, 1.00f, 0.0f}, SkColors::kBlue}, {}, /*inPremul=*/false);
gradient({{0.99f, 0.99f, 1.00f, 0.0f}, SkColors::kBlue}, {}, /*inPremul=*/false);
nextRow();
gradient({{1.00f, 1.00f, 1.00f, 0.0f}, SkColors::kBlue}, {}, /*inPremul=*/true);
gradient({{0.99f, 0.99f, 1.00f, 0.0f}, SkColors::kBlue}, {}, /*inPremul=*/true);
nextRow();
// Now we test three-stop gradients, where the middle stop needs to be "split" to handle the
// different hues on either side. Again, the second column explicitly injects those to produce
// a reference result. See: https://github.com/w3c/csswg-drafts/issues/9295
gradient({SkColors::kRed, SkColors::kWhite, SkColors::kBlue}, {});
gradient({SkColors::kRed,
{1.00f, 0.99f, 0.99f, 1.0f},
{0.99f, 0.99f, 1.00f, 1.0f},
SkColors::kBlue},
{0.0f, 0.5f, 0.5f, 1.0f});
nextRow();
gradient({SkColors::kRed, SkColors::kBlack, SkColors::kBlue}, {});
gradient({SkColors::kRed,
{0.01f, 0.00f, 0.00f, 1.0f},
{0.00f, 0.00f, 0.01f, 1.0f},
SkColors::kBlue},
{0.0f, 0.5f, 0.5f, 1.0f});
nextRow();
gradient({SkColors::kRed, SkColors::kTransparent, SkColors::kBlue}, {});
gradient({SkColors::kRed,
{0.01f, 0.00f, 0.00f, 0.0f},
{0.00f, 0.00f, 0.01f, 0.0f},
SkColors::kBlue},
{0.0f, 0.5f, 0.5f, 1.0f});
nextRow();
// Now do a few black-white tests, to ensure that the hue propagation works correctly, even
// when there isn't any hue in the adjacent stops.
using HueMethod = SkGradient::Interpolation::HueMethod;
auto blackWhiteGradient = [&](HueMethod hm) {
using Interpolation = SkGradient::Interpolation;
SkPaint paint;
SkPoint pts[] = {{0, 0}, {405, 0}};
Interpolation interpolation;
interpolation.fColorSpace = colorSpace;
interpolation.fHueMethod = hm;
const SkColor4f colors[] = {SkColors::kWhite, SkColors::kGray,
SkColors::kWhite, SkColors::kDkGray,
SkColors::kWhite, SkColors::kBlack};
paint.setShader(SkShaders::LinearGradient(pts, {{colors, {}, SkTileMode::kClamp},
interpolation}));
canvas->drawRect({0, 0, 405, 20}, paint);
nextRow();
};
blackWhiteGradient(HueMethod::kShorter);
blackWhiteGradient(HueMethod::kIncreasing);
blackWhiteGradient(HueMethod::kDecreasing);
blackWhiteGradient(HueMethod::kLonger);
}
#define DEF_POWERLESS_HUE_GM(colorSpace) \
DEF_SIMPLE_GM(gradients_powerless_hue_##colorSpace, canvas, 415, 330) { \
draw_powerless_hue_gradients(canvas, \
SkGradient::Interpolation::ColorSpace::k##colorSpace); \
}
DEF_POWERLESS_HUE_GM(LCH)
DEF_POWERLESS_HUE_GM(OKLCH)
DEF_POWERLESS_HUE_GM(HSL)
DEF_POWERLESS_HUE_GM(HWB)