148 lines
5.3 KiB
C++
148 lines
5.3 KiB
C++
/*
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* Copyright 2021 Google LLC
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*
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* Use of this source code is governed by a BSD-style license that can be
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* found in the LICENSE file.
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*/
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/*
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* This GM creates the same gradients as the Chromium test fillrect_gradient:
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* http://osscs/chromium/chromium/src/+/main:third_party/blink/web_tests/fast/canvas/fillrect_gradient.html
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*/
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#include "gm/gm.h"
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#include "include/core/SkCanvas.h"
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#include "include/core/SkColor.h"
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#include "include/core/SkPaint.h"
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#include "include/core/SkPoint.h"
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#include "include/core/SkRect.h"
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#include "include/core/SkRefCnt.h"
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#include "include/core/SkScalar.h"
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#include "include/core/SkShader.h"
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#include "include/core/SkSize.h"
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#include "include/core/SkString.h"
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#include "include/core/SkTileMode.h"
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#include "include/effects/SkGradientShader.h"
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const int kCellSize = 50;
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const int kNumColumns = 2;
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const int kNumRows = 9;
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const int kPadSize = 10;
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class FillrectGradientGM : public skiagm::GM {
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public:
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FillrectGradientGM() {}
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protected:
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struct GradientStop {
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float pos;
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SkColor color;
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};
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SkString onShortName() override {
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return SkString("fillrect_gradient");
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}
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SkISize onISize() override {
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return SkISize::Make(kNumColumns * (kCellSize + kPadSize),
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kNumRows * (kCellSize + kPadSize));
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}
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void drawGradient(SkCanvas* canvas, std::initializer_list<GradientStop> stops) {
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std::vector<SkColor> colors;
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std::vector<SkScalar> positions;
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colors.reserve(stops.size());
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positions.reserve(stops.size());
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for (const GradientStop& stop : stops) {
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colors.push_back(stop.color);
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positions.push_back(stop.pos);
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}
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static constexpr SkPoint points[] = {
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SkPoint::Make(kCellSize, 0),
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SkPoint::Make(kCellSize, kCellSize),
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};
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// Draw the gradient linearly.
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sk_sp<SkShader> shader = SkGradientShader::MakeLinear(points,
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colors.data(),
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positions.data(),
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colors.size(),
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SkTileMode::kClamp);
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SkPaint paint;
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paint.setShader(shader);
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canvas->drawRect(SkRect::MakeXYWH(0, 0, kCellSize, kCellSize), paint);
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canvas->save();
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canvas->translate(kCellSize + kPadSize, 0);
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// Draw the gradient radially.
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shader = SkGradientShader::MakeRadial(SkPoint::Make(kCellSize / 2, kCellSize / 2),
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kCellSize / 2,
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colors.data(),
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positions.data(),
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colors.size(),
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SkTileMode::kClamp);
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paint.setShader(shader);
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canvas->drawRect(SkRect::MakeXYWH(0, 0, kCellSize, kCellSize), paint);
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canvas->restore();
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canvas->translate(0, kCellSize + kPadSize);
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}
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void onDraw(SkCanvas* canvas) override {
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// Simple gradient: Green to white
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this->drawGradient(canvas, {{0.0f, SK_ColorGREEN}, {1.0f, SK_ColorWHITE}});
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// Multiple sections: Green to white to red
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this->drawGradient(canvas,
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{{0.0f, SK_ColorGREEN}, {0.5f, SK_ColorWHITE}, {1.0f, SK_ColorRED}});
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// No stops at 0.0 or 1.0: Larger green to white to larger red
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this->drawGradient(canvas,
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{{0.4f, SK_ColorGREEN}, {0.5f, SK_ColorWHITE}, {0.6f, SK_ColorRED}});
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// Only one stop, at zero: Solid red
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this->drawGradient(canvas, {{0.0f, SK_ColorRED}});
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// Only one stop, at 1.0: Solid red
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this->drawGradient(canvas, {{1.0f, SK_ColorRED}});
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// Only one stop, in the middle: Solid red
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this->drawGradient(canvas, {{0.5f, SK_ColorRED}});
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// Disjoint gradients (multiple stops at the same offset)
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// Blue to white in the top (inner) half, red to yellow in the bottom (outer) half
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this->drawGradient(canvas,
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{{0.0f, SK_ColorBLUE},
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{0.5f, SK_ColorWHITE},
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{0.5f, SK_ColorRED},
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{1.0f, SK_ColorYELLOW}});
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// Ignored stops: Blue to white, red to yellow (same as previous)
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this->drawGradient(canvas,
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{{0.0f, SK_ColorBLUE},
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{0.5f, SK_ColorWHITE},
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{0.5f, SK_ColorGRAY},
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{0.5f, SK_ColorCYAN},
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{0.5f, SK_ColorRED},
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{1.0f, SK_ColorYELLOW}});
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// Unsorted stops: Blue to white, red to yellow
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// Unlike Chrome, we don't sort the stops, so this renders differently than the prior cell.
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this->drawGradient(canvas,
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{{0.5f, SK_ColorWHITE},
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{0.5f, SK_ColorGRAY},
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{1.0f, SK_ColorYELLOW},
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{0.5f, SK_ColorCYAN},
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{0.5f, SK_ColorRED},
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{0.0f, SK_ColorBLUE}});
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}
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private:
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using INHERITED = skiagm::GM;
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};
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DEF_GM(return new FillrectGradientGM;)
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