gm/perspshaders.cpp

   1 /*
   2  * Copyright 2015 Google Inc.
   3  *
   4  * Use of this source code is governed by a BSD-style license that can be
   5  * found in the LICENSE file.
   6  */
   7
   8 #include "gm.h"
   9 #include "sk_tool_utils.h"
  10 #include "SkGradientShader.h"
  11 #include "SkImage.h"
  12 #include "SkPath.h"
  13 #include "SkSurface.h"
  14
  15 static sk_sp<SkImage> make_image(SkCanvas* origCanvas, int w, int h) {
  16     SkImageInfo info = SkImageInfo::MakeN32Premul(w, h);
  17     auto surface(origCanvas->makeSurface(info));
  18     if (nullptr == surface) {
  19         surface = SkSurface::MakeRaster(info);
  20     }
  21     SkCanvas* canvas = surface->getCanvas();
  22
  23     sk_tool_utils::draw_checkerboard(canvas, SK_ColorRED, SK_ColorGREEN, w/10);
  24     return surface->makeImageSnapshot();
  25 }
  26
  27 namespace skiagm {
  28
  29 class PerspShadersGM : public GM {
  30 public:
  31     PerspShadersGM(bool doAA) : fDoAA(doAA) { }
  32
  33 protected:
  34     SkString onShortName() override {
  35         SkString name;
  36         name.printf("persp_shaders_%s",
  37                      fDoAA ? "aa" : "bw");
  38         return name;
  39     }
  40
  41     SkISize onISize() override {
  42         return SkISize::Make(kCellSize*kNumCols, kCellSize*kNumRows);
  43     }
  44
  45     void onOnceBeforeDraw() override {
  46         fBitmap = sk_tool_utils::create_checkerboard_bitmap(kCellSize, kCellSize,
  47                                                             SK_ColorBLUE, SK_ColorYELLOW,
  48                                                             kCellSize/10);
  49
  50         fBitmapShader = SkShader::MakeBitmapShader(fBitmap, SkShader::kClamp_TileMode,
  51                                                    SkShader::kClamp_TileMode);
  52         SkPoint pts1[] = {
  53             { 0, 0 },
  54             { SkIntToScalar(kCellSize), SkIntToScalar(kCellSize) }
  55         };
  56         SkPoint pts2[] = {
  57             { 0, 0 },
  58             { 0, SkIntToScalar(kCellSize) }
  59         };
  60         constexpr SkColor colors[] = {
  61             SK_ColorRED, SK_ColorGREEN, SK_ColorRED, SK_ColorGREEN, SK_ColorRED
  62         };
  63         constexpr SkScalar pos[] = { 0, 0.25f, 0.5f, 0.75f, SK_Scalar1 };
  64
  65         fLinearGrad1 = SkGradientShader::MakeLinear(pts1, colors, pos, SK_ARRAY_COUNT(colors),
  66                                                     SkShader::kClamp_TileMode);
  67         fLinearGrad2 = SkGradientShader::MakeLinear(pts2, colors, pos, SK_ARRAY_COUNT(colors),
  68                                                     SkShader::kClamp_TileMode);
  69
  70         fPerspMatrix.reset();
  71         fPerspMatrix.setPerspY(SK_Scalar1 / 50);
  72
  73         fPath.moveTo(0, 0);
  74         fPath.lineTo(0, SkIntToScalar(kCellSize));
  75         fPath.lineTo(kCellSize/2.0f, kCellSize/2.0f);
  76         fPath.lineTo(SkIntToScalar(kCellSize), SkIntToScalar(kCellSize));
  77         fPath.lineTo(SkIntToScalar(kCellSize), 0);
  78         fPath.close();
  79     }
  80
  81     void drawRow(SkCanvas* canvas, SkFilterQuality filterQ) {
  82         SkPaint filterPaint;
  83         filterPaint.setFilterQuality(filterQ);
  84         filterPaint.setAntiAlias(fDoAA);
  85
  86         SkPaint pathPaint;
  87         pathPaint.setShader(fBitmapShader);
  88         pathPaint.setFilterQuality(filterQ);
  89         pathPaint.setAntiAlias(fDoAA);
  90
  91         SkPaint gradPaint1;
  92         gradPaint1.setShader(fLinearGrad1);
  93         gradPaint1.setAntiAlias(fDoAA);
  94         SkPaint gradPaint2;
  95         gradPaint2.setShader(fLinearGrad2);
  96         gradPaint2.setAntiAlias(fDoAA);
  97
  98         SkRect r = SkRect::MakeWH(SkIntToScalar(kCellSize), SkIntToScalar(kCellSize));
  99
 100         canvas->save();
 101
 102         canvas->save();
 103         canvas->concat(fPerspMatrix);
 104         canvas->drawBitmapRect(fBitmap, r, &filterPaint);
 105         canvas->restore();
 106
 107         canvas->translate(SkIntToScalar(kCellSize), 0);
 108         canvas->save();
 109         canvas->concat(fPerspMatrix);
 110         canvas->drawImage(fImage.get(), 0, 0, &filterPaint);
 111         canvas->restore();
 112
 113         canvas->translate(SkIntToScalar(kCellSize), 0);
 114         canvas->save();
 115         canvas->concat(fPerspMatrix);
 116         canvas->drawRect(r, pathPaint);
 117         canvas->restore();
 118
 119         canvas->translate(SkIntToScalar(kCellSize), 0);
 120         canvas->save();
 121         canvas->concat(fPerspMatrix);
 122         canvas->drawPath(fPath, pathPaint);
 123         canvas->restore();
 124
 125         canvas->translate(SkIntToScalar(kCellSize), 0);
 126         canvas->save();
 127         canvas->concat(fPerspMatrix);
 128         canvas->drawRect(r, gradPaint1);
 129         canvas->restore();
 130
 131         canvas->translate(SkIntToScalar(kCellSize), 0);
 132         canvas->save();
 133         canvas->concat(fPerspMatrix);
 134         canvas->drawPath(fPath, gradPaint2);
 135         canvas->restore();
 136
 137         canvas->restore();
 138     }
 139
 140     void onDraw(SkCanvas* canvas) override {
 141         if (!fImage) {
 142             fImage = make_image(canvas, kCellSize, kCellSize);
 143         }
 144
 145         this->drawRow(canvas, kNone_SkFilterQuality);
 146         canvas->translate(0, SkIntToScalar(kCellSize));
 147         this->drawRow(canvas, kLow_SkFilterQuality);
 148         canvas->translate(0, SkIntToScalar(kCellSize));
 149         this->drawRow(canvas, kMedium_SkFilterQuality);
 150         canvas->translate(0, SkIntToScalar(kCellSize));
 151         this->drawRow(canvas, kHigh_SkFilterQuality);
 152         canvas->translate(0, SkIntToScalar(kCellSize));
 153     }
 154 private:
 155     static constexpr int kCellSize = 50;
 156     static constexpr int kNumRows = 4;
 157     static constexpr int kNumCols = 6;
 158
 159     bool            fDoAA;
 160     SkPath          fPath;
 161     sk_sp<SkShader> fBitmapShader;
 162     sk_sp<SkShader> fLinearGrad1;
 163     sk_sp<SkShader> fLinearGrad2;
 164     SkMatrix        fPerspMatrix;
 165     sk_sp<SkImage>  fImage;
 166     SkBitmap        fBitmap;
 167
 168     typedef GM INHERITED;
 169 };
 170
 171 //////////////////////////////////////////////////////////////////////////////
 172
 173 DEF_GM(return new PerspShadersGM(true);)
 174 DEF_GM(return new PerspShadersGM(false);)
 175 }