gm/composeshader.cpp

   1 /*
   2  * Copyright 2012 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
  10 #include "SkCanvas.h"
  11 #include "SkComposeShader.h"
  12 #include "SkGradientShader.h"
  13 #include "SkGraphics.h"
  14 #include "SkShader.h"
  15 #include "SkString.h"
  16 #include "SkXfermode.h"
  17
  18 static SkShader* make_shader(SkXfermode::Mode mode) {
  19     SkPoint pts[2];
  20     SkColor colors[2];
  21
  22     pts[0].set(0, 0);
  23     pts[1].set(SkIntToScalar(100), 0);
  24     colors[0] = SK_ColorRED;
  25     colors[1] = SK_ColorBLUE;
  26     SkAutoTUnref<SkShader> shaderA(SkGradientShader::CreateLinear(pts, colors, NULL, 2,
  27                                                                   SkShader::kClamp_TileMode));
  28
  29     pts[0].set(0, 0);
  30     pts[1].set(0, SkIntToScalar(100));
  31     colors[0] = SK_ColorBLACK;
  32     colors[1] = SkColorSetARGB(0x80, 0, 0, 0);
  33     SkAutoTUnref<SkShader> shaderB(SkGradientShader::CreateLinear(pts, colors, NULL, 2,
  34                                                                   SkShader::kClamp_TileMode));
  35
  36     SkAutoTUnref<SkXfermode> xfer(SkXfermode::Create(mode));
  37
  38     return SkNEW_ARGS(SkComposeShader, (shaderA, shaderB, xfer));
  39 }
  40
  41 class ComposeShaderGM : public skiagm::GM {
  42 public:
  43     ComposeShaderGM() {
  44         fShader = make_shader(SkXfermode::kDstIn_Mode);
  45     }
  46
  47     virtual ~ComposeShaderGM() {
  48         SkSafeUnref(fShader);
  49     }
  50
  51 protected:
  52     SkString onShortName() SK_OVERRIDE {
  53         return SkString("composeshader");
  54     }
  55
  56     SkISize onISize() SK_OVERRIDE {
  57         return SkISize::Make(120, 120);
  58     }
  59
  60     void onDraw(SkCanvas* canvas) SK_OVERRIDE {
  61
  62         SkPaint paint;
  63
  64         paint.setColor(SK_ColorGREEN);
  65         canvas->drawRectCoords(0, 0, SkIntToScalar(100), SkIntToScalar(100), paint);
  66         paint.setShader(fShader);
  67         canvas->drawRectCoords(0, 0, SkIntToScalar(100), SkIntToScalar(100), paint);
  68     }
  69
  70 protected:
  71     SkShader*   fShader;
  72
  73 private:
  74     typedef GM INHERITED ;
  75 };
  76
  77 class ComposeShaderAlphaGM : public skiagm::GM {
  78 public:
  79     ComposeShaderAlphaGM() {}
  80
  81 protected:
  82     SkString onShortName() SK_OVERRIDE {
  83         return SkString("composeshader_alpha");
  84     }
  85
  86     SkISize onISize() SK_OVERRIDE {
  87         return SkISize::Make(220, 750);
  88     }
  89
  90     void onDraw(SkCanvas* canvas) SK_OVERRIDE {
  91         SkAutoTUnref<SkShader> shader0(make_shader(SkXfermode::kDstIn_Mode));
  92         SkAutoTUnref<SkShader> shader1(make_shader(SkXfermode::kSrcOver_Mode));
  93         SkShader* shaders[] = { shader0.get(), shader1.get() };
  94
  95         SkPaint paint;
  96         paint.setColor(SK_ColorGREEN);
  97
  98         const SkRect r = SkRect::MakeXYWH(5, 5, 100, 100);
  99
 100         for (size_t y = 0; y < SK_ARRAY_COUNT(shaders); ++y) {
 101             SkShader* shader = shaders[y];
 102             canvas->save();
 103             for (int alpha = 0xFF; alpha > 0; alpha -= 0x28) {
 104                 paint.setAlpha(0xFF);
 105                 paint.setShader(NULL);
 106                 canvas->drawRect(r, paint);
 107
 108                 paint.setAlpha(alpha);
 109                 paint.setShader(shader);
 110                 canvas->drawRect(r, paint);
 111
 112                 canvas->translate(r.width() + 5, 0);
 113             }
 114             canvas->restore();
 115             canvas->translate(0, r.height() + 5);
 116         }
 117     }
 118 };
 119
 120 //////////////////////////////////////////////////////////////////////////////
 121
 122 DEF_GM( return new ComposeShaderGM; )
 123 DEF_GM( return new ComposeShaderAlphaGM; )