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      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     virtual uint32_t onGetFlags() const SK_OVERRIDE {
     53         return kSkipTiled_Flag;
     54     }
     55 
     56     virtual SkString onShortName() SK_OVERRIDE {
     57         return SkString("composeshader");
     58     }
     59 
     60     virtual SkISize onISize() SK_OVERRIDE {
     61         return SkISize::Make(120, 120);
     62     }
     63 
     64     virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
     65 
     66         SkPaint paint;
     67 
     68         paint.setColor(SK_ColorGREEN);
     69         canvas->drawRectCoords(0, 0, SkIntToScalar(100), SkIntToScalar(100), paint);
     70         paint.setShader(fShader);
     71         canvas->drawRectCoords(0, 0, SkIntToScalar(100), SkIntToScalar(100), paint);
     72     }
     73 
     74 protected:
     75     SkShader*   fShader;
     76 
     77 private:
     78     typedef GM INHERITED ;
     79 };
     80 
     81 class ComposeShaderAlphaGM : public skiagm::GM {
     82 public:
     83     ComposeShaderAlphaGM() {}
     84 
     85 protected:
     86     virtual SkString onShortName() SK_OVERRIDE {
     87         return SkString("composeshader_alpha");
     88     }
     89 
     90     virtual SkISize onISize() SK_OVERRIDE {
     91         return SkISize::Make(220, 750);
     92     }
     93 
     94     virtual uint32_t onGetFlags() const SK_OVERRIDE {
     95         // we're only off by 1 bit per-component
     96         return kSkipTiled_Flag;
     97     }
     98 
     99     virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
    100         SkAutoTUnref<SkShader> shader0(make_shader(SkXfermode::kDstIn_Mode));
    101         SkAutoTUnref<SkShader> shader1(make_shader(SkXfermode::kSrcOver_Mode));
    102         SkShader* shaders[] = { shader0.get(), shader1.get() };
    103 
    104         SkPaint paint;
    105         paint.setColor(SK_ColorGREEN);
    106 
    107         const SkRect r = SkRect::MakeXYWH(5, 5, 100, 100);
    108 
    109         for (size_t y = 0; y < SK_ARRAY_COUNT(shaders); ++y) {
    110             SkShader* shader = shaders[y];
    111             canvas->save();
    112             for (int alpha = 0xFF; alpha > 0; alpha -= 0x28) {
    113                 paint.setAlpha(0xFF);
    114                 paint.setShader(NULL);
    115                 canvas->drawRect(r, paint);
    116 
    117                 paint.setAlpha(alpha);
    118                 paint.setShader(shader);
    119                 canvas->drawRect(r, paint);
    120 
    121                 canvas->translate(r.width() + 5, 0);
    122             }
    123             canvas->restore();
    124             canvas->translate(0, r.height() + 5);
    125         }
    126     }
    127 };
    128 
    129 //////////////////////////////////////////////////////////////////////////////
    130 
    131 DEF_GM( return new ComposeShaderGM; )
    132 DEF_GM( return new ComposeShaderAlphaGM; )
    133