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      1 /*
      2  * Copyright 2013 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 "SkCanvas.h"
     10 #include "SkGradientShader.h"
     11 
     12 class AlphaGradientsGM : public skiagm::GM {
     13 public:
     14     AlphaGradientsGM() {}
     15 
     16 protected:
     17     virtual SkString onShortName() SK_OVERRIDE {
     18         return SkString("alphagradients");
     19     }
     20 
     21     virtual SkISize onISize() SK_OVERRIDE {
     22         return SkISize::Make(640, 480);
     23     }
     24 
     25     static void draw_grad(SkCanvas* canvas, const SkRect& r,
     26                           SkColor c0, SkColor c1, bool doPreMul) {
     27         SkColor colors[] = { c0, c1 };
     28         SkPoint pts[] = { { r.fLeft, r.fTop }, { r.fRight, r.fBottom } };
     29         SkPaint paint;
     30         uint32_t flags = doPreMul ? SkGradientShader::kInterpolateColorsInPremul_Flag : 0;
     31         SkShader* s = SkGradientShader::CreateLinear(pts, colors, NULL, 2,
     32                                                      SkShader::kClamp_TileMode, flags, NULL);
     33         paint.setShader(s)->unref();
     34         canvas->drawRect(r, paint);
     35 
     36         paint.setShader(NULL);
     37         paint.setStyle(SkPaint::kStroke_Style);
     38         canvas->drawRect(r, paint);
     39     }
     40 
     41     virtual void onDraw(SkCanvas* canvas) SK_OVERRIDE {
     42         static const struct {
     43             SkColor fColor0;
     44             SkColor fColor1;
     45         } gRec[] = {
     46             { 0xFFFFFFFF, 0x00000000 },
     47             { 0xFFFFFFFF, 0x00FF0000 },
     48             { 0xFFFFFFFF, 0x00FFFF00 },
     49             { 0xFFFFFFFF, 0x00FFFFFF },
     50             { 0xFFFF0000, 0x00000000 },
     51             { 0xFFFF0000, 0x00FF0000 },
     52             { 0xFFFF0000, 0x00FFFF00 },
     53             { 0xFFFF0000, 0x00FFFFFF },
     54             { 0xFF0000FF, 0x00000000 },
     55             { 0xFF0000FF, 0x00FF0000 },
     56             { 0xFF0000FF, 0x00FFFF00 },
     57             { 0xFF0000FF, 0x00FFFFFF },
     58         };
     59 
     60         SkRect r = SkRect::MakeWH(300, 30);
     61 
     62         canvas->translate(10, 10);
     63 
     64         for (int doPreMul = 0; doPreMul <= 1; ++doPreMul) {
     65             canvas->save();
     66             for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) {
     67                 draw_grad(canvas, r, gRec[i].fColor0, gRec[i].fColor1, SkToBool(doPreMul));
     68                 canvas->translate(0, r.height() + 8);
     69             }
     70             canvas->restore();
     71             canvas->translate(r.width() + 10, 0);
     72         }
     73     }
     74 
     75     virtual uint32_t onGetFlags() const { return kSkipPipe_Flag | kSkipTiled_Flag; }
     76 
     77 private:
     78     typedef skiagm::GM INHERITED;
     79 };
     80 
     81 DEF_GM( return SkNEW(AlphaGradientsGM); )
     82