gm/alphagradients.cpp

   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     SkString onShortName() override {
  18         return SkString("alphagradients");
  19     }
  20
  21     SkISize onISize() 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     void onDraw(SkCanvas* canvas) 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 private:
  76     typedef skiagm::GM INHERITED;
  77 };
  78
  79 DEF_GM( return SkNEW(AlphaGradientsGM); )