Home | History | Annotate | Download | only in gm 
      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         paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, 2,
     32                                                      SkShader::kClamp_TileMode, flags, nullptr));
     33         canvas->drawRect(r, paint);
     34 
     35         paint.setShader(nullptr);
     36         paint.setStyle(SkPaint::kStroke_Style);
     37         canvas->drawRect(r, paint);
     38     }
     39 
     40     void onDraw(SkCanvas* canvas) override {
     41         constexpr struct {
     42             SkColor fColor0;
     43             SkColor fColor1;
     44         } gRec[] = {
     45             { 0xFFFFFFFF, 0x00000000 },
     46             { 0xFFFFFFFF, 0x00FF0000 },
     47             { 0xFFFFFFFF, 0x00FFFF00 },
     48             { 0xFFFFFFFF, 0x00FFFFFF },
     49             { 0xFFFF0000, 0x00000000 },
     50             { 0xFFFF0000, 0x00FF0000 },
     51             { 0xFFFF0000, 0x00FFFF00 },
     52             { 0xFFFF0000, 0x00FFFFFF },
     53             { 0xFF0000FF, 0x00000000 },
     54             { 0xFF0000FF, 0x00FF0000 },
     55             { 0xFF0000FF, 0x00FFFF00 },
     56             { 0xFF0000FF, 0x00FFFFFF },
     57         };
     58 
     59         SkRect r = SkRect::MakeWH(300, 30);
     60 
     61         canvas->translate(10, 10);
     62 
     63         for (int doPreMul = 0; doPreMul <= 1; ++doPreMul) {
     64             canvas->save();
     65             for (size_t i = 0; i < SK_ARRAY_COUNT(gRec); ++i) {
     66                 draw_grad(canvas, r, gRec[i].fColor0, gRec[i].fColor1, SkToBool(doPreMul));
     67                 canvas->translate(0, r.height() + 8);
     68             }
     69             canvas->restore();
     70             canvas->translate(r.width() + 10, 0);
     71         }
     72     }
     73 
     74 private:
     75     typedef skiagm::GM INHERITED;
     76 };
     77 
     78 DEF_GM(return new AlphaGradientsGM;)
     79