1 /*
2 * Copyright 2011 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 "include/core/SkCanvas.h"
9 #include "include/core/SkShader.h"
10 #include "include/effects/SkGradientShader.h"
11 #include "samplecode/DecodeFile.h"
12 #include "samplecode/Sample.h"
13 #include "tools/Resources.h"
14
15 namespace {
make_bitmapfade(const SkBitmap & bm)16 static sk_sp<SkShader> make_bitmapfade(const SkBitmap& bm) {
17 SkPoint pts[2] = {
18 {0, 0},
19 {0, (float)bm.height()},
20 };
21 SkColor colors[2] = {
22 SkColorSetARGB(255, 0, 0, 0),
23 SkColorSetARGB(0, 0, 0, 0),
24 };
25 return SkShaders::Blend(SkBlendMode::kDstIn,
26 bm.makeShader(),
27 SkGradientShader::MakeLinear(pts, colors, nullptr, 2,
28 SkTileMode::kClamp));
29 }
30
make_blend_shader()31 static sk_sp<SkShader> make_blend_shader() {
32 SkPoint pts[2];
33 SkColor colors[2];
34
35 pts[0].set(0, 0);
36 pts[1].set(SkIntToScalar(100), 0);
37 colors[0] = SK_ColorRED;
38 colors[1] = SK_ColorBLUE;
39 auto shaderA = SkGradientShader::MakeLinear(pts, colors, nullptr, 2, SkTileMode::kClamp);
40
41 pts[0].set(0, 0);
42 pts[1].set(0, SkIntToScalar(100));
43 colors[0] = SK_ColorBLACK;
44 colors[1] = SkColorSetARGB(0x80, 0, 0, 0);
45 auto shaderB = SkGradientShader::MakeLinear(pts, colors, nullptr, 2, SkTileMode::kClamp);
46
47 return SkShaders::Blend(SkBlendMode::kDstIn, std::move(shaderA), std::move(shaderB));
48 }
49
50 struct ShaderView : public Sample {
51 sk_sp<SkShader> fShader;
52 sk_sp<SkShader> fShaderFade;
53 SkBitmap fBitmap;
54
onOnceBeforeDraw__anon75dc86790111::ShaderView55 void onOnceBeforeDraw() override {
56 decode_file(GetResourceAsData("images/dog.jpg"), &fBitmap);
57 fShader = make_blend_shader();
58 fShaderFade = make_bitmapfade(fBitmap);
59 }
60
name__anon75dc86790111::ShaderView61 SkString name() override { return SkString("Shaders"); }
62
onDrawContent__anon75dc86790111::ShaderView63 void onDrawContent(SkCanvas* canvas) override {
64 canvas->drawBitmap(fBitmap, 0, 0);
65 canvas->translate(20, 120);
66
67 SkPaint paint;
68 paint.setColor(SK_ColorGREEN);
69 canvas->drawRect(SkRect{0, 0, 100, 100}, paint);
70 paint.setShader(fShader);
71 canvas->drawRect(SkRect{0, 0, 100, 100}, paint);
72
73 canvas->translate(SkIntToScalar(110), 0);
74
75 paint.setShader(nullptr);
76 canvas->drawRect(SkRect{0, 0, 120, 80}, paint);
77 paint.setShader(fShaderFade);
78 canvas->drawRect(SkRect{0, 0, 120, 80}, paint);
79 }
80 };
81 } // namespace
82 DEF_SAMPLE( return new ShaderView(); )
83
