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 <SkFont.h> 9 #include "gm.h" 10 #include "sk_tool_utils.h" 11 #include "SkArithmeticImageFilter.h" 12 #include "SkCanvas.h" 13 #include "SkColorPriv.h" 14 #include "SkGradientShader.h" 15 #include "SkImage.h" 16 #include "SkImageSource.h" 17 #include "SkShader.h" 18 #include "SkSurface.h" 19 20 #define WW 100 21 #define HH 32 22 23 static sk_sp<SkImage> make_src() { 24 sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(WW, HH)); 25 SkCanvas* canvas = surface->getCanvas(); 26 27 SkPaint paint; 28 SkPoint pts[] = { {0, 0}, {SkIntToScalar(WW), SkIntToScalar(HH)} }; 29 SkColor colors[] = { 30 SK_ColorTRANSPARENT, SK_ColorGREEN, SK_ColorCYAN, 31 SK_ColorRED, SK_ColorMAGENTA, SK_ColorWHITE, 32 }; 33 paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors), 34 SkShader::kClamp_TileMode)); 35 canvas->drawPaint(paint); 36 return surface->makeImageSnapshot(); 37 } 38 39 static sk_sp<SkImage> make_dst() { 40 sk_sp<SkSurface> surface(SkSurface::MakeRasterN32Premul(WW, HH)); 41 SkCanvas* canvas = surface->getCanvas(); 42 43 SkPaint paint; 44 SkPoint pts[] = { {0, SkIntToScalar(HH)}, {SkIntToScalar(WW), 0} }; 45 SkColor colors[] = { 46 SK_ColorBLUE, SK_ColorYELLOW, SK_ColorBLACK, SK_ColorGREEN, 47 SK_ColorGRAY, 48 }; 49 paint.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors), 50 SkShader::kClamp_TileMode)); 51 canvas->drawPaint(paint); 52 return surface->makeImageSnapshot(); 53 } 54 55 static void show_k_text(SkCanvas* canvas, SkScalar x, SkScalar y, const SkScalar k[]) { 56 SkFont font(sk_tool_utils::create_portable_typeface(), 24); 57 font.setEdging(SkFont::Edging::kAntiAlias); 58 SkPaint paint; 59 paint.setAntiAlias(true); 60 for (int i = 0; i < 4; ++i) { 61 SkString str; 62 str.appendScalar(k[i]); 63 SkScalar width = font.measureText(str.c_str(), str.size(), kUTF8_SkTextEncoding); 64 canvas->drawString(str, x, y + font.getSize(), font, paint); 65 x += width + SkIntToScalar(10); 66 } 67 } 68 69 class ArithmodeGM : public skiagm::GM { 70 public: 71 ArithmodeGM () {} 72 73 protected: 74 75 virtual SkString onShortName() { 76 return SkString("arithmode"); 77 } 78 79 virtual SkISize onISize() { return SkISize::Make(640, 572); } 80 81 virtual void onDraw(SkCanvas* canvas) { 82 sk_sp<SkImage> src = make_src(); 83 sk_sp<SkImage> dst = make_dst(); 84 sk_sp<SkImageFilter> srcFilter = SkImageSource::Make(src); 85 sk_sp<SkImageFilter> dstFilter = SkImageSource::Make(dst); 86 87 constexpr SkScalar one = SK_Scalar1; 88 constexpr SkScalar K[] = { 89 0, 0, 0, 0, 90 0, 0, 0, one, 91 0, one, 0, 0, 92 0, 0, one, 0, 93 0, one, one, 0, 94 0, one, -one, 0, 95 0, one/2, one/2, 0, 96 0, one/2, one/2, one/4, 97 0, one/2, one/2, -one/4, 98 one/4, one/2, one/2, 0, 99 -one/4, one/2, one/2, 0, 100 }; 101 102 const SkScalar* k = K; 103 const SkScalar* stop = k + SK_ARRAY_COUNT(K); 104 const SkRect rect = SkRect::MakeWH(WW, HH); 105 SkScalar gap = SkIntToScalar(WW + 20); 106 while (k < stop) { 107 { 108 SkAutoCanvasRestore acr(canvas, true); 109 canvas->drawImage(src, 0, 0); 110 canvas->translate(gap, 0); 111 canvas->drawImage(dst, 0, 0); 112 canvas->translate(gap, 0); 113 SkPaint paint; 114 paint.setImageFilter(SkArithmeticImageFilter::Make(k[0], k[1], k[2], k[3], true, 115 dstFilter, srcFilter, nullptr)); 116 canvas->saveLayer(&rect, &paint); 117 canvas->restore(); 118 119 canvas->translate(gap, 0); 120 show_k_text(canvas, 0, 0, k); 121 } 122 123 k += 4; 124 canvas->translate(0, HH + 12); 125 } 126 127 // Draw two special cases to test enforcePMColor. In these cases, we 128 // draw the dst bitmap twice, the first time it is halved and inverted, 129 // leading to invalid premultiplied colors. If we enforcePMColor, these 130 // invalid values should be clamped, and will not contribute to the 131 // second draw. 132 for (int i = 0; i < 2; i++) { 133 const bool enforcePMColor = (i == 0); 134 135 { 136 SkAutoCanvasRestore acr(canvas, true); 137 canvas->translate(gap, 0); 138 canvas->drawImage(dst, 0, 0); 139 canvas->translate(gap, 0); 140 141 sk_sp<SkImageFilter> bg = 142 SkArithmeticImageFilter::Make(0, 0, -one / 2, 1, enforcePMColor, dstFilter, 143 nullptr, nullptr); 144 SkPaint p; 145 p.setImageFilter(SkArithmeticImageFilter::Make(0, one / 2, -one, 1, true, 146 std::move(bg), dstFilter, nullptr)); 147 canvas->saveLayer(&rect, &p); 148 canvas->restore(); 149 canvas->translate(gap, 0); 150 151 // Label 152 SkFont font(sk_tool_utils::create_portable_typeface(), 24); 153 SkString str(enforcePMColor ? "enforcePM" : "no enforcePM"); 154 canvas->drawString(str, 0, font.getSize(), font, SkPaint()); 155 } 156 canvas->translate(0, HH + 12); 157 } 158 } 159 160 private: 161 typedef GM INHERITED; 162 }; 163 164 /////////////////////////////////////////////////////////////////////////////// 165 166 DEF_GM( return new ArithmodeGM; ) 167
