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 "gm.h" 9#include "SkCanvas.h" 10#include "SkColorPriv.h" 11#include "SkShader.h" 12 13#include "SkArithmeticMode.h" 14#include "SkGradientShader.h" 15#define WW 100 16#define HH 32 17 18static SkBitmap make_bm() { 19 SkBitmap bm; 20 bm.allocN32Pixels(WW, HH); 21 bm.eraseColor(SK_ColorTRANSPARENT); 22 return bm; 23} 24 25static SkBitmap make_src() { 26 SkBitmap bm = make_bm(); 27 SkCanvas canvas(bm); 28 SkPaint paint; 29 SkPoint pts[] = { {0, 0}, {SkIntToScalar(WW), SkIntToScalar(HH)} }; 30 SkColor colors[] = { 31 SK_ColorTRANSPARENT, SK_ColorGREEN, SK_ColorCYAN, 32 SK_ColorRED, SK_ColorMAGENTA, SK_ColorWHITE, 33 }; 34 SkShader* s = SkGradientShader::CreateLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors), 35 SkShader::kClamp_TileMode); 36 paint.setShader(s)->unref(); 37 canvas.drawPaint(paint); 38 return bm; 39} 40 41static SkBitmap make_dst() { 42 SkBitmap bm = make_bm(); 43 SkCanvas canvas(bm); 44 SkPaint paint; 45 SkPoint pts[] = { {0, SkIntToScalar(HH)}, {SkIntToScalar(WW), 0} }; 46 SkColor colors[] = { 47 SK_ColorBLUE, SK_ColorYELLOW, SK_ColorBLACK, SK_ColorGREEN, 48 sk_tool_utils::color_to_565(SK_ColorGRAY) 49 }; 50 SkShader* s = SkGradientShader::CreateLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors), 51 SkShader::kClamp_TileMode); 52 paint.setShader(s)->unref(); 53 canvas.drawPaint(paint); 54 return bm; 55} 56 57static void show_k_text(SkCanvas* canvas, SkScalar x, SkScalar y, const SkScalar k[]) { 58 SkPaint paint; 59 paint.setTextSize(SkIntToScalar(24)); 60 paint.setAntiAlias(true); 61 sk_tool_utils::set_portable_typeface(&paint); 62 for (int i = 0; i < 4; ++i) { 63 SkString str; 64 str.appendScalar(k[i]); 65 SkScalar width = paint.measureText(str.c_str(), str.size()); 66 canvas->drawText(str.c_str(), str.size(), x, y + paint.getTextSize(), paint); 67 x += width + SkIntToScalar(10); 68 } 69} 70 71class ArithmodeGM : public skiagm::GM { 72public: 73 ArithmodeGM () {} 74 75protected: 76 77 virtual SkString onShortName() { 78 return SkString("arithmode"); 79 } 80 81 virtual SkISize onISize() { return SkISize::Make(640, 572); } 82 83 virtual void onDraw(SkCanvas* canvas) { 84 SkBitmap src = make_src(); 85 SkBitmap dst = make_dst(); 86 87 const SkScalar one = SK_Scalar1; 88 static const 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 SkScalar y = 0; 105 SkScalar gap = SkIntToScalar(src.width() + 20); 106 while (k < stop) { 107 SkScalar x = 0; 108 canvas->drawBitmap(src, x, y, nullptr); 109 x += gap; 110 canvas->drawBitmap(dst, x, y, nullptr); 111 x += gap; 112 SkRect rect = SkRect::MakeXYWH(x, y, SkIntToScalar(WW), SkIntToScalar(HH)); 113 canvas->saveLayer(&rect, nullptr); 114 canvas->drawBitmap(dst, x, y, nullptr); 115 SkXfermode* xfer = SkArithmeticMode::Create(k[0], k[1], k[2], k[3]); 116 SkPaint paint; 117 paint.setXfermode(xfer)->unref(); 118 canvas->drawBitmap(src, x, y, &paint); 119 canvas->restore(); 120 x += gap; 121 show_k_text(canvas, x, y, k); 122 k += 4; 123 y += SkIntToScalar(src.height() + 12); 124 } 125 126 // Draw two special cases to test enforcePMColor. In these cases, we 127 // draw the dst bitmap twice, the first time it is halved and inverted, 128 // leading to invalid premultiplied colors. If we enforcePMColor, these 129 // invalid values should be clamped, and will not contribute to the 130 // second draw. 131 for (int i = 0; i < 2; i++) { 132 const bool enforcePMColor = (i == 0); 133 SkScalar x = gap; 134 canvas->drawBitmap(dst, x, y, nullptr); 135 x += gap; 136 SkRect rect = SkRect::MakeXYWH(x, y, SkIntToScalar(WW), SkIntToScalar(HH)); 137 canvas->saveLayer(&rect, nullptr); 138 SkXfermode* xfer1 = SkArithmeticMode::Create(0, -one / 2, 0, 1, enforcePMColor); 139 SkPaint paint1; 140 paint1.setXfermode(xfer1)->unref(); 141 canvas->drawBitmap(dst, x, y, &paint1); 142 SkXfermode* xfer2 = SkArithmeticMode::Create(0, one / 2, -one, 1); 143 SkPaint paint2; 144 paint2.setXfermode(xfer2)->unref(); 145 canvas->drawBitmap(dst, x, y, &paint2); 146 canvas->restore(); 147 x += gap; 148 149 // Label 150 SkPaint paint; 151 paint.setTextSize(SkIntToScalar(24)); 152 paint.setAntiAlias(true); 153 sk_tool_utils::set_portable_typeface(&paint); 154 SkString str(enforcePMColor ? "enforcePM" : "no enforcePM"); 155 canvas->drawText(str.c_str(), str.size(), x, y + paint.getTextSize(), paint); 156 157 y += SkIntToScalar(src.height() + 12); 158 } 159 } 160 161private: 162 typedef GM INHERITED; 163}; 164 165/////////////////////////////////////////////////////////////////////////////// 166 167DEF_GM( return new ArithmodeGM; ) 168