1 /* 2 * Copyright 2015 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 10 #include "SkShader.h" 11 12 // This class of GMs test how edges/verts snap near rounding boundaries in device space without 13 // anti-aliaing. 14 class PixelSnapGM : public skiagm::GM { 15 public: PixelSnapGM()16 PixelSnapGM() {} 17 18 protected: 19 // kTrans should be even or checkboards wont agree in different test cases. 20 static const int kTrans = 14; 21 static const int kLabelPad = 4; 22 // The inverse of this value should be a perfect SkScalar. 23 static const int kSubPixelSteps = 8; 24 static const int kLabelTextSize = 9; 25 26 SK_COMPILE_ASSERT(kSubPixelSteps < 99, label_offset_too_small); 27 static const int kLabelOffsetX = 2 * kLabelTextSize + kLabelPad; 28 static const int kLabelOffsetY = kLabelTextSize + kLabelPad; 29 onISize()30 SkISize onISize() override { 31 return SkISize::Make((kSubPixelSteps + 1) * kTrans + kLabelOffsetX + kLabelPad, 32 (kSubPixelSteps + 1) * kTrans + kLabelOffsetY + kLabelPad); 33 } 34 onDraw(SkCanvas * canvas)35 void onDraw(SkCanvas* canvas) override { 36 SkPaint bgPaint; 37 bgPaint.setShader( 38 sk_tool_utils::create_checkerboard_shader(0xFFAAAAAA, 0xFF777777, 1))->unref(); 39 canvas->drawPaint(bgPaint); 40 41 SkString offset; 42 SkPaint labelPaint; 43 labelPaint.setAntiAlias(true); 44 labelPaint.setColor(SK_ColorWHITE); 45 labelPaint.setTextSize(SkIntToScalar(kLabelTextSize)); 46 SkPaint linePaint; 47 linePaint.setColor(SK_ColorWHITE); 48 49 // Drawing labels is useful for debugging, but bad for baselining (x-platform txt diffs). 50 if (false) { 51 // Draw row labels 52 canvas->save(); 53 canvas->translate(0, SkIntToScalar(kLabelOffsetY)); 54 for (int i = 0; i <= kSubPixelSteps; ++i) { 55 offset.printf("%d", i); 56 canvas->drawText(offset.c_str(), offset.size(), 57 0, i * kTrans + labelPaint.getTextSize(), 58 labelPaint); 59 } 60 canvas->restore(); 61 62 // Draw col labels 63 canvas->save(); 64 canvas->translate(SkIntToScalar(kLabelOffsetX), 0); 65 for (int i = 0; i <= kSubPixelSteps; ++i) { 66 offset.printf("%d", i); 67 canvas->drawText(offset.c_str(), offset.size(), 68 i * SkIntToScalar(kTrans), labelPaint.getTextSize(), 69 labelPaint); 70 } 71 canvas->restore(); 72 } 73 74 canvas->translate(SkIntToScalar(kLabelOffsetX), SkIntToScalar(kLabelOffsetY)); 75 76 // Draw test case grid lines (Draw them all at pixel centers to hopefully avoid any 77 // snapping issues). 78 for (int i = 0; i <= kSubPixelSteps + 1; ++i) { 79 canvas->drawLine(0.5f, 80 i * SkIntToScalar(kTrans) + 0.5f, 81 SkIntToScalar(kTrans) * (kSubPixelSteps + 1) + 0.5f, 82 i * SkIntToScalar(kTrans) + 0.5f, 83 linePaint); 84 canvas->drawLine(i * SkIntToScalar(kTrans) + 0.5f, 85 0.5f, 86 i * SkIntToScalar(kTrans) + 0.5f, 87 SkIntToScalar(kTrans) * (kSubPixelSteps + 1) + 0.5f, 88 linePaint); 89 } 90 91 for (int i = 0; i <= kSubPixelSteps; ++i) { 92 for (int j = 0; j <= kSubPixelSteps; ++j) { 93 canvas->save(); 94 // +1's account for the grid lines around each test case. 95 canvas->translate(j * (kTrans + 1.f/kSubPixelSteps) + 1, 96 i * (kTrans + 1.f/kSubPixelSteps) + 1); 97 this->drawElement(canvas); 98 canvas->restore(); 99 } 100 } 101 } 102 103 virtual void drawElement(SkCanvas*) = 0; 104 105 private: 106 typedef skiagm::GM INHERITED; 107 }; 108 109 class PointSnapGM : public PixelSnapGM { 110 protected: onShortName()111 SkString onShortName() override { return SkString("pixel_snap_point"); } drawElement(SkCanvas * canvas)112 void drawElement(SkCanvas* canvas) override { canvas->drawPoint(1, 1, SK_ColorBLUE); } 113 114 private: 115 typedef PixelSnapGM INHERITED; 116 }; 117 118 class LineSnapGM : public PixelSnapGM { 119 protected: onShortName()120 SkString onShortName() override { return SkString("pixel_snap_line"); } drawElement(SkCanvas * canvas)121 void drawElement(SkCanvas* canvas) override { 122 SkPaint paint; 123 paint.setColor(SK_ColorGREEN); 124 // Draw a horizontal and vertical line, each length 3. 125 canvas->drawLine(1, 1, 4, 1, paint); 126 canvas->drawLine(6, 1, 6, 4, paint); 127 } 128 129 private: 130 typedef PixelSnapGM INHERITED; 131 }; 132 133 class RectSnapGM : public PixelSnapGM { 134 protected: onShortName()135 SkString onShortName() override { return SkString("pixel_snap_rect"); } drawElement(SkCanvas * canvas)136 void drawElement(SkCanvas* canvas) override { 137 SkPaint paint; 138 paint.setColor(SK_ColorRED); 139 canvas->drawRect(SkRect::MakeXYWH(1, 1, 3, 3), paint); 140 } 141 142 private: 143 typedef PixelSnapGM INHERITED; 144 }; 145 146 class ComboSnapGM : public PixelSnapGM { 147 protected: onShortName()148 SkString onShortName() override { return SkString("pixel_snap_combo"); } drawElement(SkCanvas * canvas)149 void drawElement(SkCanvas* canvas) override { 150 SkPaint paint; 151 paint.setAntiAlias(false); 152 // A rectangle that exactly covers a pixel, a point at each corner, 8 horiz/vert lines 153 // at rect corners (two at each corner, extending away from rect). They are drawn in this 154 // order lines (green), points (blue), rect(red). 155 SkRect rect = SkRect::MakeXYWH(3, 3, 1, 1); 156 paint.setColor(SK_ColorGREEN); 157 canvas->drawLine(3, 3, 0, 3, paint); 158 canvas->drawLine(3, 3, 3, 0, paint); 159 canvas->drawLine(4, 3, 7, 3, paint); 160 canvas->drawLine(4, 3, 4, 0, paint); 161 canvas->drawLine(3, 4, 0, 4, paint); 162 canvas->drawLine(3, 4, 3, 7, paint); 163 canvas->drawLine(4, 4, 7, 4, paint); 164 canvas->drawLine(4, 4, 4, 7, paint); 165 canvas->drawPoint(4, 3, SK_ColorBLUE); 166 canvas->drawPoint(4, 4, SK_ColorBLUE); 167 canvas->drawPoint(3, 3, SK_ColorBLUE); 168 canvas->drawPoint(3, 4, SK_ColorBLUE); 169 paint.setColor(SK_ColorRED); 170 canvas->drawRect(rect, paint); 171 } 172 173 private: 174 typedef PixelSnapGM INHERITED; 175 }; 176 177 ////////////////////////////////////////////////////////////////////////////// 178 DEF_GM( return SkNEW(PointSnapGM); ) 179 DEF_GM( return SkNEW(LineSnapGM); ) 180 DEF_GM( return SkNEW(RectSnapGM); ) 181 DEF_GM( return SkNEW(ComboSnapGM); ) 182