gm/lcdblendmodes.cpp

   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
   9 /*
  10  * Tests text rendering with LCD and the various blend modes.
  11  */
  12
  13 #include "gm.h"
  14 #include "sk_tool_utils.h"
  15 #include "SkCanvas.h"
  16 #include "SkGradientShader.h"
  17 #include "SkSurface.h"
  18
  19 namespace skiagm {
  20
  21 constexpr int kColWidth = 180;
  22 constexpr int kNumCols = 4;
  23 constexpr int kWidth = kColWidth * kNumCols;
  24 constexpr int kHeight = 750;
  25
  26 static sk_sp<SkShader> make_shader(const SkRect& bounds) {
  27     const SkPoint pts[] = {
  28         { bounds.left(), bounds.top() },
  29         { bounds.right(), bounds.bottom() },
  30     };
  31     const SkColor colors[] = {
  32         SK_ColorRED, SK_ColorGREEN,
  33     };
  34     return SkGradientShader::MakeLinear(pts, colors, nullptr, SK_ARRAY_COUNT(colors),
  35                                         SkShader::kRepeat_TileMode);
  36 }
  37
  38 class LcdBlendGM : public skiagm::GM {
  39 public:
  40     LcdBlendGM() {
  41         const int kPointSize = 25;
  42         fTextHeight = SkIntToScalar(kPointSize);
  43     }
  44
  45 protected:
  46     SkString onShortName() override {
  47         return SkString("lcdblendmodes");
  48     }
  49
  50     void onOnceBeforeDraw() override {
  51         fCheckerboard = sk_tool_utils::create_checkerboard_shader(SK_ColorBLACK, SK_ColorWHITE, 4);
  52     }
  53
  54     SkISize onISize() override { return SkISize::Make(kWidth, kHeight); }
  55
  56     void onDraw(SkCanvas* canvas) override {
  57         SkPaint p;
  58         p.setAntiAlias(false);
  59         p.setStyle(SkPaint::kFill_Style);
  60         p.setShader(fCheckerboard);
  61         SkRect r = SkRect::MakeWH(SkIntToScalar(kWidth), SkIntToScalar(kHeight));
  62         canvas->drawRect(r, p);
  63
  64         SkImageInfo info = SkImageInfo::MakeN32Premul(kWidth, kHeight);
  65         auto surface(canvas->makeSurface(info));
  66         if (nullptr == surface) {
  67             surface = SkSurface::MakeRaster(info);
  68         }
  69
  70         SkCanvas* surfCanvas = surface->getCanvas();
  71         this->drawColumn(surfCanvas, SK_ColorBLACK, SK_ColorWHITE, false);
  72         surfCanvas->translate(SkIntToScalar(kColWidth), 0);
  73         this->drawColumn(surfCanvas, SK_ColorWHITE, SK_ColorBLACK, false);
  74         surfCanvas->translate(SkIntToScalar(kColWidth), 0);
  75         this->drawColumn(surfCanvas, SK_ColorGREEN, SK_ColorMAGENTA, false);
  76         surfCanvas->translate(SkIntToScalar(kColWidth), 0);
  77         this->drawColumn(surfCanvas, SK_ColorCYAN, SK_ColorMAGENTA, true);
  78
  79         SkPaint surfPaint;
  80         surfPaint.setBlendMode(SkBlendMode::kSrcOver);
  81         surface->draw(canvas, 0, 0, &surfPaint);
  82     }
  83
  84     void drawColumn(SkCanvas* canvas, SkColor backgroundColor, SkColor textColor, bool useGrad) {
  85         const SkBlendMode gModes[] = {
  86             SkBlendMode::kClear,
  87             SkBlendMode::kSrc,
  88             SkBlendMode::kDst,
  89             SkBlendMode::kSrcOver,
  90             SkBlendMode::kDstOver,
  91             SkBlendMode::kSrcIn,
  92             SkBlendMode::kDstIn,
  93             SkBlendMode::kSrcOut,
  94             SkBlendMode::kDstOut,
  95             SkBlendMode::kSrcATop,
  96             SkBlendMode::kDstATop,
  97             SkBlendMode::kXor,
  98             SkBlendMode::kPlus,
  99             SkBlendMode::kModulate,
 100             SkBlendMode::kScreen,
 101             SkBlendMode::kOverlay,
 102             SkBlendMode::kDarken,
 103             SkBlendMode::kLighten,
 104             SkBlendMode::kColorDodge,
 105             SkBlendMode::kColorBurn,
 106             SkBlendMode::kHardLight,
 107             SkBlendMode::kSoftLight,
 108             SkBlendMode::kDifference,
 109             SkBlendMode::kExclusion,
 110             SkBlendMode::kMultiply,
 111             SkBlendMode::kHue,
 112             SkBlendMode::kSaturation,
 113             SkBlendMode::kColor,
 114             SkBlendMode::kLuminosity,
 115         };
 116         // Draw background rect
 117         SkPaint backgroundPaint;
 118         backgroundPaint.setColor(backgroundColor);
 119         canvas->drawRect(SkRect::MakeIWH(kColWidth, kHeight), backgroundPaint);
 120         SkScalar y = fTextHeight;
 121         for (size_t m = 0; m < SK_ARRAY_COUNT(gModes); m++) {
 122             SkPaint paint;
 123             paint.setColor(textColor);
 124             paint.setAntiAlias(true);
 125             paint.setSubpixelText(true);
 126             paint.setLCDRenderText(true);
 127             paint.setTextSize(fTextHeight);
 128             paint.setBlendMode(gModes[m]);
 129             sk_tool_utils::set_portable_typeface(&paint);
 130             if (useGrad) {
 131                 SkRect r;
 132                 r.setXYWH(0, y - fTextHeight, SkIntToScalar(kColWidth), fTextHeight);
 133                 paint.setShader(make_shader(r));
 134             }
 135             SkString string(SkBlendMode_Name(gModes[m]));
 136             canvas->drawString(string, 0, y, paint);
 137             y+=fTextHeight;
 138         }
 139     }
 140
 141 private:
 142     SkScalar fTextHeight;
 143     sk_sp<SkShader> fCheckerboard;
 144     typedef skiagm::GM INHERITED;
 145 };
 146
 147 //////////////////////////////////////////////////////////////////////////////
 148
 149 DEF_GM( return new LcdBlendGM; )
 150 }