gm/aaxfermodes.cpp

   1
   2 /*
   3  * Copyright 2015 Google Inc.
   4  *
   5  * Use of this source code is governed by a BSD-style license that can be
   6  * found in the LICENSE file.
   7  */
   8 #include "gm.h"
   9 #include "SkArithmeticMode.h"
  10 #include "SkShader.h"
  11 #include "SkXfermode.h"
  12
  13 enum {
  14     kXfermodeCount = SkXfermode::kLastMode + 2, // All xfermodes plus arithmetic mode.
  15     kShapeSize = 22,
  16     kShapeSpacing = 36,
  17     kShapeTypeSpacing = 4 * kShapeSpacing / 3,
  18     kPaintSpacing = 3 * kShapeTypeSpacing,
  19     kLabelSpacing = 3 * kShapeSize,
  20     kMargin = kShapeSpacing / 2,
  21     kXfermodeTypeSpacing = kLabelSpacing + 2 * kPaintSpacing + kShapeTypeSpacing,
  22     kTitleSpacing = 3 * kShapeSpacing / 4,
  23     kSubtitleSpacing = 5 * kShapeSpacing / 8
  24 };
  25
  26 static const SkColor kBGColor = SkColorSetARGB(200, 210, 184, 135);
  27
  28 static const SkColor kShapeColors[2] = {
  29     SkColorSetARGB(130, 255, 0, 128),   // input color unknown
  30     SkColorSetARGB(255, 0, 255, 255)   // input color opaque
  31 };
  32
  33 enum Shape {
  34     kSquare_Shape,
  35     kDiamond_Shape,
  36     kOval_Shape,
  37
  38     kLast_Shape = kOval_Shape
  39 };
  40
  41 namespace skiagm {
  42
  43 /**
  44  * Verifies AA works properly on all Xfermodes, including arithmetic, with both opaque and unknown
  45  * src colors.
  46  */
  47 class AAXfermodesGM : public GM {
  48 public:
  49     AAXfermodesGM() {}
  50
  51 protected:
  52     enum DrawingPass {
  53         kCheckerboard_Pass,
  54         kBackground_Pass,
  55         kShape_Pass
  56     };
  57
  58     SkString onShortName() override {
  59         return SkString("aaxfermodes");
  60     }
  61
  62     SkISize onISize() override {
  63         return SkISize::Make(2 * kMargin + 2 * kXfermodeTypeSpacing -
  64                              (kXfermodeTypeSpacing - (kLabelSpacing + 2 * kPaintSpacing)),
  65                              2 * kMargin + kTitleSpacing + kSubtitleSpacing +
  66                              (1 + SkXfermode::kLastCoeffMode) * kShapeSpacing);
  67     }
  68
  69     void onOnceBeforeDraw() override {
  70         fLabelPaint.setAntiAlias(true);
  71         sk_tool_utils::set_portable_typeface(&fLabelPaint);
  72         fLabelPaint.setTextSize(5 * kShapeSize/8);
  73         fLabelPaint.setSubpixelText(true);
  74
  75         static const SkScalar radius = -1.4f * kShapeSize/2;
  76         SkPoint pts[4] = {
  77             {-radius, 0},
  78             {0, -1.33f * radius},
  79             {radius, 0},
  80             {0, 1.33f * radius}
  81         };
  82         fPath.moveTo(pts[0]);
  83         fPath.quadTo(pts[1], pts[2]);
  84         fPath.quadTo(pts[3], pts[0]);
  85     }
  86
  87     void draw_pass(SkCanvas* canvas, DrawingPass drawingPass) {
  88         SkRect clipRect =
  89                 { -kShapeSize*11/16, -kShapeSize*11/16, kShapeSize*11/16, kShapeSize*11/16 };
  90
  91         canvas->save();
  92         if (kCheckerboard_Pass == drawingPass) {
  93             canvas->translate(kMargin, kMargin);
  94         }
  95         canvas->translate(0, kTitleSpacing);
  96
  97         for (size_t xfermodeSet = 0; xfermodeSet < 2; xfermodeSet++) {
  98             size_t firstMode = (SkXfermode::kLastCoeffMode + 1) * xfermodeSet;
  99             canvas->save();
 100
 101             if (kShape_Pass == drawingPass) {
 102                 fLabelPaint.setTextAlign(SkPaint::kCenter_Align);
 103                 canvas->drawText("Src Unknown", sizeof("Src Unknown") - 1,
 104                         kLabelSpacing + kShapeSpacing / 2 + kShapeTypeSpacing,
 105                         kSubtitleSpacing / 2 + fLabelPaint.getTextSize() / 3, fLabelPaint);
 106                 canvas->drawText("Src Opaque", sizeof("Src Opaque") - 1,
 107                         kLabelSpacing + kShapeSpacing / 2 + kShapeTypeSpacing + kPaintSpacing,
 108                         kSubtitleSpacing / 2 + fLabelPaint.getTextSize() / 3, fLabelPaint);
 109             }
 110
 111             canvas->translate(0, kSubtitleSpacing + kShapeSpacing/2);
 112
 113             for (size_t m = 0; m <= SkXfermode::kLastCoeffMode; m++) {
 114                 SkXfermode::Mode mode = static_cast<SkXfermode::Mode>(firstMode + m);
 115                 canvas->save();
 116
 117                 if (kShape_Pass == drawingPass) {
 118                     this->drawModeName(canvas, mode);
 119                 }
 120                 canvas->translate(kLabelSpacing + kShapeSpacing/2, 0);
 121
 122                 for (size_t colorIdx = 0; colorIdx < SK_ARRAY_COUNT(kShapeColors); colorIdx++) {
 123                     SkPaint paint;
 124                     this->setupShapePaint(canvas, kShapeColors[colorIdx], mode, &paint);
 125                     SkASSERT(colorIdx == 0 || 255 == paint.getAlpha());
 126                     canvas->save();
 127
 128                     for (size_t shapeIdx = 0; shapeIdx <= kLast_Shape; shapeIdx++) {
 129                         if (kShape_Pass != drawingPass) {
 130                             canvas->save();
 131                             canvas->clipRect(clipRect);
 132                             if (kCheckerboard_Pass == drawingPass) {
 133                                 sk_tool_utils::draw_checkerboard(canvas, 0xffffffff, 0xffc6c3c6,
 134                                         10);
 135                             } else {
 136                                 SkASSERT(kBackground_Pass == drawingPass);
 137                                 canvas->drawColor(kBGColor, SkXfermode::kSrc_Mode);
 138                             }
 139                             canvas->restore();
 140                         } else {
 141                             this->drawShape(canvas, static_cast<Shape>(shapeIdx), paint, mode);
 142                         }
 143                         canvas->translate(kShapeTypeSpacing, 0);
 144                     }
 145
 146                     canvas->restore();
 147                     canvas->translate(kPaintSpacing, 0);
 148                 }
 149
 150                 canvas->restore();
 151                 canvas->translate(0, kShapeSpacing);
 152             }
 153
 154             canvas->restore();
 155             canvas->translate(kXfermodeTypeSpacing, 0);
 156         }
 157
 158         canvas->restore();
 159     }
 160
 161     void onDraw(SkCanvas* canvas) override {
 162         draw_pass(canvas, kCheckerboard_Pass);
 163         canvas->saveLayer(NULL, NULL);
 164
 165         canvas->translate(kMargin, kMargin);
 166         draw_pass(canvas, kBackground_Pass);
 167
 168         SkPaint titlePaint(fLabelPaint);
 169         titlePaint.setTextSize(9 * titlePaint.getTextSize() / 8);
 170         titlePaint.setFakeBoldText(true);
 171         titlePaint.setTextAlign(SkPaint::kCenter_Align);
 172         canvas->drawText("Porter Duff", sizeof("Porter Duff") - 1,
 173                          kLabelSpacing + 3 * kShapeTypeSpacing,
 174                          kTitleSpacing / 2 + titlePaint.getTextSize() / 3, titlePaint);
 175         canvas->drawText("Advanced", sizeof("Advanced") - 1,
 176                          kXfermodeTypeSpacing + kLabelSpacing + 3 * kShapeTypeSpacing,
 177                          kTitleSpacing / 2 + titlePaint.getTextSize() / 3, titlePaint);
 178
 179         draw_pass(canvas, kShape_Pass);
 180         canvas->restore();
 181     }
 182
 183     void drawModeName(SkCanvas* canvas, SkXfermode::Mode mode) {
 184         const char* modeName = mode <= SkXfermode::kLastMode ? SkXfermode::ModeName(mode)
 185                                                              : "Arithmetic";
 186         fLabelPaint.setTextAlign(SkPaint::kRight_Align);
 187         canvas->drawText(modeName, strlen(modeName), kLabelSpacing - kShapeSize / 4,
 188                          fLabelPaint.getTextSize() / 3, fLabelPaint);
 189     }
 190
 191     void setupShapePaint(SkCanvas* canvas, GrColor color, SkXfermode::Mode mode, SkPaint* paint) {
 192         paint->setColor(color);
 193
 194         if (mode == SkXfermode::kPlus_Mode) {
 195             // Check for overflow, otherwise we might get confusing AA artifacts.
 196             int maxSum = SkTMax(SkTMax(SkColorGetA(kBGColor) + SkColorGetA(color),
 197                                        SkColorGetR(kBGColor) + SkColorGetR(color)),
 198                                 SkTMax(SkColorGetG(kBGColor) + SkColorGetG(color),
 199                                        SkColorGetB(kBGColor) + SkColorGetB(color)));
 200
 201             if (maxSum > 255) {
 202                 SkPaint dimPaint;
 203                 dimPaint.setAntiAlias(false);
 204                 dimPaint.setXfermode(SkXfermode::Create(SkXfermode::kDstIn_Mode));
 205                 if (255 != paint->getAlpha()) {
 206                     // Dim the src and dst colors.
 207                     dimPaint.setARGB(255 * 255 / maxSum, 0, 0, 0);
 208                     paint->setAlpha(255 * paint->getAlpha() / maxSum);
 209                 } else {
 210                     // Just clear the dst, we need to preserve the paint's opacity.
 211                     dimPaint.setARGB(0, 0, 0, 0);
 212                 }
 213                 canvas->drawRectCoords(-kShapeSpacing/2, -kShapeSpacing/2,
 214                                        kShapeSpacing/2 + 2 * kShapeTypeSpacing,
 215                                        kShapeSpacing/2, dimPaint);
 216             }
 217         }
 218     }
 219
 220     void drawShape(SkCanvas* canvas, Shape shape, const SkPaint& paint, SkXfermode::Mode mode) {
 221         SkPaint shapePaint(paint);
 222         shapePaint.setAntiAlias(kSquare_Shape != shape);
 223
 224         SkAutoTUnref<SkXfermode> xfermode;
 225         if (mode <= SkXfermode::kLastMode) {
 226             xfermode.reset(SkXfermode::Create(mode));
 227         } else {
 228             xfermode.reset(SkArithmeticMode::Create(+1.0f, +0.25f, -0.5f, +0.1f));
 229         }
 230         shapePaint.setXfermode(xfermode);
 231
 232         switch (shape) {
 233             case kSquare_Shape:
 234                 canvas->drawRectCoords(-kShapeSize/2, -kShapeSize/2, kShapeSize/2, kShapeSize/2,
 235                                        shapePaint);
 236                 break;
 237
 238             case kDiamond_Shape:
 239                 canvas->save();
 240                 canvas->rotate(45);
 241                 canvas->drawRectCoords(-kShapeSize/2, -kShapeSize/2, kShapeSize/2, kShapeSize/2,
 242                                        shapePaint);
 243                 canvas->restore();
 244                 break;
 245
 246             case kOval_Shape:
 247                 canvas->save();
 248                 canvas->rotate(static_cast<SkScalar>((511 * mode + 257) % 360));
 249                 canvas->drawPath(fPath, shapePaint);
 250                 canvas->restore();
 251                 break;
 252
 253             default:
 254                 SkFAIL("Invalid shape.");
 255         }
 256     }
 257
 258 private:
 259     SkPaint   fLabelPaint;
 260     SkPath    fPath;
 261
 262     typedef GM INHERITED;
 263 };
 264
 265 //////////////////////////////////////////////////////////////////////////////
 266
 267 static GM* MyFactory(void*) { return new AAXfermodesGM; }
 268 static GMRegistry reg(MyFactory);
 269
 270 }