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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 #include "sk_tool_utils.h"
10 #include "SkBlendModePriv.h"
11 #include "SkPath.h"
12 #include "SkShader.h"
13 
14 enum {
15     kXfermodeCount = (int)SkBlendMode::kLastMode + 1 + 1,   // extra for arith
16     kShapeSize = 22,
17     kShapeSpacing = 36,
18     kShapeTypeSpacing = 4 * kShapeSpacing / 3,
19     kPaintSpacing = 4 * kShapeTypeSpacing,
20     kLabelSpacing = 3 * kShapeSize,
21     kMargin = kShapeSpacing / 2,
22     kXfermodeTypeSpacing = kLabelSpacing + 2 * kPaintSpacing + kShapeTypeSpacing,
23     kTitleSpacing = 3 * kShapeSpacing / 4,
24     kSubtitleSpacing = 5 * kShapeSpacing / 8
25 };
26 
27 constexpr SkColor kBGColor = 0xc8d2b887;
28 
29 constexpr SkColor kShapeColors[2] = {
30     0x82ff0080,   // input color unknown
31     0xff00ffff,   // input color opaque
32 };
33 
34 enum Shape {
35     kSquare_Shape,
36     kDiamond_Shape,
37     kOval_Shape,
38     kConcave_Shape,
39 
40     kLast_Shape = kConcave_Shape
41 };
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 skiagm::GM {
48 public:
AAXfermodesGM()49     AAXfermodesGM() {}
50 
51 protected:
52     enum DrawingPass {
53         kCheckerboard_Pass,
54         kBackground_Pass,
55         kShape_Pass
56     };
57 
onShortName()58     SkString onShortName() override {
59         return SkString("aaxfermodes");
60     }
61 
onISize()62     SkISize onISize() override {
63         return SkISize::Make(2 * kMargin + 2 * kXfermodeTypeSpacing -
64                              (kXfermodeTypeSpacing - (kLabelSpacing + 2 * kPaintSpacing)),
65                              2 * kMargin + kTitleSpacing + kSubtitleSpacing +
66                              (1 + (int)SkBlendMode::kLastCoeffMode) * kShapeSpacing);
67     }
68 
onOnceBeforeDraw()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         constexpr 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         fOval.moveTo(pts[0]);
83         fOval.quadTo(pts[1], pts[2]);
84         fOval.quadTo(pts[3], pts[0]);
85 
86         fConcave.moveTo(-radius, 0);
87         fConcave.quadTo(0, 0, 0, -radius);
88         fConcave.quadTo(0, 0, radius, 0);
89         fConcave.quadTo(0, 0, 0, radius);
90         fConcave.quadTo(0, 0, -radius, 0);
91         fConcave.close();
92     }
93 
draw_pass(SkCanvas * canvas,DrawingPass drawingPass)94     void draw_pass(SkCanvas* canvas, DrawingPass drawingPass) {
95         SkRect clipRect =
96                 { -kShapeSize*11/16, -kShapeSize*11/16, kShapeSize*11/16, kShapeSize*11/16 };
97 
98         canvas->save();
99         if (kCheckerboard_Pass == drawingPass) {
100             canvas->translate(kMargin, kMargin);
101         }
102         canvas->translate(0, kTitleSpacing);
103 
104         for (size_t xfermodeSet = 0; xfermodeSet < 2; xfermodeSet++) {
105             size_t firstMode = ((size_t)SkBlendMode::kLastCoeffMode + 1) * xfermodeSet;
106             canvas->save();
107 
108             if (kShape_Pass == drawingPass) {
109                 fLabelPaint.setTextAlign(SkPaint::kCenter_Align);
110                 canvas->drawString("Src Unknown",
111                         kLabelSpacing + kShapeTypeSpacing * 1.5f + kShapeSpacing / 2,
112                         kSubtitleSpacing / 2 + fLabelPaint.getTextSize() / 3, fLabelPaint);
113                 canvas->drawString("Src Opaque",
114                         kLabelSpacing + kShapeTypeSpacing * 1.5f + kShapeSpacing / 2 +
115                         kPaintSpacing, kSubtitleSpacing / 2 + fLabelPaint.getTextSize() / 3,
116                         fLabelPaint);
117             }
118 
119             canvas->translate(0, kSubtitleSpacing + kShapeSpacing/2);
120 
121             for (size_t m = 0; m <= (size_t)SkBlendMode::kLastCoeffMode; m++) {
122                 if (firstMode + m > (size_t)SkBlendMode::kLastMode) {
123                     break;
124                 }
125                 SkBlendMode mode = static_cast<SkBlendMode>(firstMode + m);
126                 canvas->save();
127 
128                 if (kShape_Pass == drawingPass) {
129                     this->drawModeName(canvas, mode);
130                 }
131                 canvas->translate(kLabelSpacing + kShapeSpacing/2, 0);
132 
133                 for (size_t colorIdx = 0; colorIdx < SK_ARRAY_COUNT(kShapeColors); colorIdx++) {
134                     SkPaint paint;
135                     this->setupShapePaint(canvas, kShapeColors[colorIdx], mode, &paint);
136                     SkASSERT(colorIdx == 0 || 255 == paint.getAlpha());
137                     canvas->save();
138 
139                     for (size_t shapeIdx = 0; shapeIdx <= kLast_Shape; shapeIdx++) {
140                         if (kShape_Pass != drawingPass) {
141                             canvas->save();
142                             canvas->clipRect(clipRect);
143                             if (kCheckerboard_Pass == drawingPass) {
144                                 sk_tool_utils::draw_checkerboard(canvas, 0xffffffff, 0xffc6c3c6,
145                                         10);
146                             } else {
147                                 SkASSERT(kBackground_Pass == drawingPass);
148                                 canvas->drawColor(kBGColor, SkBlendMode::kSrc);
149                             }
150                             canvas->restore();
151                         } else {
152                             this->drawShape(canvas, static_cast<Shape>(shapeIdx), paint, mode);
153                         }
154                         canvas->translate(kShapeTypeSpacing, 0);
155                     }
156 
157                     canvas->restore();
158                     canvas->translate(kPaintSpacing, 0);
159                 }
160 
161                 canvas->restore();
162                 canvas->translate(0, kShapeSpacing);
163             }
164 
165             canvas->restore();
166             canvas->translate(kXfermodeTypeSpacing, 0);
167         }
168 
169         canvas->restore();
170     }
171 
onDraw(SkCanvas * canvas)172     void onDraw(SkCanvas* canvas) override {
173         draw_pass(canvas, kCheckerboard_Pass);
174         canvas->saveLayer(nullptr, nullptr);
175 
176         canvas->translate(kMargin, kMargin);
177         draw_pass(canvas, kBackground_Pass);
178 
179         SkPaint titlePaint(fLabelPaint);
180         titlePaint.setTextSize(9 * titlePaint.getTextSize() / 8);
181         titlePaint.setFakeBoldText(true);
182         titlePaint.setTextAlign(SkPaint::kCenter_Align);
183         canvas->drawString("Porter Duff",
184                          kLabelSpacing + 4 * kShapeTypeSpacing,
185                          kTitleSpacing / 2 + titlePaint.getTextSize() / 3, titlePaint);
186         canvas->drawString("Advanced",
187                          kXfermodeTypeSpacing + kLabelSpacing + 4 * kShapeTypeSpacing,
188                          kTitleSpacing / 2 + titlePaint.getTextSize() / 3, titlePaint);
189 
190         draw_pass(canvas, kShape_Pass);
191         canvas->restore();
192     }
193 
drawModeName(SkCanvas * canvas,SkBlendMode mode)194     void drawModeName(SkCanvas* canvas, SkBlendMode mode) {
195         const char* modeName = SkBlendMode_Name(mode);
196         fLabelPaint.setTextAlign(SkPaint::kRight_Align);
197         canvas->drawString(modeName, kLabelSpacing - kShapeSize / 4,
198                          fLabelPaint.getTextSize() / 4, fLabelPaint);
199     }
200 
setupShapePaint(SkCanvas * canvas,GrColor color,SkBlendMode mode,SkPaint * paint)201     void setupShapePaint(SkCanvas* canvas, GrColor color, SkBlendMode mode, SkPaint* paint) {
202         paint->setColor(color);
203 
204         if (mode == SkBlendMode::kPlus) {
205             // Check for overflow, otherwise we might get confusing AA artifacts.
206             int maxSum = SkTMax(SkTMax(SkColorGetA(kBGColor) + SkColorGetA(color),
207                                        SkColorGetR(kBGColor) + SkColorGetR(color)),
208                                 SkTMax(SkColorGetG(kBGColor) + SkColorGetG(color),
209                                        SkColorGetB(kBGColor) + SkColorGetB(color)));
210 
211             if (maxSum > 255) {
212                 SkPaint dimPaint;
213                 dimPaint.setAntiAlias(false);
214                 dimPaint.setBlendMode(SkBlendMode::kDstIn);
215                 if (255 != paint->getAlpha()) {
216                     // Dim the src and dst colors.
217                     dimPaint.setARGB(255 * 255 / maxSum, 0, 0, 0);
218                     paint->setAlpha(255 * paint->getAlpha() / maxSum);
219                 } else {
220                     // Just clear the dst, we need to preserve the paint's opacity.
221                     dimPaint.setARGB(0, 0, 0, 0);
222                 }
223                 canvas->drawRect({ -kShapeSpacing/2, -kShapeSpacing/2,
224                                    kShapeSpacing/2 + 3 * kShapeTypeSpacing, kShapeSpacing/2 },
225                                  dimPaint);
226             }
227         }
228     }
229 
drawShape(SkCanvas * canvas,Shape shape,const SkPaint & paint,SkBlendMode mode)230     void drawShape(SkCanvas* canvas, Shape shape, const SkPaint& paint, SkBlendMode mode) {
231         SkASSERT(mode <= SkBlendMode::kLastMode);
232         SkPaint shapePaint(paint);
233         shapePaint.setAntiAlias(kSquare_Shape != shape);
234         shapePaint.setBlendMode(mode);
235 
236         switch (shape) {
237             case kSquare_Shape:
238                 canvas->drawRect({ -kShapeSize/2, -kShapeSize/2, kShapeSize/2, kShapeSize/2 },
239                                  shapePaint);
240                 break;
241 
242             case kDiamond_Shape:
243                 canvas->save();
244                 canvas->rotate(45);
245                 canvas->drawRect({ -kShapeSize/2, -kShapeSize/2, kShapeSize/2, kShapeSize/2 },
246                                  shapePaint);
247                 canvas->restore();
248                 break;
249 
250             case kOval_Shape:
251                 canvas->save();
252                 canvas->rotate(static_cast<SkScalar>((511 * (int)mode + 257) % 360));
253                 canvas->drawPath(fOval, shapePaint);
254                 canvas->restore();
255                 break;
256 
257             case kConcave_Shape:
258                 canvas->drawPath(fConcave, shapePaint);
259                 break;
260 
261             default:
262                 SK_ABORT("Invalid shape.");
263         }
264     }
265 
266 private:
267     SkPaint   fLabelPaint;
268     SkPath    fOval;
269     SkPath    fConcave;
270 
271     typedef skiagm::GM INHERITED;
272 };
273 DEF_GM( return new AAXfermodesGM; )
274