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 "SkColorPriv.h"
11 #include "SkPath.h"
12 #include "SkShader.h"
13 #include "SkTextUtils.h"
14 
15 enum {
16     kXfermodeCount = (int)SkBlendMode::kLastMode + 1 + 1,   // extra for arith
17     kShapeSize = 22,
18     kShapeSpacing = 36,
19     kShapeTypeSpacing = 4 * kShapeSpacing / 3,
20     kPaintSpacing = 4 * kShapeTypeSpacing,
21     kLabelSpacing = 3 * kShapeSize,
22     kMargin = kShapeSpacing / 2,
23     kXfermodeTypeSpacing = kLabelSpacing + 2 * kPaintSpacing + kShapeTypeSpacing,
24     kTitleSpacing = 3 * kShapeSpacing / 4,
25     kSubtitleSpacing = 5 * kShapeSpacing / 8
26 };
27 
28 constexpr SkColor kBGColor = 0xc8d2b887;
29 
30 constexpr SkColor kShapeColors[2] = {
31     0x82ff0080,   // input color unknown
32     0xff00ffff,   // input color opaque
33 };
34 
35 enum Shape {
36     kSquare_Shape,
37     kDiamond_Shape,
38     kOval_Shape,
39     kConcave_Shape,
40 
41     kLast_Shape = kConcave_Shape
42 };
43 
44 /**
45  * Verifies AA works properly on all Xfermodes, including arithmetic, with both opaque and unknown
46  * src colors.
47  */
48 class AAXfermodesGM : public skiagm::GM {
49 public:
AAXfermodesGM()50     AAXfermodesGM() {}
51 
52 protected:
53     enum DrawingPass {
54         kCheckerboard_Pass,
55         kBackground_Pass,
56         kShape_Pass
57     };
58 
onShortName()59     SkString onShortName() override {
60         return SkString("aaxfermodes");
61     }
62 
onISize()63     SkISize onISize() override {
64         return SkISize::Make(2 * kMargin + 2 * kXfermodeTypeSpacing -
65                              (kXfermodeTypeSpacing - (kLabelSpacing + 2 * kPaintSpacing)),
66                              2 * kMargin + kTitleSpacing + kSubtitleSpacing +
67                              (1 + (int)SkBlendMode::kLastCoeffMode) * kShapeSpacing);
68     }
69 
onOnceBeforeDraw()70     void onOnceBeforeDraw() override {
71         fLabelFont.setTypeface(sk_tool_utils::create_portable_typeface());
72         fLabelFont.setSize(5 * kShapeSize/8);
73         fLabelFont.setSubpixel(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                 SkTextUtils::DrawString(canvas, "Src Unknown",
110                         kLabelSpacing + kShapeTypeSpacing * 1.5f + kShapeSpacing / 2,
111                         kSubtitleSpacing / 2 + fLabelFont.getSize() / 3, fLabelFont, SkPaint(),
112                                         SkTextUtils::kCenter_Align);
113                 SkTextUtils::DrawString(canvas, "Src Opaque",
114                         kLabelSpacing + kShapeTypeSpacing * 1.5f + kShapeSpacing / 2 +
115                         kPaintSpacing, kSubtitleSpacing / 2 + fLabelFont.getSize() / 3,
116                                         fLabelFont, SkPaint(), SkTextUtils::kCenter_Align);
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         SkFont titleFont(fLabelFont);
180         titleFont.setSize(9 * titleFont.getSize() / 8);
181         titleFont.setEmbolden(true);
182         SkTextUtils::DrawString(canvas, "Porter Duff",
183                                 kLabelSpacing + 4 * kShapeTypeSpacing,
184                                 kTitleSpacing / 2 + titleFont.getSize() / 3, titleFont, SkPaint(),
185                                 SkTextUtils::kCenter_Align);
186         SkTextUtils::DrawString(canvas, "Advanced",
187                                 kXfermodeTypeSpacing + kLabelSpacing + 4 * kShapeTypeSpacing,
188                                 kTitleSpacing / 2 + titleFont.getSize() / 3, titleFont, SkPaint(),
189                                 SkTextUtils::kCenter_Align);
190 
191         draw_pass(canvas, kShape_Pass);
192         canvas->restore();
193     }
194 
drawModeName(SkCanvas * canvas,SkBlendMode mode)195     void drawModeName(SkCanvas* canvas, SkBlendMode mode) {
196         const char* modeName = SkBlendMode_Name(mode);
197         SkTextUtils::DrawString(canvas, modeName, kLabelSpacing - kShapeSize / 4,
198                                 fLabelFont.getSize() / 4, fLabelFont, SkPaint(),
199                                 SkTextUtils::kRight_Align);
200     }
201 
setupShapePaint(SkCanvas * canvas,SkColor color,SkBlendMode mode,SkPaint * paint)202     void setupShapePaint(SkCanvas* canvas, SkColor color, SkBlendMode mode, SkPaint* paint) {
203         paint->setColor(color);
204 
205         if (mode == SkBlendMode::kPlus) {
206             // Check for overflow, otherwise we might get confusing AA artifacts.
207             int maxSum = SkTMax(SkTMax(SkColorGetA(kBGColor) + SkColorGetA(color),
208                                        SkColorGetR(kBGColor) + SkColorGetR(color)),
209                                 SkTMax(SkColorGetG(kBGColor) + SkColorGetG(color),
210                                        SkColorGetB(kBGColor) + SkColorGetB(color)));
211 
212             if (maxSum > 255) {
213                 SkPaint dimPaint;
214                 dimPaint.setAntiAlias(false);
215                 dimPaint.setBlendMode(SkBlendMode::kDstIn);
216                 if (255 != paint->getAlpha()) {
217                     // Dim the src and dst colors.
218                     dimPaint.setARGB(255 * 255 / maxSum, 0, 0, 0);
219                     paint->setAlpha(255 * paint->getAlpha() / maxSum);
220                 } else {
221                     // Just clear the dst, we need to preserve the paint's opacity.
222                     dimPaint.setARGB(0, 0, 0, 0);
223                 }
224                 canvas->drawRect({ -kShapeSpacing/2, -kShapeSpacing/2,
225                                    kShapeSpacing/2 + 3 * kShapeTypeSpacing, kShapeSpacing/2 },
226                                  dimPaint);
227             }
228         }
229     }
230 
drawShape(SkCanvas * canvas,Shape shape,const SkPaint & paint,SkBlendMode mode)231     void drawShape(SkCanvas* canvas, Shape shape, const SkPaint& paint, SkBlendMode mode) {
232         SkASSERT(mode <= SkBlendMode::kLastMode);
233         SkPaint shapePaint(paint);
234         shapePaint.setAntiAlias(kSquare_Shape != shape);
235         shapePaint.setBlendMode(mode);
236 
237         switch (shape) {
238             case kSquare_Shape:
239                 canvas->drawRect({ -kShapeSize/2, -kShapeSize/2, kShapeSize/2, kShapeSize/2 },
240                                  shapePaint);
241                 break;
242 
243             case kDiamond_Shape:
244                 canvas->save();
245                 canvas->rotate(45);
246                 canvas->drawRect({ -kShapeSize/2, -kShapeSize/2, kShapeSize/2, kShapeSize/2 },
247                                  shapePaint);
248                 canvas->restore();
249                 break;
250 
251             case kOval_Shape:
252                 canvas->save();
253                 canvas->rotate(static_cast<SkScalar>((511 * (int)mode + 257) % 360));
254                 canvas->drawPath(fOval, shapePaint);
255                 canvas->restore();
256                 break;
257 
258             case kConcave_Shape:
259                 canvas->drawPath(fConcave, shapePaint);
260                 break;
261 
262             default:
263                 SK_ABORT("Invalid shape.");
264         }
265     }
266 
267 private:
268     SkFont    fLabelFont;
269     SkPath    fOval;
270     SkPath    fConcave;
271 
272     typedef skiagm::GM INHERITED;
273 };
274 DEF_GM( return new AAXfermodesGM; )
275