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1 
2 /*
3  * Copyright 2017 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 "samplecode/Sample.h"
9 #include "tools/Resources.h"
10 
11 #include "include/core/SkCanvas.h"
12 #include "include/core/SkFont.h"
13 #include "include/core/SkImage.h"
14 #include "include/core/SkPath.h"
15 #include "include/core/SkPoint3.h"
16 #include "include/utils/SkShadowUtils.h"
17 
18 ////////////////////////////////////////////////////////////////////////////
19 // Sample to demonstrate tonal color shadows
20 
21 class ShadowColorView : public Sample {
22     SkPath    fRectPath;
23     int       fZIndex;
24 
25     bool      fShowAmbient;
26     bool      fShowSpot;
27     bool      fUseAlt;
28     bool      fShowObject;
29     bool      fTwoPassColor;
30     bool      fDarkBackground;
31 
32 public:
ShadowColorView()33     ShadowColorView()
34         : fZIndex(8)
35         , fShowAmbient(true)
36         , fShowSpot(true)
37         , fUseAlt(false)
38         , fShowObject(true)
39         , fTwoPassColor(false)
40         , fDarkBackground(false) {}
41 
42 protected:
onOnceBeforeDraw()43     void onOnceBeforeDraw() override {
44         fRectPath.addRect(SkRect::MakeXYWH(-50, -50, 100, 100));
45     }
46 
name()47     SkString name() override { return SkString("ShadowColor"); }
48 
onChar(SkUnichar uni)49     bool onChar(SkUnichar uni) override {
50             bool handled = false;
51             switch (uni) {
52                 case 'W':
53                     fShowAmbient = !fShowAmbient;
54                     handled = true;
55                     break;
56                 case 'S':
57                     fShowSpot = !fShowSpot;
58                     handled = true;
59                     break;
60                 case 'T':
61                     fUseAlt = !fUseAlt;
62                     handled = true;
63                     break;
64                 case 'O':
65                     fShowObject = !fShowObject;
66                     handled = true;
67                     break;
68                 case 'X':
69                     fTwoPassColor = !fTwoPassColor;
70                     handled = true;
71                     break;
72                 case 'Z':
73                     fDarkBackground = !fDarkBackground;
74                     handled = true;
75                     break;
76                 case '>':
77                     fZIndex = SkTMin(9, fZIndex+1);
78                     handled = true;
79                     break;
80                 case '<':
81                     fZIndex = SkTMax(0, fZIndex-1);
82                     handled = true;
83                     break;
84                 default:
85                     break;
86             }
87             if (handled) {
88                 return true;
89             }
90             return false;
91     }
92 
93 
drawShadowedPath(SkCanvas * canvas,const SkPath & path,const SkPoint3 & zPlaneParams,const SkPaint & paint,SkScalar ambientAlpha,const SkPoint3 & lightPos,SkScalar lightWidth,SkScalar spotAlpha)94     void drawShadowedPath(SkCanvas* canvas, const SkPath& path,
95                           const SkPoint3& zPlaneParams,
96                           const SkPaint& paint, SkScalar ambientAlpha,
97                           const SkPoint3& lightPos, SkScalar lightWidth, SkScalar spotAlpha) {
98         if (!fShowAmbient) {
99             ambientAlpha = 0;
100         }
101         if (!fShowSpot) {
102             spotAlpha = 0;
103         }
104         uint32_t flags = 0;
105         if (fUseAlt) {
106             flags |= SkShadowFlags::kGeometricOnly_ShadowFlag;
107         }
108 
109         if (fTwoPassColor) {
110             SkColor ambientColor = SkColorSetARGB(ambientAlpha*255, 0, 0, 0);
111             SkShadowUtils::DrawShadow(canvas, path, zPlaneParams,
112                                       lightPos, lightWidth,
113                                       ambientColor, SK_ColorTRANSPARENT, flags);
114 
115             if (paint.getColor() != SK_ColorBLACK) {
116                 SkColor color = paint.getColor();
117 
118                 uint8_t max = SkTMax(SkTMax(SkColorGetR(color), SkColorGetG(color)),
119                                      SkColorGetB(color));
120                 uint8_t min = SkTMin(SkTMin(SkColorGetR(color), SkColorGetG(color)),
121                                      SkColorGetB(color));
122                 SkScalar luminance = 0.5f*(max + min) / 255.f;
123                 SkScalar alpha = (.6 - .4*luminance)*luminance*luminance + 0.3f;
124                 spotAlpha -= (alpha - 0.3f)*.5f;
125                 SkColor spotColor = SkColorSetARGB(alpha*SkColorGetA(color), SkColorGetR(color),
126                                                    SkColorGetG(color), SkColorGetB(color));
127 
128                 SkShadowUtils::DrawShadow(canvas, path, zPlaneParams,
129                                           lightPos, lightWidth,
130                                           SK_ColorTRANSPARENT, spotColor, flags);
131             }
132 
133             SkColor spotGreyscale = SkColorSetARGB(spotAlpha * 255, 0, 0, 0);
134             SkShadowUtils::DrawShadow(canvas, path, zPlaneParams,
135                                       lightPos, lightWidth,
136                                       SK_ColorTRANSPARENT, spotGreyscale, flags);
137         } else {
138             SkColor color = paint.getColor();
139             SkColor baseAmbient = SkColorSetARGB(ambientAlpha*SkColorGetA(color),
140                                                  SkColorGetR(color), SkColorGetG(color),
141                                                  SkColorGetB(color));
142             SkColor baseSpot = SkColorSetARGB(spotAlpha*SkColorGetA(color),
143                                               SkColorGetR(color), SkColorGetG(color),
144                                               SkColorGetB(color));
145             SkColor tonalAmbient, tonalSpot;
146             SkShadowUtils::ComputeTonalColors(baseAmbient, baseSpot, &tonalAmbient, &tonalSpot);
147             SkShadowUtils::DrawShadow(canvas, path, zPlaneParams,
148                                       lightPos, lightWidth,
149                                       tonalAmbient, tonalSpot, flags);
150         }
151         if (fShowObject) {
152             canvas->drawPath(path, paint);
153         } else {
154             SkPaint strokePaint;
155 
156             strokePaint.setColor(paint.getColor());
157             strokePaint.setStyle(SkPaint::kStroke_Style);
158 
159             canvas->drawPath(path, strokePaint);
160         }
161     }
162 
onDrawContent(SkCanvas * canvas)163     void onDrawContent(SkCanvas* canvas) override {
164         const SkScalar kLightWidth = 600;
165         const SkScalar kAmbientAlpha = 0.03f;
166         const SkScalar kSpotAlpha = 0.25f;
167 
168         const SkScalar kZValues[10] = { 1, 2, 3, 4, 6, 8, 9, 12, 16, 24 };
169 
170         const SkColor kColors[30] = {
171             // purples
172             0xFF3A0072, 0xFF5D0099, 0xFF7F12B2, 0xFFA02AD1, 0xFFC245E5,
173             0xFFE95AF9, 0xFFFC79F0, 0xFFFDA6F0, 0xFFFFCCF8, 0xFFFFE1F9,
174             // oranges
175             0xFFEA3200, 0xFFFF4E00, 0xFFFF7300, 0xFFFF9100, 0xFFFFB000,
176             0xFFFFCE00, 0xFFFFE000, 0xFFFFF64D, 0xFFFFF98F, 0xFFFFFBCC,
177             // teals
178             0xFF004D51, 0xFF066266, 0xFF057F7F, 0xFF009999, 0xFF00B2B2,
179             0xFF15CCBE, 0xFF25E5CE, 0xFF2CFFE0, 0xFF80FFEA, 0xFFB3FFF0
180         };
181 
182         SkFont font;
183         SkPaint paint;
184         paint.setAntiAlias(true);
185         if (fDarkBackground) {
186             canvas->drawColor(0xFF111111);
187             paint.setColor(SK_ColorWHITE);
188         } else {
189             canvas->drawColor(0xFFEAEAEA);
190             paint.setColor(SK_ColorBLACK);
191         }
192         if (fTwoPassColor) {
193             canvas->drawString("Two pass", 10, 15, font, paint);
194         } else {
195             canvas->drawString("One pass", 10, 15, font, paint);
196         }
197 
198         SkPoint3 lightPos = { 75, -400, 600 };
199         SkPoint3 zPlaneParams = SkPoint3::Make(0, 0, kZValues[fZIndex]);
200         SkScalar yPos = 75;
201 
202         for (int row = 0; row < 3; ++row) {
203             lightPos.fX = 75;
204             SkScalar xPos = 75;
205             for (int col = 0; col < 10; ++col) {
206                 paint.setColor(kColors[10*row + col]);
207 
208                 canvas->save();
209                 canvas->translate(xPos, yPos);
210                 this->drawShadowedPath(canvas, fRectPath, zPlaneParams, paint, kAmbientAlpha,
211                                        lightPos, kLightWidth, kSpotAlpha);
212                 canvas->restore();
213 
214                 lightPos.fX += 120;
215                 xPos += 120;
216             }
217 
218             lightPos.fY += 200;
219             yPos += 200;
220         }
221     }
222 
223 private:
224     typedef Sample INHERITED;
225 };
226 
227 //////////////////////////////////////////////////////////////////////////////
228 
229 DEF_SAMPLE( return new ShadowColorView(); )
230