1 /*
2 * Copyright 2016 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 "SkDashPathEffect.h"
11 #include "SkGradientShader.h"
12 #include "SkMaskFilter.h"
13 #include "SkPaint.h"
14 #include "SkPath.h"
15 #include "SkPoint3.h"
16
17 constexpr int kNumColumns = 6;
18 constexpr int kNumRows = 8;
19 constexpr int kRadius = 40; // radius of the snowflake
20 constexpr int kPad = 5; // padding on both sides of the snowflake
21 constexpr int kNumSpokes = 6;
22 constexpr SkScalar kStrokeWidth = 5.0f;
23
draw_fins(SkCanvas * canvas,const SkPoint & offset,float angle,const SkPaint & paint)24 static void draw_fins(SkCanvas* canvas, const SkPoint& offset, float angle, const SkPaint& paint) {
25 SkScalar cos, sin;
26
27 // first fin
28 sin = SkScalarSinCos(angle + (SK_ScalarPI/4), &cos);
29 sin *= kRadius / 2.0f;
30 cos *= kRadius / 2.0f;
31
32 SkPath p;
33 p.moveTo(offset.fX, offset.fY);
34 p.lineTo(offset.fX + cos, offset.fY + sin);
35 canvas->drawPath(p, paint);
36
37 // second fin
38 sin = SkScalarSinCos(angle - (SK_ScalarPI/4), &cos);
39 sin *= kRadius / 2.0f;
40 cos *= kRadius / 2.0f;
41
42 p.reset();
43 p.moveTo(offset.fX, offset.fY);
44 p.lineTo(offset.fX + cos, offset.fY + sin);
45 canvas->drawPath(p, paint);
46 }
47
48 // draw a snowflake centered at the origin
draw_snowflake(SkCanvas * canvas,const SkPaint & paint)49 static void draw_snowflake(SkCanvas* canvas, const SkPaint& paint) {
50
51 canvas->clipRect(SkRect::MakeLTRB(-kRadius-kPad, -kRadius-kPad, kRadius+kPad, kRadius+kPad));
52
53 SkScalar sin, cos, angle = 0.0f;
54 for (int i = 0; i < kNumSpokes/2; ++i, angle += SK_ScalarPI/(kNumSpokes/2)) {
55 sin = SkScalarSinCos(angle, &cos);
56 sin *= kRadius;
57 cos *= kRadius;
58
59 // main spoke
60 SkPath p;
61 p.moveTo(-cos, -sin);
62 p.lineTo(cos, sin);
63 canvas->drawPath(p, paint);
64
65 // fins on positive side
66 const SkPoint posOffset = SkPoint::Make(0.5f * cos, 0.5f * sin);
67 draw_fins(canvas, posOffset, angle, paint);
68
69 // fins on negative side
70 const SkPoint negOffset = SkPoint::Make(-0.5f * cos, -0.5f * sin);
71 draw_fins(canvas, negOffset, angle+SK_ScalarPI, paint);
72 }
73 }
74
draw_row(SkCanvas * canvas,const SkPaint & paint,const SkMatrix & localMatrix)75 static void draw_row(SkCanvas* canvas, const SkPaint& paint, const SkMatrix& localMatrix) {
76 canvas->translate(kRadius+kPad, 0.0f);
77
78 for (auto cap : { SkPaint::kButt_Cap, SkPaint::kRound_Cap, SkPaint::kSquare_Cap }) {
79 for (auto isAA : { true, false }) {
80 SkPaint tmp(paint);
81 tmp.setStrokeWidth(kStrokeWidth);
82 tmp.setStyle(SkPaint::kStroke_Style);
83 tmp.setStrokeCap(cap);
84 tmp.setAntiAlias(isAA);
85
86 int saveCount = canvas->save();
87 canvas->concat(localMatrix);
88 draw_snowflake(canvas, tmp);
89 canvas->restoreToCount(saveCount);
90
91 canvas->translate(2*(kRadius+kPad), 0.0f);
92 }
93 }
94 }
95
96 namespace skiagm {
97
98 // This GM exercises the special case of a stroked lines.
99 // Various shaders are applied to ensure the coordinate spaces work out right.
100 class StrokedLinesGM : public GM {
101 public:
StrokedLinesGM()102 StrokedLinesGM() {
103 this->setBGColor(sk_tool_utils::color_to_565(0xFF1A65D7));
104 }
105
106 protected:
onShortName()107 SkString onShortName() override {
108 return SkString("strokedlines");
109 }
110
onISize()111 SkISize onISize() override {
112 return SkISize::Make(kNumColumns * (2*kRadius+2*kPad), kNumRows * (2*kRadius+2*kPad));
113 }
114
onOnceBeforeDraw()115 void onOnceBeforeDraw() override {
116 // paints
117 {
118 // basic white
119 SkPaint p;
120 p.setColor(SK_ColorWHITE);
121 fPaints.push_back(p);
122 }
123 {
124 // gradient
125 SkColor colors[] = { SK_ColorRED, SK_ColorGREEN };
126 SkPoint pts[] = { {-kRadius-kPad, -kRadius-kPad }, { kRadius+kPad, kRadius+kPad } };
127
128 SkPaint p;
129 p.setShader(SkGradientShader::MakeLinear(pts, colors, nullptr, 2,
130 SkShader::kClamp_TileMode, 0, nullptr));
131
132 fPaints.push_back(p);
133 }
134 {
135 // dashing
136 SkScalar intervals[] = { kStrokeWidth, kStrokeWidth };
137 int intervalCount = (int) SK_ARRAY_COUNT(intervals);
138 SkPaint p;
139 p.setColor(SK_ColorWHITE);
140 p.setPathEffect(SkDashPathEffect::Make(intervals, intervalCount, kStrokeWidth));
141
142 fPaints.push_back(p);
143 }
144 {
145 // Bitmap shader
146 SkBitmap bm;
147 bm.allocN32Pixels(2, 2);
148 *bm.getAddr32(0, 0) = *bm.getAddr32(1, 1) = 0xFFFFFFFF;
149 *bm.getAddr32(1, 0) = *bm.getAddr32(0, 1) = 0x0;
150
151 SkMatrix m;
152 m.setRotate(12.0f);
153 m.preScale(3.0f, 3.0f);
154
155 SkPaint p;
156 p.setShader(SkShader::MakeBitmapShader(bm,
157 SkShader::kRepeat_TileMode,
158 SkShader::kRepeat_TileMode,
159 &m));
160 fPaints.push_back(p);
161 }
162 {
163 // blur
164 SkPaint p;
165 p.setColor(SK_ColorWHITE);
166 p.setMaskFilter(SkMaskFilter::MakeBlur(kOuter_SkBlurStyle, 3.0f));
167 fPaints.push_back(p);
168 }
169
170 // matrices
171 {
172 // rotation
173 SkMatrix m;
174 m.setRotate(12.0f);
175
176 fMatrices.push_back(m);
177 }
178 {
179 // skew
180 SkMatrix m;
181 m.setSkew(0.3f, 0.5f);
182
183 fMatrices.push_back(m);
184 }
185 {
186 // perspective
187 SkMatrix m;
188 m.reset();
189 m.setPerspX(-SK_Scalar1 / 300);
190 m.setPerspY(SK_Scalar1 / 300);
191
192 fMatrices.push_back(m);
193 }
194
195 SkASSERT(kNumRows == fPaints.count() + fMatrices.count());
196 }
197
onDraw(SkCanvas * canvas)198 void onDraw(SkCanvas* canvas) override {
199 canvas->translate(0, kRadius+kPad);
200
201 for (int i = 0; i < fPaints.count(); ++i) {
202 int saveCount = canvas->save();
203 draw_row(canvas, fPaints[i], SkMatrix::I());
204 canvas->restoreToCount(saveCount);
205
206 canvas->translate(0, 2*(kRadius+kPad));
207 }
208
209 for (int i = 0; i < fMatrices.count(); ++i) {
210 int saveCount = canvas->save();
211 draw_row(canvas, fPaints[0], fMatrices[i]);
212 canvas->restoreToCount(saveCount);
213
214 canvas->translate(0, 2*(kRadius+kPad));
215 }
216 }
217
218 private:
219 SkTArray<SkPaint> fPaints;
220 SkTArray<SkMatrix> fMatrices;
221
222 typedef GM INHERITED;
223 };
224
225 //////////////////////////////////////////////////////////////////////////////
226
227 DEF_GM(return new StrokedLinesGM;)
228 }
229