1 // Copyright 2020 Google LLC.
2 // Use of this source code is governed by a BSD-style license that can be found in the LICENSE file.
3 #include "tools/fiddle/examples.h"
4 REG_FIDDLE(picture_shader, 256, 256, false, 5) {
draw_centered(const char * s,const SkFont & font,SkColor color,SkPoint xy,SkCanvas * c)5 static void draw_centered(
6 const char* s, const SkFont& font, SkColor color, SkPoint xy, SkCanvas* c) {
7 sk_sp<SkTextBlob> b = SkTextBlob::MakeFromString(s, font);
8 xy -= SkPoint{b->bounds().centerX(), b->bounds().centerY()};
9 SkPaint p;
10 p.setColor(color);
11 c->drawTextBlob(b.get(), xy.x(), xy.y(), p);
12 }
13
from_polar_deg(float r,float d)14 SkPoint from_polar_deg(float r, float d) {
15 float a = d * 0.017453292519943295;
16 return {r * cosf(a), r * sinf(a)};
17 }
18
draw_wheel(SkCanvas * c)19 void draw_wheel(SkCanvas* c) {
20 const SkScalar scale = 512;
21 SkAutoCanvasRestore autoCanvasRestore(c, true);
22 c->translate(0.5f * scale, 0.5f * scale);
23 SkPaint p;
24 p.setAntiAlias(true);
25 p.setColor(SK_ColorWHITE);
26 c->drawCircle(0.0f, 0.0f, scale * 0.475f, p);
27
28 const SkColor sweep_colors[] = {SK_ColorRED, SK_ColorYELLOW, SK_ColorGREEN, SK_ColorCYAN,
29 SK_ColorBLUE, SK_ColorMAGENTA, SK_ColorRED};
30 SkMatrix rot;
31 rot.setRotate(90.0f);
32 p.setShader(SkGradientShader::MakeSweep(0, 0, sweep_colors, NULL,
33 SK_ARRAY_COUNT(sweep_colors), 0, &rot));
34 p.setStrokeWidth(0.05f * scale);
35 p.setStyle(SkPaint::kStroke_Style);
36 c->drawCircle(0.0f, 0.0f, 0.475f * scale, p);
37
38 SkFont f(nullptr, 0.28125f * scale);
39 draw_centered("K", f, SK_ColorBLACK, {0.0f, 0.0f}, c);
40 draw_centered("R", f, SK_ColorRED, from_polar_deg(0.3f * scale, 90), c);
41 draw_centered("G", f, SK_ColorGREEN, from_polar_deg(0.3f * scale, 210), c);
42 draw_centered("B", f, SK_ColorBLUE, from_polar_deg(0.3f * scale, 330), c);
43 draw_centered("C", f, SK_ColorCYAN, from_polar_deg(0.3f * scale, 270), c);
44 draw_centered("M", f, SK_ColorMAGENTA, from_polar_deg(0.3f * scale, 30), c);
45 draw_centered("Y", f, SK_ColorYELLOW, from_polar_deg(0.3f * scale, 150), c);
46 }
47
draw(SkCanvas * canvas)48 void draw(SkCanvas* canvas) {
49 canvas->clear(SK_ColorWHITE);
50 SkMatrix matrix;
51 matrix.setScale(0.25f, 0.25f);
52 matrix.preRotate(30.0f);
53 SkPaint paint;
54 SkPictureRecorder rec;
55 draw_wheel(rec.beginRecording(512, 512));
56 paint.setShader(rec.finishRecordingAsPicture()->makeShader(
57 SkTileMode::kRepeat, SkTileMode::kRepeat, SkFilterMode::kNearest, &matrix, nullptr));
58 canvas->drawPaint(paint);
59 }
60 } // END FIDDLE
61