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 "include/core/SkCanvas.h"
9 #include "include/core/SkColorFilter.h"
10 #include "include/core/SkColorPriv.h"
11 #include "include/core/SkFont.h"
12 #include "include/core/SkImage.h"
13 #include "include/core/SkTime.h"
14 #include "include/core/SkTypeface.h"
15 #include "include/utils/SkRandom.h"
16 #include "samplecode/Sample.h"
17 #include "src/utils/SkUTF.h"
18
19 #if SK_SUPPORT_GPU
20 #include "include/gpu/GrDirectContext.h"
21 #include "src/gpu/GrDirectContextPriv.h"
22 #endif
23
24 SkRandom gRand;
25
DrawTheText(SkCanvas * canvas,const char text[],size_t length,SkScalar x,SkScalar y,const SkFont & font,const SkPaint & paint)26 static void DrawTheText(SkCanvas* canvas, const char text[], size_t length, SkScalar x, SkScalar y,
27 const SkFont& font, const SkPaint& paint) {
28 SkFont f(font);
29 f.setSubpixel(true);
30 canvas->drawSimpleText(text, length, SkTextEncoding::kUTF8, x, y, f, paint);
31 }
32
33 // This sample demonstrates the cache behavior of bitmap vs. distance field text
34 // It renders variously sized text with an animated scale and rotation.
35 // Specifically one should:
36 // use 'D' to toggle between bitmap and distance field fonts
37 // use '2' to toggle between scaling the image by 2x
38 // -- this feature boosts the rendering out of the small point-size
39 // SDF-text special case (which falls back to bitmap fonts for small points)
40
41 class AnimatedTextView : public Sample {
42 float fScale = 1;
43 float fScaleInc = 0.1f;
44 float fRotation = 0;
45 int fSizeScale = 1;
46
name()47 SkString name() override { return SkString("AnimatedText"); }
48
onChar(SkUnichar uni)49 bool onChar(SkUnichar uni) override {
50 if ('2' == uni) {
51 if (fSizeScale == 2) {
52 fSizeScale = 1;
53 } else {
54 fSizeScale = 2;
55 }
56 return true;
57 }
58 return false;
59 }
60
onDrawContent(SkCanvas * canvas)61 void onDrawContent(SkCanvas* canvas) override {
62 SkFont font(SkTypeface::MakeFromFile("/skimages/samplefont.ttf"));
63
64 SkPaint paint;
65 paint.setAntiAlias(true);
66
67 canvas->save();
68
69 #if SK_SUPPORT_GPU
70 auto direct = GrAsDirectContext(canvas->recordingContext());
71 if (direct) {
72 SkSamplingOptions sampling(SkFilterMode::kLinear, SkMipmapMode::kNearest);
73 sk_sp<SkImage> image = direct->priv().testingOnly_getFontAtlasImage(
74 GrMaskFormat::kA8_GrMaskFormat);
75 const SkRect rect = SkRect::MakeXYWH(512.0f, 10.0f, 512.0f, 512.0f);
76 canvas->drawImageRect(image.get(), rect, rect, sampling, &paint,
77 SkCanvas::kFast_SrcRectConstraint);
78 }
79 #endif
80 canvas->translate(180, 180);
81 canvas->rotate(fRotation);
82 canvas->scale(fScale, fScale);
83 canvas->translate(-180, -180);
84
85 const char* text = "Hamburgefons";
86 size_t length = strlen(text);
87
88 SkScalar y = SkIntToScalar(0);
89 for (int i = 12; i <= 26; i++) {
90 font.setSize(SkIntToScalar(i*fSizeScale));
91 y += font.getSpacing();
92 DrawTheText(canvas, text, length, SkIntToScalar(110), y, font, paint);
93 }
94 canvas->restore();
95
96 font.setSize(16);
97 }
98
onAnimate(double nanos)99 bool onAnimate(double nanos) override {
100 // TODO: use nanos
101 // We add noise to the scale and rotation animations to
102 // keep the font atlas from falling into a steady state
103 fRotation += (1.0f + gRand.nextRangeF(-0.1f, 0.1f));
104 fScale += (fScaleInc + gRand.nextRangeF(-0.025f, 0.025f));
105 if (fScale >= 2.0f) {
106 fScaleInc = -0.1f;
107 } else if (fScale <= 1.0f) {
108 fScaleInc = 0.1f;
109 }
110 return true;
111 }
112 };
113
114 DEF_SAMPLE( return new AnimatedTextView(); )
115