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
24SkRandom gRand;
25
26static 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
41class AnimatedTextView : public Sample {
42    float fScale = 1;
43    float fScaleInc = 0.1f;
44    float fRotation = 0;
45    int   fSizeScale = 1;
46
47    SkString name() override { return SkString("AnimatedText"); }
48
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
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
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
114DEF_SAMPLE( return new AnimatedTextView(); )
115