SampleSubpixelTranslate.cpp revision 385fe4d4b62d7d1dd76116dd570df3290a2f487b 
1/*
2 * Copyright 2014 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
10#include "Resources.h"
11#include "SampleCode.h"
12#include "SkBlurMaskFilter.h"
13#include "SkCanvas.h"
14#include "SkColorPriv.h"
15#include "SkImageDecoder.h"
16#include "SkRandom.h"
17#include "SkStream.h"
18
19// Intended to exercise pixel snapping observed with scaled images (and
20// with non-scaled images, but for a different reason):  Bug 1145
21
22class SubpixelTranslateView : public SampleView {
23public:
24    SubpixelTranslateView(const char imageFilename[],
25                          float horizontalVelocity,
26                          float verticalVelocity)
27      : fHorizontalVelocity(horizontalVelocity),
28        fVerticalVelocity(verticalVelocity) {
29      SkString resourcePath = GetResourcePath(imageFilename);
30      SkImageDecoder* codec = NULL;
31      SkFILEStream stream(resourcePath.c_str());
32      if (stream.isValid()) {
33          codec = SkImageDecoder::Factory(&stream);
34      }
35      if (codec) {
36          stream.rewind();
37          codec->decode(&stream, &fBM, kN32_SkColorType, SkImageDecoder::kDecodePixels_Mode);
38          delete codec;
39      } else {
40          fBM.allocN32Pixels(1, 1);
41          *(fBM.getAddr32(0,0)) = 0xFF0000FF; // red == bad
42      }
43      fCurPos = SkPoint::Make(0,0);
44      fSize = 200;
45    }
46
47protected:
48    SkBitmap fBM;
49    SkScalar fSize;
50    float fHorizontalVelocity, fVerticalVelocity;
51
52    SkPoint fCurPos;
53
54    // overrides from SkEventSink
55    bool onQuery(SkEvent* evt) override {
56        if (SampleCode::TitleQ(*evt)) {
57            SampleCode::TitleR(evt, "SubpixelTranslate");
58            return true;
59        }
60        return this->INHERITED::onQuery(evt);
61    }
62
63    void onDrawContent(SkCanvas* canvas) override {
64
65        static const SkFilterQuality gQualitys[] = {
66            kNone_SkFilterQuality,
67            kLow_SkFilterQuality,
68            kMedium_SkFilterQuality,
69            kHigh_SkFilterQuality
70        };
71
72        SkPaint paint;
73        paint.setTextSize(48);
74        paint.setSubpixelText(true);
75
76        paint.setAntiAlias(true);
77        for (size_t i = 0; i < SK_ARRAY_COUNT(gQualitys); ++i) {
78            paint.setFilterQuality(gQualitys[i]);
79            SkRect r = SkRect::MakeXYWH( fCurPos.fX + i * (fSize + 10), fCurPos.fY, fSize, fSize );
80            canvas->drawBitmapRect( fBM, r, &paint );
81        }
82
83        canvas->drawText( "AA Scaled", strlen("AA Scaled"), fCurPos.fX + SK_ARRAY_COUNT(gQualitys) * (fSize + 10), fCurPos.fY + fSize/2, paint );
84
85        paint.setAntiAlias(false);
86        for (size_t i = 0; i < SK_ARRAY_COUNT(gQualitys); ++i) {
87            paint.setFilterQuality(gQualitys[i]);
88            SkRect r = SkRect::MakeXYWH( fCurPos.fX + i * (fSize + 10), fCurPos.fY + fSize + 10, fSize, fSize );
89            canvas->drawBitmapRect( fBM, r, &paint );
90        }
91        canvas->drawText( "Scaled", strlen("Scaled"), fCurPos.fX + SK_ARRAY_COUNT(gQualitys) * (fSize + 10), fCurPos.fY + fSize + 10 + fSize/2, paint );
92
93        paint.setAntiAlias(true);
94        for (size_t i = 0; i < SK_ARRAY_COUNT(gQualitys); ++i) {
95            paint.setFilterQuality(gQualitys[i]);
96            canvas->drawBitmap( fBM, fCurPos.fX + i * (fBM.width() + 10), fCurPos.fY + 2*(fSize + 10), &paint );
97        }
98
99        canvas->drawText( "AA No Scale", strlen("AA No Scale"), fCurPos.fX + SK_ARRAY_COUNT(gQualitys) * (fBM.width() + 10), fCurPos.fY + 2*(fSize + 10) + fSize/2, paint );
100
101        paint.setAntiAlias(false);
102        for (size_t i = 0; i < SK_ARRAY_COUNT(gQualitys); ++i) {
103            paint.setFilterQuality(gQualitys[i]);
104            canvas->drawBitmap( fBM, fCurPos.fX + i * (fBM.width() + 10), fCurPos.fY + 2*(fSize + 10) + fBM.height() + 10, &paint );
105        }
106
107        canvas->drawText( "No Scale", strlen("No Scale"), fCurPos.fX + SK_ARRAY_COUNT(gQualitys) * (fBM.width() + 10), fCurPos.fY + 2*(fSize + 10) + fBM.height() + 10 + fSize/2, paint );
108
109
110        fCurPos.fX += fHorizontalVelocity;
111        fCurPos.fY += fVerticalVelocity;
112        this->inval(NULL);
113    }
114
115private:
116    typedef SampleView INHERITED;
117};
118
119//////////////////////////////////////////////////////////////////////////////
120
121static SkView* MyFactory() { return new SubpixelTranslateView("mandrill_256.png", .05f, .05f); }
122static SkViewRegister reg(MyFactory);
123