samplecode/SampleSubpixelTranslate.cpp

   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
  22 class SubpixelTranslateView : public SampleView {
  23 public:
  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           SkDELETE(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
  47 protected:
  48     SkBitmap fBM;
  49     SkScalar fSize;
  50     float fHorizontalVelocity, fVerticalVelocity;
  51
  52     SkPoint fCurPos;
  53
  54     // overrides from SkEventSink
  55     bool onQuery(SkEvent* evt) SK_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) SK_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
 115 private:
 116     typedef SampleView INHERITED;
 117 };
 118
 119 //////////////////////////////////////////////////////////////////////////////
 120
 121 static SkView* MyFactory() { return new SubpixelTranslateView("mandrill_256.png", .05f, .05f); }
 122 static SkViewRegister reg(MyFactory);