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      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 = nullptr;
     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 
     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) 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(nullptr);
    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);
    123