src/third_party/skia/src/effects/SkResizeImageFilter.cpp

   1 /*
   2  * Copyright 2013 The Android Open Source Project
   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 "SkResizeImageFilter.h"
   9 #include "SkBitmap.h"
  10 #include "SkCanvas.h"
  11 #include "SkDevice.h"
  12 #include "SkColorPriv.h"
  13 #include "SkReadBuffer.h"
  14 #include "SkWriteBuffer.h"
  15 #include "SkMatrix.h"
  16 #include "SkRect.h"
  17
  18 SkResizeImageFilter::SkResizeImageFilter(SkScalar sx, SkScalar sy, SkPaint::FilterLevel filterLevel,
  19                                          SkImageFilter* input)
  20   : INHERITED(input),
  21     fSx(sx),
  22     fSy(sy),
  23     fFilterLevel(filterLevel) {
  24 }
  25
  26 SkResizeImageFilter::SkResizeImageFilter(SkReadBuffer& buffer)
  27   : INHERITED(1, buffer) {
  28     fSx = buffer.readScalar();
  29     fSy = buffer.readScalar();
  30     fFilterLevel = static_cast<SkPaint::FilterLevel>(buffer.readInt());
  31 }
  32
  33 void SkResizeImageFilter::flatten(SkWriteBuffer& buffer) const {
  34     this->INHERITED::flatten(buffer);
  35     buffer.writeScalar(fSx);
  36     buffer.writeScalar(fSy);
  37     buffer.writeInt(fFilterLevel);
  38 }
  39
  40 SkResizeImageFilter::~SkResizeImageFilter() {
  41 }
  42
  43 bool SkResizeImageFilter::onFilterImage(Proxy* proxy,
  44                                          const SkBitmap& source,
  45                                          const Context& ctx,
  46                                          SkBitmap* result,
  47                                          SkIPoint* offset) const {
  48     SkBitmap src = source;
  49     SkIPoint srcOffset = SkIPoint::Make(0, 0);
  50     if (getInput(0) && !getInput(0)->filterImage(proxy, source, ctx, &src, &srcOffset)) {
  51         return false;
  52     }
  53
  54     SkRect dstRect;
  55     SkIRect srcBounds, dstBounds;
  56     src.getBounds(&srcBounds);
  57     srcBounds.offset(srcOffset);
  58     SkRect srcRect = SkRect::Make(srcBounds);
  59     SkMatrix matrix;
  60     if (!ctx.ctm().invert(&matrix)) {
  61         return false;
  62     }
  63     matrix.postScale(fSx, fSy);
  64     matrix.postConcat(ctx.ctm());
  65     matrix.mapRect(&dstRect, srcRect);
  66     dstRect.roundOut(&dstBounds);
  67
  68     SkAutoTUnref<SkBaseDevice> device(proxy->createDevice(dstBounds.width(), dstBounds.height()));
  69     if (NULL == device.get()) {
  70         return false;
  71     }
  72
  73     SkCanvas canvas(device.get());
  74     canvas.scale(fSx, fSy);
  75     SkPaint paint;
  76
  77     paint.setXfermodeMode(SkXfermode::kSrc_Mode);
  78     paint.setFilterLevel(fFilterLevel);
  79     canvas.drawBitmap(src, 0, 0, &paint);
  80
  81     *result = device.get()->accessBitmap(false);
  82     offset->fX = dstBounds.fLeft;
  83     offset->fY = dstBounds.fTop;
  84     return true;
  85 }
  86
  87 void SkResizeImageFilter::computeFastBounds(const SkRect& src, SkRect* dst) const {
  88     SkRect bounds = src;
  89     if (getInput(0)) {
  90         getInput(0)->computeFastBounds(src, &bounds);
  91     }
  92     dst->setXYWH(bounds.x(), bounds.y(), bounds.width() * fSx, bounds.height() * fSy);
  93 }
  94
  95 bool SkResizeImageFilter::onFilterBounds(const SkIRect& src, const SkMatrix& ctm,
  96                                          SkIRect* dst) const {
  97     SkMatrix matrix;
  98     if (!ctm.invert(&matrix)) {
  99         return false;
 100     }
 101     matrix.postScale(SkScalarInvert(fSx), SkScalarInvert(fSy));
 102     matrix.postConcat(ctm);
 103     SkRect floatBounds;
 104     matrix.mapRect(&floatBounds, SkRect::Make(src));
 105     SkIRect bounds;
 106     floatBounds.roundOut(&bounds);
 107     if (getInput(0) && !getInput(0)->filterBounds(bounds, ctm, &bounds)) {
 108         return false;
 109     }
 110
 111     *dst = bounds;
 112     return true;
 113 }