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      1 /*
      2  * Copyright (c) 2008, Google Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions are
      6  * met:
      7  *
      8  *     * Redistributions of source code must retain the above copyright
      9  * notice, this list of conditions and the following disclaimer.
     10  *     * Redistributions in binary form must reproduce the above
     11  * copyright notice, this list of conditions and the following disclaimer
     12  * in the documentation and/or other materials provided with the
     13  * distribution.
     14  *     * Neither the name of Google Inc. nor the names of its
     15  * contributors may be used to endorse or promote products derived from
     16  * this software without specific prior written permission.
     17  *
     18  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
     19  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
     20  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
     21  * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
     22  * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
     23  * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
     24  * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
     25  * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
     26  * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     27  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     28  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     29  */
     30 
     31 #include "config.h"
     32 
     33 #if !PLATFORM(ANDROID)
     34 #include "skia/ext/image_operations.h"
     35 #endif
     36 
     37 #include "NativeImageSkia.h"
     38 #include "SharedGraphicsContext3D.h"
     39 #include "SkiaUtils.h"
     40 
     41 namespace WebCore {
     42 
     43 NativeImageSkia::NativeImageSkia()
     44     : m_isDataComplete(false),
     45       m_lastRequestSize(0, 0),
     46       m_resizeRequests(0)
     47 {
     48 }
     49 
     50 NativeImageSkia::NativeImageSkia(const SkBitmap& other)
     51     : SkBitmap(other),
     52       m_isDataComplete(false),
     53       m_lastRequestSize(0, 0),
     54       m_resizeRequests(0)
     55 {
     56 }
     57 
     58 
     59 NativeImageSkia::~NativeImageSkia()
     60 {
     61 #if PLATFORM(ANDROID)
     62     // SharedGraphicsContext3D::removeTexturesFor() takes a NativeImagePtr. On
     63     // Chromium, this is NativeImageSkia, which inherits from SkBitmap. On
     64     // Android, NativeImagePtr is a SkBitmapRef, which is a wrapper around
     65     // SkBitmap. Failing to call removeTexturesFor() probably causes a leak.
     66     // TODO: Fix this. See http://b/3047425
     67 #else
     68     SharedGraphicsContext3D::removeTexturesFor(this);
     69 #endif
     70 }
     71 
     72 int NativeImageSkia::decodedSize() const
     73 {
     74     return getSize() + m_resizedImage.getSize();
     75 }
     76 
     77 bool NativeImageSkia::hasResizedBitmap(int w, int h) const
     78 {
     79     if (m_lastRequestSize.width() == w && m_lastRequestSize.height() == h)
     80         m_resizeRequests++;
     81     else {
     82         m_lastRequestSize = IntSize(w, h);
     83         m_resizeRequests = 0;
     84     }
     85 
     86     return m_resizedImage.width() == w && m_resizedImage.height() == h;
     87 }
     88 
     89 // FIXME: don't cache when image is in-progress.
     90 
     91 SkBitmap NativeImageSkia::resizedBitmap(int w, int h) const
     92 {
     93 #if !PLATFORM(ANDROID)
     94     if (m_resizedImage.width() != w || m_resizedImage.height() != h)
     95         m_resizedImage = skia::ImageOperations::Resize(*this, skia::ImageOperations::RESIZE_LANCZOS3, w, h);
     96 #endif
     97 
     98     return m_resizedImage;
     99 }
    100 
    101 bool NativeImageSkia::shouldCacheResampling(int destWidth,
    102                                             int destHeight,
    103                                             int destSubsetWidth,
    104                                             int destSubsetHeight) const
    105 {
    106     // We can not cache incomplete frames. This might be a good optimization in
    107     // the future, were we know how much of the frame has been decoded, so when
    108     // we incrementally draw more of the image, we only have to resample the
    109     // parts that are changed.
    110     if (!m_isDataComplete)
    111         return false;
    112 
    113     // If the destination bitmap is small, we'll always allow caching, since
    114     // there is not very much penalty for computing it and it may come in handy.
    115     static const int kSmallBitmapSize = 4096;
    116     if (destWidth * destHeight <= kSmallBitmapSize)
    117         return true;
    118 
    119     // If "too many" requests have been made for this bitmap, we assume that
    120     // many more will be made as well, and we'll go ahead and cache it.
    121     static const int kManyRequestThreshold = 4;
    122     if (m_lastRequestSize.width() == destWidth &&
    123         m_lastRequestSize.height() == destHeight) {
    124         if (m_resizeRequests >= kManyRequestThreshold)
    125             return true;
    126     } else {
    127         // When a different size is being requested, count this as a query
    128         // (hasResizedBitmap) and reset the counter.
    129         m_lastRequestSize = IntSize(destWidth, destHeight);
    130         m_resizeRequests = 0;
    131     }
    132 
    133     // Otherwise, use the heuristic that if more than 1/4 of the image is
    134     // requested, it's worth caching.
    135     int destSize = destWidth * destHeight;
    136     int destSubsetSize = destSubsetWidth * destSubsetHeight;
    137     return destSize / 4 < destSubsetSize;
    138 }
    139 
    140 } // namespace WebCore
    141