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      1 /*
      2  * Copyright (C) 2013 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 #include "core/rendering/ImageQualityController.h"
     33 
     34 #include "core/frame/FrameView.h"
     35 #include "core/frame/LocalFrame.h"
     36 #include "platform/graphics/GraphicsContext.h"
     37 
     38 namespace WebCore {
     39 
     40 static const double cLowQualityTimeThreshold = 0.500; // 500 ms
     41 
     42 static ImageQualityController* gImageQualityController = 0;
     43 
     44 ImageQualityController* ImageQualityController::imageQualityController()
     45 {
     46     if (!gImageQualityController)
     47         gImageQualityController = new ImageQualityController;
     48 
     49     return gImageQualityController;
     50 }
     51 
     52 void ImageQualityController::remove(RenderObject* renderer)
     53 {
     54     if (gImageQualityController) {
     55         gImageQualityController->objectDestroyed(renderer);
     56         if (gImageQualityController->isEmpty()) {
     57             delete gImageQualityController;
     58             gImageQualityController = 0;
     59         }
     60     }
     61 }
     62 
     63 InterpolationQuality ImageQualityController::chooseInterpolationQuality(GraphicsContext* context, RenderObject* object, Image* image, const void* layer, const LayoutSize& layoutSize)
     64 {
     65     if (InterpolationDefault == InterpolationLow)
     66         return InterpolationLow;
     67 
     68     if (shouldPaintAtLowQuality(context, object, image, layer, layoutSize))
     69         return InterpolationLow;
     70 
     71     // For images that are potentially animated we paint them at medium quality.
     72     if (image && image->maybeAnimated())
     73         return InterpolationMedium;
     74 
     75     return InterpolationDefault;
     76 }
     77 
     78 ImageQualityController::~ImageQualityController()
     79 {
     80     // This will catch users of ImageQualityController that forget to call cleanUp.
     81     ASSERT(!gImageQualityController || gImageQualityController->isEmpty());
     82 }
     83 
     84 ImageQualityController::ImageQualityController()
     85     : m_timer(this, &ImageQualityController::highQualityRepaintTimerFired)
     86     , m_animatedResizeIsActive(false)
     87     , m_liveResizeOptimizationIsActive(false)
     88 {
     89 }
     90 
     91 void ImageQualityController::removeLayer(RenderObject* object, LayerSizeMap* innerMap, const void* layer)
     92 {
     93     if (innerMap) {
     94         innerMap->remove(layer);
     95         if (innerMap->isEmpty())
     96             objectDestroyed(object);
     97     }
     98 }
     99 
    100 void ImageQualityController::set(RenderObject* object, LayerSizeMap* innerMap, const void* layer, const LayoutSize& size)
    101 {
    102     if (innerMap)
    103         innerMap->set(layer, size);
    104     else {
    105         LayerSizeMap newInnerMap;
    106         newInnerMap.set(layer, size);
    107         m_objectLayerSizeMap.set(object, newInnerMap);
    108     }
    109 }
    110 
    111 void ImageQualityController::objectDestroyed(RenderObject* object)
    112 {
    113     m_objectLayerSizeMap.remove(object);
    114     if (m_objectLayerSizeMap.isEmpty()) {
    115         m_animatedResizeIsActive = false;
    116         m_timer.stop();
    117     }
    118 }
    119 
    120 void ImageQualityController::highQualityRepaintTimerFired(Timer<ImageQualityController>*)
    121 {
    122     if (!m_animatedResizeIsActive && !m_liveResizeOptimizationIsActive)
    123         return;
    124     m_animatedResizeIsActive = false;
    125 
    126     for (ObjectLayerSizeMap::iterator it = m_objectLayerSizeMap.begin(); it != m_objectLayerSizeMap.end(); ++it) {
    127         if (LocalFrame* frame = it->key->document().frame()) {
    128             // If this renderer's containing FrameView is in live resize, punt the timer and hold back for now.
    129             if (frame->view() && frame->view()->inLiveResize()) {
    130                 restartTimer();
    131                 return;
    132             }
    133         }
    134         it->key->paintInvalidationForWholeRenderer();
    135     }
    136 
    137     m_liveResizeOptimizationIsActive = false;
    138 }
    139 
    140 void ImageQualityController::restartTimer()
    141 {
    142     m_timer.startOneShot(cLowQualityTimeThreshold, FROM_HERE);
    143 }
    144 
    145 bool ImageQualityController::shouldPaintAtLowQuality(GraphicsContext* context, RenderObject* object, Image* image, const void *layer, const LayoutSize& layoutSize)
    146 {
    147     // If the image is not a bitmap image, then none of this is relevant and we just paint at high
    148     // quality.
    149     if (!image || !image->isBitmapImage() || context->paintingDisabled())
    150         return false;
    151 
    152     if (object->style()->imageRendering() == ImageRenderingOptimizeContrast)
    153         return true;
    154 
    155     // Look ourselves up in the hashtables.
    156     ObjectLayerSizeMap::iterator i = m_objectLayerSizeMap.find(object);
    157     LayerSizeMap* innerMap = i != m_objectLayerSizeMap.end() ? &i->value : 0;
    158     LayoutSize oldSize;
    159     bool isFirstResize = true;
    160     if (innerMap) {
    161         LayerSizeMap::iterator j = innerMap->find(layer);
    162         if (j != innerMap->end()) {
    163             isFirstResize = false;
    164             oldSize = j->value;
    165         }
    166     }
    167 
    168     const AffineTransform& currentTransform = context->getCTM();
    169     bool contextIsScaled = !currentTransform.isIdentityOrTranslationOrFlipped();
    170 
    171     // Make sure to use the unzoomed image size, since if a full page zoom is in effect, the image
    172     // is actually being scaled.
    173     LayoutSize scaledImageSize = currentTransform.mapSize(image->size());
    174     LayoutSize scaledLayoutSize = currentTransform.mapSize(roundedIntSize(layoutSize));
    175 
    176     // If the containing FrameView is being resized, paint at low quality until resizing is finished.
    177     if (LocalFrame* frame = object->document().frame()) {
    178         bool frameViewIsCurrentlyInLiveResize = frame->view() && frame->view()->inLiveResize();
    179         if (frameViewIsCurrentlyInLiveResize) {
    180             set(object, innerMap, layer, scaledLayoutSize);
    181             restartTimer();
    182             m_liveResizeOptimizationIsActive = true;
    183             return true;
    184         }
    185         if (m_liveResizeOptimizationIsActive) {
    186             // Live resize has ended, paint in HQ and remove this object from the list.
    187             removeLayer(object, innerMap, layer);
    188             return false;
    189         }
    190     }
    191 
    192     // See crbug.com/382491. This test is insufficient to ensure that there is no scale
    193     // applied in the compositor, but it is probably adequate here. In the worst case we
    194     // draw at high quality when we need not.
    195     if (!contextIsScaled && scaledLayoutSize == scaledImageSize) {
    196         // There is no scale in effect. If we had a scale in effect before, we can just remove this object from the list.
    197         removeLayer(object, innerMap, layer);
    198         return false;
    199     }
    200 
    201     // If an animated resize is active, paint in low quality and kick the timer ahead.
    202     if (m_animatedResizeIsActive) {
    203         set(object, innerMap, layer, scaledLayoutSize);
    204         restartTimer();
    205         return true;
    206     }
    207     // If this is the first time resizing this image, or its size is the
    208     // same as the last resize, draw at high res, but record the paint
    209     // size and set the timer.
    210     if (isFirstResize || oldSize == scaledLayoutSize) {
    211         restartTimer();
    212         set(object, innerMap, layer, scaledLayoutSize);
    213         return false;
    214     }
    215     // If the timer is no longer active, draw at high quality and don't
    216     // set the timer.
    217     if (!m_timer.isActive()) {
    218         removeLayer(object, innerMap, layer);
    219         return false;
    220     }
    221     // This object has been resized to two different sizes while the timer
    222     // is active, so draw at low quality, set the flag for animated resizes and
    223     // the object to the list for high quality redraw.
    224     set(object, innerMap, layer, scaledLayoutSize);
    225     m_animatedResizeIsActive = true;
    226     restartTimer();
    227     return true;
    228 }
    229 
    230 } // namespace WebCore
    231