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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 blink {
     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 bool ImageQualityController::has(RenderObject* renderer)
     64 {
     65     return gImageQualityController && gImageQualityController->m_objectLayerSizeMap.contains(renderer);
     66 }
     67 
     68 InterpolationQuality ImageQualityController::chooseInterpolationQuality(GraphicsContext* context, RenderObject* object, Image* image, const void* layer, const LayoutSize& layoutSize)
     69 {
     70     if (object->style()->imageRendering() == ImageRenderingPixelated
     71         && image
     72         && (layoutSize.width() > image->width() || layoutSize.height() > image->height() || layoutSize == image->size())) {
     73         return InterpolationNone;
     74     }
     75 
     76     if (InterpolationDefault == InterpolationLow)
     77         return InterpolationLow;
     78 
     79     if (shouldPaintAtLowQuality(context, object, image, layer, layoutSize))
     80         return InterpolationLow;
     81 
     82     // For images that are potentially animated we paint them at medium quality.
     83     if (image && image->maybeAnimated())
     84         return InterpolationMedium;
     85 
     86     return InterpolationDefault;
     87 }
     88 
     89 ImageQualityController::~ImageQualityController()
     90 {
     91     // This will catch users of ImageQualityController that forget to call cleanUp.
     92     ASSERT(!gImageQualityController || gImageQualityController->isEmpty());
     93 }
     94 
     95 ImageQualityController::ImageQualityController()
     96     : m_timer(this, &ImageQualityController::highQualityRepaintTimerFired)
     97     , m_animatedResizeIsActive(false)
     98     , m_liveResizeOptimizationIsActive(false)
     99 {
    100 }
    101 
    102 void ImageQualityController::removeLayer(RenderObject* object, LayerSizeMap* innerMap, const void* layer)
    103 {
    104     if (innerMap) {
    105         innerMap->remove(layer);
    106         if (innerMap->isEmpty())
    107             objectDestroyed(object);
    108     }
    109 }
    110 
    111 void ImageQualityController::set(RenderObject* object, LayerSizeMap* innerMap, const void* layer, const LayoutSize& size)
    112 {
    113     if (innerMap)
    114         innerMap->set(layer, size);
    115     else {
    116         LayerSizeMap newInnerMap;
    117         newInnerMap.set(layer, size);
    118         m_objectLayerSizeMap.set(object, newInnerMap);
    119     }
    120 }
    121 
    122 void ImageQualityController::objectDestroyed(RenderObject* object)
    123 {
    124     m_objectLayerSizeMap.remove(object);
    125     if (m_objectLayerSizeMap.isEmpty()) {
    126         m_animatedResizeIsActive = false;
    127         m_timer.stop();
    128     }
    129 }
    130 
    131 void ImageQualityController::highQualityRepaintTimerFired(Timer<ImageQualityController>*)
    132 {
    133     if (!m_animatedResizeIsActive && !m_liveResizeOptimizationIsActive)
    134         return;
    135     m_animatedResizeIsActive = false;
    136 
    137     for (ObjectLayerSizeMap::iterator it = m_objectLayerSizeMap.begin(); it != m_objectLayerSizeMap.end(); ++it) {
    138         if (LocalFrame* frame = it->key->document().frame()) {
    139             // If this renderer's containing FrameView is in live resize, punt the timer and hold back for now.
    140             if (frame->view() && frame->view()->inLiveResize()) {
    141                 restartTimer();
    142                 return;
    143             }
    144         }
    145         it->key->setShouldDoFullPaintInvalidation(true);
    146     }
    147 
    148     m_liveResizeOptimizationIsActive = false;
    149 }
    150 
    151 void ImageQualityController::restartTimer()
    152 {
    153     m_timer.startOneShot(cLowQualityTimeThreshold, FROM_HERE);
    154 }
    155 
    156 bool ImageQualityController::shouldPaintAtLowQuality(GraphicsContext* context, RenderObject* object, Image* image, const void *layer, const LayoutSize& layoutSize)
    157 {
    158     // If the image is not a bitmap image, then none of this is relevant and we just paint at high
    159     // quality.
    160     if (!image || !image->isBitmapImage())
    161         return false;
    162 
    163     if (object->style()->imageRendering() == ImageRenderingOptimizeContrast)
    164         return true;
    165 
    166     // Look ourselves up in the hashtables.
    167     ObjectLayerSizeMap::iterator i = m_objectLayerSizeMap.find(object);
    168     LayerSizeMap* innerMap = i != m_objectLayerSizeMap.end() ? &i->value : 0;
    169     LayoutSize oldSize;
    170     bool isFirstResize = true;
    171     if (innerMap) {
    172         LayerSizeMap::iterator j = innerMap->find(layer);
    173         if (j != innerMap->end()) {
    174             isFirstResize = false;
    175             oldSize = j->value;
    176         }
    177     }
    178 
    179     const AffineTransform& currentTransform = context->getCTM();
    180     bool contextIsScaled = !currentTransform.isIdentityOrTranslationOrFlipped();
    181 
    182     // Make sure to use the unzoomed image size, since if a full page zoom is in effect, the image
    183     // is actually being scaled.
    184     LayoutSize scaledImageSize = currentTransform.mapSize(image->size());
    185     LayoutSize scaledLayoutSize = currentTransform.mapSize(roundedIntSize(layoutSize));
    186 
    187     // If the containing FrameView is being resized, paint at low quality until resizing is finished.
    188     if (LocalFrame* frame = object->document().frame()) {
    189         bool frameViewIsCurrentlyInLiveResize = frame->view() && frame->view()->inLiveResize();
    190         if (frameViewIsCurrentlyInLiveResize) {
    191             set(object, innerMap, layer, scaledLayoutSize);
    192             restartTimer();
    193             m_liveResizeOptimizationIsActive = true;
    194             return true;
    195         }
    196         if (m_liveResizeOptimizationIsActive) {
    197             // Live resize has ended, paint in HQ and remove this object from the list.
    198             removeLayer(object, innerMap, layer);
    199             return false;
    200         }
    201     }
    202 
    203     // See crbug.com/382491. This test is insufficient to ensure that there is no scale
    204     // applied in the compositor, but it is probably adequate here. In the worst case we
    205     // draw at high quality when we need not.
    206     if (!contextIsScaled && scaledLayoutSize == scaledImageSize) {
    207         // There is no scale in effect. If we had a scale in effect before, we can just remove this object from the list.
    208         removeLayer(object, innerMap, layer);
    209         return false;
    210     }
    211 
    212     // If an animated resize is active, paint in low quality and kick the timer ahead.
    213     if (m_animatedResizeIsActive) {
    214         set(object, innerMap, layer, scaledLayoutSize);
    215         restartTimer();
    216         return true;
    217     }
    218     // If this is the first time resizing this image, or its size is the
    219     // same as the last resize, draw at high res, but record the paint
    220     // size and set the timer.
    221     if (isFirstResize || oldSize == scaledLayoutSize) {
    222         restartTimer();
    223         set(object, innerMap, layer, scaledLayoutSize);
    224         return false;
    225     }
    226     // If the timer is no longer active, draw at high quality and don't
    227     // set the timer.
    228     if (!m_timer.isActive()) {
    229         removeLayer(object, innerMap, layer);
    230         return false;
    231     }
    232     // This object has been resized to two different sizes while the timer
    233     // is active, so draw at low quality, set the flag for animated resizes and
    234     // the object to the list for high quality redraw.
    235     set(object, innerMap, layer, scaledLayoutSize);
    236     m_animatedResizeIsActive = true;
    237     restartTimer();
    238     return true;
    239 }
    240 
    241 } // namespace blink
    242