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