Implement image-rendering:pixelated for accelerated 2D canvases.

Source/platform/graphics/Canvas2DLayerBridge.cpp

 /*
  * Copyright (C) 2012 Google Inc. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions
  * are met:
  *
  * 1.  Redistributions of source code must retain the above copyright
  *     notice, this list of conditions and the following disclaimer.
  * 2.  Redistributions in binary form must reproduce the above copyright
@@ skipping 73 matching lines @@
     , m_surface(surface)
     , m_contextProvider(contextProvider)
     , m_imageBuffer(0)
     , m_msaaSampleCount(msaaSampleCount)
     , m_bytesAllocated(0)
     , m_didRecordDrawCommand(false)
     , m_isSurfaceValid(true)
     , m_framesPending(0)
     , m_destructionInProgress(false)
     , m_rateLimitingEnabled(false)
+    , m_filterLevel(SkPaint::kLow_FilterLevel)
     , m_isHidden(false)
     , m_next(0)
     , m_prev(0)
     , m_lastImageId(0)
+    , m_lastFilter(GL_LINEAR)
     , m_opacityMode(opacityMode)
 {
     ASSERT(m_canvas);
     ASSERT(m_surface);
     ASSERT(m_contextProvider);
     // Used by browser tests to detect the use of a Canvas2DLayerBridge.
     TRACE_EVENT_INSTANT0("test_gpu", "Canvas2DLayerBridgeCreation");
     m_layer = adoptPtr(Platform::current()->compositorSupport()->createExternalTextureLayer(this));
     m_layer->setOpaque(opacityMode == Opaque);
     m_layer->setBlendBackgroundColor(opacityMode != Opaque);
     GraphicsLayer::registerContentsLayer(m_layer->layer());
     m_layer->setRateLimitContext(m_rateLimitingEnabled);
+    m_layer->setNearestNeighbor(m_filterLevel == SkPaint::kNone_FilterLevel);
     m_canvas->setNotificationClient(this);
 #ifndef NDEBUG
     canvas2DLayerBridgeInstanceCounter.increment();
 #endif
 }
 
 Canvas2DLayerBridge::~Canvas2DLayerBridge()
 {
     ASSERT(m_destructionInProgress);
     ASSERT(!Canvas2DLayerManager::get().isInList(this));
@@ skipping 20 matching lines @@
     m_layer->clearTexture();
     // Orphaning the layer is required to trigger the recration of a new layer
     // in the case where destruction is caused by a canvas resize. Test:
     // virtual/gpu/fast/canvas/canvas-resize-after-paint-without-layout.html
     m_layer->layer()->removeFromParent();
     // To anyone who ever hits this assert: Please update crbug.com/344666
     // with repro steps.
     ASSERT(!m_bytesAllocated);
 }
 
+void Canvas2DLayerBridge::setFilterLevel(SkPaint::FilterLevel filterLevel)
+{
+    ASSERT(!m_destructionInProgress);
+    m_filterLevel = filterLevel;
+    m_layer->setNearestNeighbor(m_filterLevel == SkPaint::kNone_FilterLevel);
+}
+
 void Canvas2DLayerBridge::setIsHidden(bool hidden)
 {
     ASSERT(!m_destructionInProgress);
     bool newHiddenValue = hidden || m_destructionInProgress;
     if (m_isHidden == newHiddenValue)
         return;
 
     m_isHidden = newHiddenValue;
     if (isHidden()) {
         freeTransientResources();
@@ skipping 194 matching lines @@
     WebGraphicsContext3D* webContext = context();
 
     // Release to skia textures that were previouosly released by the
     // compositor. We do this before acquiring the next snapshot in
     // order to cap maximum gpu memory consumption.
     flush();
 
     RefPtr<SkImage> image = adoptRef(m_canvas->newImageSnapshot());
 
     // Early exit if canvas was not drawn to since last prepareMailbox
-    if (image->uniqueID() == m_lastImageId)
+    GLenum filter = m_filterLevel == SkPaint::kNone_FilterLevel ? GL_NEAREST : GL_LINEAR;
+    if (image->uniqueID() == m_lastImageId && filter == m_lastFilter)
         return false;
     m_lastImageId = image->uniqueID();
+    m_lastFilter = filter;
 
     {
         MailboxInfo tmp;
         tmp.m_image = image;
         tmp.m_parentLayerBridge = this;
         m_mailboxes.prepend(tmp);
     }
     MailboxInfo& mailboxInfo = m_mailboxes.first();
 
+    mailboxInfo.m_mailbox.nearestNeighbor = filter == GL_NEAREST;
+
     GrContext* grContext = m_contextProvider->grContext();
     if (!grContext)
         return true; // for testing: skip gl stuff when using a mock graphics context.
 
     ASSERT(image->getTexture());
 
     // Because of texture sharing with the compositor, we must invalidate
     // the state cached in skia so that the deferred copy on write
     // in SkSurface_Gpu does not make any false assumptions.
     mailboxInfo.m_image->getTexture()->textureParamsModified();
 
     webContext->bindTexture(GL_TEXTURE_2D, mailboxInfo.m_image->getTexture()->getTextureHandle());
-    webContext->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_LINEAR);
-    webContext->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_LINEAR);
+    webContext->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, filter);
+    webContext->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, filter);
     webContext->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
     webContext->texParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
 
     // Re-use the texture's existing mailbox, if there is one.
     if (image->getTexture()->getCustomData()) {
         ASSERT(image->getTexture()->getCustomData()->size() == sizeof(mailboxInfo.m_mailbox.name));
         memcpy(&mailboxInfo.m_mailbox.name[0], image->getTexture()->getCustomData()->data(), sizeof(mailboxInfo.m_mailbox.name));
     } else {
         context()->genMailboxCHROMIUM(mailboxInfo.m_mailbox.name);
         RefPtr<SkData> mialboxNameData = adoptRef(SkData::NewWithCopy(&mailboxInfo.m_mailbox.name[0], sizeof(mailboxInfo.m_mailbox.name)));
@@ skipping 96 matching lines @@
 Canvas2DLayerBridge::MailboxInfo::MailboxInfo(const MailboxInfo& other) {
     // This copy constructor should only be used for Deque::prepend
     // Assuming 'other' is to be destroyed, we transfer m_image and
     // m_parentLayerBridge ownership rather than do a refcount dance.
     memcpy(&m_mailbox, &other.m_mailbox, sizeof(m_mailbox));
     m_image = const_cast<MailboxInfo*>(&other)->m_image.release();
     m_parentLayerBridge = const_cast<MailboxInfo*>(&other)->m_parentLayerBridge.release();
 }
 
 } // namespace blink