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 70 matching lines @@
     , m_contextProvider(contextProvider)
     , m_imageBuffer(0)
     , m_msaaSampleCount(msaaSampleCount)
     , m_bytesAllocated(0)
     , m_didRecordDrawCommand(false)
     , m_isSurfaceValid(true)
     , m_framesPending(0)
     , m_framesSinceMailboxRelease(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_releasedMailboxInfoIndex(InvalidMailboxIndex)
 {
     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->setFilterLevel(m_filterLevel);
     m_canvas->setNotificationClient(this);
 #ifndef NDEBUG
     canvas2DLayerBridgeInstanceCounter.increment();
 #endif
 }
 
 Canvas2DLayerBridge::~Canvas2DLayerBridge()
 {
     ASSERT(m_destructionInProgress);
     ASSERT(!Canvas2DLayerManager::get().isInList(this));
@@ skipping 28 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)
+{
+    printf("Canvas2dLayerBridge::setFilterLevel %d\n", filterLevel);

[Justin Novosad, 2014/10/28 20:27:44]

Don't commit this line.

[jackhou1, 2014/10/29 00:56:39]

Sorry. I'll remove all these before asking for a final review. Leaving them in
for now until I get it all working.

+    ASSERT(!m_destructionInProgress);
+    if (m_filterLevel != filterLevel) {
+        m_filterLevel = filterLevel;
+        m_layer->setFilterLevel(m_filterLevel);
+        m_imageBuffer->notifySurfaceInvalid();
+    }
+}
+
 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 242 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();
 
     MailboxInfo* mailboxInfo = createMailboxInfo();
     mailboxInfo->m_status = MailboxInUse;
     mailboxInfo->m_image = image;
 
     ASSERT(mailboxInfo->m_mailbox.syncPoint == 0);
     ASSERT(mailboxInfo->m_image.get());
 
     // set m_parentLayerBridge to make sure 'this' stays alive as long as it has
     // live mailboxes
     ASSERT(!mailboxInfo->m_parentLayerBridge);
     mailboxInfo->m_parentLayerBridge = this;
     *outMailbox = mailboxInfo->m_mailbox;
 
     GrContext* grContext = m_contextProvider->grContext();
     if (!grContext)
         return true; // for testing: skip gl stuff when using a mock graphics context.
 
     ASSERT(mailboxInfo->m_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);

[Justin Novosad, 2014/10/28 20:27:44]

Does this even matter?

[jackhou1, 2014/10/29 00:56:39]

Without this change, a pixelated canvas is intially drawn properly, but when I
switch to another tab and back, it's blurry again. I'm not sure exactly why that
happens, maybe it should be fixed somewhere else in the code?

     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);
     webContext->produceTextureCHROMIUM(GL_TEXTURE_2D, mailboxInfo->m_mailbox.name);
     if (isHidden()) {
         // With hidden canvases, we release the SkImage immediately because
         // there is no need for animations to be double buffered.
         mailboxInfo->m_image.clear();
     } else {
         webContext->flush();
         mailboxInfo->m_mailbox.syncPoint = webContext->insertSyncPoint();
@@ skipping 132 matching lines @@
     // This copy constructor should only be used for Vector reallocation
     // 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();
     m_status = other.m_status;
 }
 
 } // namespace blink