Implement "Copy image" for canvas (blink side).

Source/core/editing/Editor.cpp

 /*
  * Copyright (C) 2006, 2007, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies)
  *
  * 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 51 matching lines @@
 #include "core/events/ClipboardEvent.h"
 #include "core/events/KeyboardEvent.h"
 #include "core/events/ScopedEventQueue.h"
 #include "core/events/TextEvent.h"
 #include "core/fetch/ImageResource.h"
 #include "core/fetch/ResourceFetcher.h"
 #include "core/frame/FrameView.h"
 #include "core/frame/LocalFrame.h"
 #include "core/frame/Settings.h"
 #include "core/frame/UseCounter.h"
+#include "core/html/HTMLCanvasElement.h"
 #include "core/html/HTMLImageElement.h"
 #include "core/html/HTMLInputElement.h"
 #include "core/html/HTMLTextAreaElement.h"
 #include "core/html/parser/HTMLParserIdioms.h"
 #include "core/loader/EmptyClients.h"
 #include "core/page/EditorClient.h"
 #include "core/page/EventHandler.h"
 #include "core/page/FocusController.h"
 #include "core/page/Page.h"
 #include "core/rendering/HitTestResult.h"
@@ skipping 337 matching lines @@
     String html = createMarkup(selectedRange, 0, AnnotateForInterchange, false, ResolveNonLocalURLs);
     KURL url = selectedRange->startContainer()->document().url();
     pasteboard->writeHTML(html, url, plainText, canSmartCopyOrDelete());
 }
 
 static void writeImageNodeToPasteboard(Pasteboard* pasteboard, Node* node, const String& title)
 {
     ASSERT(pasteboard);
     ASSERT(node);
 
-    if (!(node->renderer() && node->renderer()->isImage()))
+    RenderObject* renderer = node->renderer();

[yosin_UTC9, 2014/06/20 04:24:10]

It seems it is better to call
|node->document().updateLayoutIgnorePendingStylesheets()| to make sure |node| to
have |RenderObject|.

[zino, 2014/06/20 07:07:09]

Done.

+    if (!renderer)
         return;
 
-    RenderImage* renderer = toRenderImage(node->renderer());
-    ImageResource* cachedImage = renderer->cachedImage();
-    if (!cachedImage || cachedImage->errorOccurred())
+    Image* image = 0;

[yosin_UTC9, 2014/06/20 04:24:10]

nit: How about having helper function to return |Image| from |node|?

Image* image = imageFromNode(node);
if (!image)
   return;

static Image* imageFromNode(const Node* node) 
{
    node->document().updateLayoutIgnorePendingStylesheets();
    RenderObject* renderer = node->renderer();
    if (!renderer || !renderer->isImage())
        return nullptr;
    if (RenderImage* renderImage = toRenderImage(renderer)) {
        ImageResource* cachedImage = renderImage->cachedImage();
        if (!cachedImage || cachedImage->errorOccurred())
            return nullptr;
         return cachedImage->imageForRenderer(renderImage);
     }
     if (renderer->isCanvas())
         return toHTMLCanvasElement(node)->copiedImage();
     return nullptr;
}

[zino, 2014/06/20 07:07:08]

Done.

+    if (renderer->isImage()) {
+        RenderImage* renderImage = toRenderImage(renderer);
+        ImageResource* cachedImage = renderImage->cachedImage();
+        if (!cachedImage || cachedImage->errorOccurred())
+            return;
+        image = cachedImage->imageForRenderer(renderImage);
+    } else if (renderer->isCanvas()) {
+        image = toHTMLCanvasElement(node)->copiedImage();
+    } else {
         return;
-    Image* image = cachedImage->imageForRenderer(renderer);
+    }
     ASSERT(image);
 
     // FIXME: This should probably be reconciled with HitTestResult::absoluteImageURL.
     AtomicString urlString;
     if (isHTMLImageElement(*node) || isHTMLInputElement(*node))
         urlString = toElement(node)->getAttribute(srcAttr);
     else if (isSVGImageElement(*node))
         urlString = toElement(node)->getAttribute(XLinkNames::hrefAttr);
     else if (isHTMLEmbedElement(*node) || isHTMLObjectElement(*node))
         urlString = toElement(node)->imageSourceURL();
+    else if (isHTMLCanvasElement(*node))
+        urlString = AtomicString("data:,[canvas]");

[yosin_UTC9, 2014/06/20 04:24:10]

Just curiosity, what "data:,[canvas]" is? Where do we expand them real URL?

[zino, 2014/06/20 07:07:09]

I thought that the URL is not needed in the case of canvas because it is always
large dataURL.
Many native app uses binary image data usually but some JS app or service seems
to use dataURL instead of binary data.
So, I updated related codes.

     KURL url = urlString.isEmpty() ? KURL() : node->document().completeURL(stripLeadingAndTrailingHTMLSpaces(urlString));
 
     pasteboard->writeImage(image, url, title);
 }
 
 // Returns whether caller should continue with "the default processing", which is the same as
 // the event handler NOT setting the return value to false
 bool Editor::dispatchCPPEvent(const AtomicString &eventType, ClipboardAccessPolicy policy, PasteMode pasteMode)
 {
     Node* target = findEventTargetFromSelection();
@@ skipping 845 matching lines @@
     frame().selection().setShouldShowBlockCursor(m_overwriteModeEnabled);
 }
 
 void Editor::trace(Visitor* visitor)
 {
     visitor->trace(m_lastEditCommand);
     visitor->trace(m_mark);
 }
 
 } // namespace WebCore