Changeset 241840 in webkit

Timestamp:

Feb 20, 2019 2:28:13 PM (5 years ago)

Author:

commit-queue@webkit.org

Message:

drawImage() clears the canvas if it's the source of the image and globalCompositeOperation is "copy"
​https://bugs.webkit.org/show_bug.cgi?id=194746

Patch by Said Abou-Hallawa <​sabouhallawa@apple.com> on 2019-02-20
Reviewed by Dean Jackson.

Source/WebCore:

Test: fast/canvas/canvas-drawImage-composite-copy.html

If the source canvas of drawImage() is the same as the destination and
globalCompositeOperation is set to "copy", copy the srcRect from the
canvas to a temporary buffer before calling clearCanvas() then drawImage
from this temporary buffer.

• html/canvas/CanvasRenderingContext2DBase.cpp:

(WebCore::CanvasRenderingContext2DBase::drawImage):

• platform/graphics/ImageBuffer.cpp:

(WebCore::ImageBuffer::copyRectToBuffer):

• platform/graphics/ImageBuffer.h:

LayoutTests:

• fast/canvas/canvas-drawImage-composite-copy-expected.html: Added.
• fast/canvas/canvas-drawImage-composite-copy.html: Added.

Location:

trunk

Files:

• LayoutTests/ChangeLog (modified) (1 diff)
• LayoutTests/fast/canvas/canvas-drawImage-composite-copy-expected.html (added)
• LayoutTests/fast/canvas/canvas-drawImage-composite-copy.html (added)
• Source/WebCore/ChangeLog (modified) (1 diff)
• Source/WebCore/html/canvas/CanvasRenderingContext2DBase.cpp (modified) (1 diff)
• Source/WebCore/platform/graphics/ImageBuffer.cpp (modified) (1 diff)
• Source/WebCore/platform/graphics/ImageBuffer.h (modified) (1 diff)

trunk/LayoutTests/ChangeLog

@@ +1 @@
+2019-02-20  Said Abou-Hallawa  <sabouhallawa@apple.com>
+
+        drawImage() clears the canvas if it's the source of the image and globalCompositeOperation is "copy"
+        https://bugs.webkit.org/show_bug.cgi?id=194746
+
+        Reviewed by Dean Jackson.
+
+        * fast/canvas/canvas-drawImage-composite-copy-expected.html: Added.
+        * fast/canvas/canvas-drawImage-composite-copy.html: Added.
+
 2019-02-20  Shawn Roberts  <sroberts@apple.com>
 

trunk/Source/WebCore/ChangeLog

@@ +1 @@
+2019-02-20  Said Abou-Hallawa  <sabouhallawa@apple.com>
+
+        drawImage() clears the canvas if it's the source of the image and globalCompositeOperation is "copy"
+        https://bugs.webkit.org/show_bug.cgi?id=194746
+
+        Reviewed by Dean Jackson.
+
+        Test: fast/canvas/canvas-drawImage-composite-copy.html
+
+        If the source canvas of drawImage() is the same as the destination and
+        globalCompositeOperation is set to "copy", copy the srcRect from the 
+        canvas to a temporary buffer before calling clearCanvas() then drawImage
+        from this temporary buffer.
+
+        * html/canvas/CanvasRenderingContext2DBase.cpp:
+        (WebCore::CanvasRenderingContext2DBase::drawImage):
+        * platform/graphics/ImageBuffer.cpp:
+        (WebCore::ImageBuffer::copyRectToBuffer):
+        * platform/graphics/ImageBuffer.h:
+
 2019-02-20  Simon Fraser  <simon.fraser@apple.com>
 

trunk/Source/WebCore/html/canvas/CanvasRenderingContext2DBase.cpp

@@ -1644 +1644 @@
         didDrawEntireCanvas();
     } else if (state().globalComposite == CompositeCopy) {
-        clearCanvas();
-        c->drawImageBuffer(*buffer, dstRect, srcRect, ImagePaintingOptions(state().globalComposite, state().globalBlend));
+        if (&sourceCanvas == &canvasBase()) {
+            if (auto copy = buffer->copyRectToBuffer(srcRect, ColorSpaceSRGB, *c)) {
+                clearCanvas();
+                c->drawImageBuffer(*copy, dstRect, { { }, srcRect.size() }, ImagePaintingOptions(state().globalComposite, state().globalBlend));
+            }
+        } else {
+            clearCanvas();
+            c->drawImageBuffer(*buffer, dstRect, srcRect, ImagePaintingOptions(state().globalComposite, state().globalBlend));
+        }
         didDrawEntireCanvas();
     } else {

trunk/Source/WebCore/platform/graphics/ImageBuffer.cpp

@@ -195 +195 @@
 #endif
 
+std::unique_ptr<ImageBuffer> ImageBuffer::copyRectToBuffer(const FloatRect& rect, ColorSpace colorSpace, const GraphicsContext& context)
+{
+    if (rect.isEmpty())
+        return nullptr;
+
+    IntSize scaledSize = ImageBuffer::compatibleBufferSize(rect.size(), context);
+
+    auto buffer = ImageBuffer::createCompatibleBuffer(scaledSize, 1, colorSpace, context);
+    if (!buffer)
+        return nullptr;
+
+    buffer->context().drawImageBuffer(*this, -rect.location());
+    return buffer;
+}
+
 std::unique_ptr<ImageBuffer> ImageBuffer::createCompatibleBuffer(const FloatSize& size, ColorSpace colorSpace, const GraphicsContext& context)
 {

trunk/Source/WebCore/platform/graphics/ImageBuffer.h

@@ -71 +71 @@
     WEBCORE_EXPORT static std::unique_ptr<ImageBuffer> create(const FloatSize&, RenderingMode, const GraphicsContext*, float resolutionScale = 1, ColorSpace = ColorSpaceSRGB, const HostWindow* = nullptr);
 #endif
+
+    // Create an image buffer compatible with the context and copy rect from this buffer into this new one.
+    std::unique_ptr<ImageBuffer> copyRectToBuffer(const FloatRect&, ColorSpace, const GraphicsContext&);
 
     // Create an image buffer compatible with the context, with suitable resolution for drawing into the buffer and then into this context.