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<th>Bug ID</th>
<td><a class="bz_bug_link
bz_status_NEW "
title="NEW - [CG] Add the option to immediacy decode an image frame and control its memory caching"
href="https://bugs.webkit.org/show_bug.cgi?id=163298">163298</a>
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<th>Summary</th>
<td>[CG] Add the option to immediacy decode an image frame and control its memory caching
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<th>Classification</th>
<td>Unclassified
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<th>Product</th>
<td>WebKit
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<th>Version</th>
<td>WebKit Nightly Build
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<th>Hardware</th>
<td>Unspecified
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<th>OS</th>
<td>Unspecified
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<th>Status</th>
<td>NEW
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<th>Severity</th>
<td>Normal
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<th>Priority</th>
<td>P2
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<th>Component</th>
<td>Images
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<th>Assignee</th>
<td>webkit-unassigned@lists.webkit.org
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<th>Reporter</th>
<td>sabouhallawa@apple.com
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<pre>This work is needed for asynchronous image decoding. By default an image frame is decoded only when it'e needed. Usually the image frame is needed when it is drawn. If the image decoding is done on the main thread, two things might happen. The main thread is blocked such that an activity, like scrolling, is not smooth. Secondly the image decoding is slow such that rendering a layout frame is done in more than 16ms, so we miss drawing a frame.
This bug should fix two things. It should add the option to immediately decode an image frame. This should happen on a different thread earlier than the drawing time. The BitmapImage should also control when the image frame is deleted from memory. Currently CG can cache an image frame even if WebKit does not have a reference to it. The only way to guarantee an image frame is removed from memory is to delete the reference to the CGImageSourceRef.</pre>
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