[webkit-changes] [WebKit/WebKit] 6c12bd: [UnifiedPDF] Prepare for sharing some PDF page pai...

[Simon Fraser]

  Branch: refs/heads/main
  Home:   https://github.com/WebKit/WebKit
  Commit: 6c12bd338a35f85ab2f42e906e2dfc985c745e7b
      https://github.com/WebKit/WebKit/commit/6c12bd338a35f85ab2f42e906e2dfc985c745e7b
  Author: Simon Fraser <simon.fraser at apple.com>
  Date:   2024-02-13 (Tue, 13 Feb 2024)

  Changed paths:
    M Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.h
    M Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.mm

  Log Message:
  -----------
  [UnifiedPDF] Prepare for sharing some PDF page painting data with async rendering
https://bugs.webkit.org/show_bug.cgi?id=269270
rdar://122851341

Reviewed by Tim Horton.

Async PDF painting will need to be able to paint the set of pages that intersect
with a given clipRect (corresponding to a tile) in m_contentLayer coordinates,
in a way that does not use the thread-unsafe PDFDocumentLayout.

So make a little data structure, `PDFPageCoverage` to hold enough information about
the set of pages that intersect the given rect, and their geometry.

`UnifiedPDFPlugin::pageCoverageForRect()` computes this data, and  `UnifiedPDFPlugin::paintPDFContent()`
is updated to use it.

Also pass a clipRect to `UnifiedPDFPlugin::paintPDFOverlays()` to avoid filling a rect outside the clip,
and make the code easier to read.

* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.h:
* Source/WebKit/WebProcess/Plugins/PDF/UnifiedPDF/UnifiedPDFPlugin.mm:
(WebKit::UnifiedPDFPlugin::pageCoverageForRect const):
(WebKit::UnifiedPDFPlugin::paintPDFContent):
(WebKit::UnifiedPDFPlugin::paintPDFOverlays):

Canonical link: https://commits.webkit.org/274552@main