[BlackBerry] Fetch blit rects from a viewport accessor
https://bugs.webkit.org/show_bug.cgi?id=98581
RIM PR 173292

Reviewed by George Staikos.
Internally reviewed by Arvid Nilsson.

Source/WebKit:

Add new ViewportAccessor files to the build.
See Source/WebKit/blackberry/ChangeLog for the
verbose commit message.

* PlatformBlackBerry.cmake:

Source/WebKit/blackberry:

The long-standing userInterfaceBlittedVisibleContentsRect()
method in WebPageClient has long been a major annoyance,
as it returns the source rect for WebKit contents but in
backingstore pixel coordinates. This makes it not only
unwieldy but also terribly fragile, especially when
both pinch zoom and a backingstore re-render both deal
with the same rectangle. On different threads, even.

BlackBerry::Platform now exposes a ViewportAccessor
interface, which can be used to get the various rects
in document coordinates or target pixel coordinates,
both being a better choice than the ones dependent
on an implentation detail.

This commit makes use of this new functionality.
Instead of relying on the passed rectangle to contain
implicit information about the scale factor, we now
track the scale of each backingstore geometry by making
a snapshot of the current WebKit-thread scale when the
geometry is generated. Once the geometry is swapped to
the front, we can then calculate the remaining
backingstore-to-viewport transformation in a threadsafe
way. We now only calculate this if we actually blit from
backingstore tiles and don't go through a configuration
of pure accelerated compositing.

As a result, we are now a lot more robust against
synchonization issues related to backingstore
geometry changes. As an additional gimmick, the scale
is also stored with each tile buffer to doubly secure
that a tile rendered in one scale is not transferred
to a different geometry and then rendered there without
being rerendered at the new scale, even if the rendered
pixel coordinates are still the same.

Having per-geometry scale information also opens up
opportunities to further improve backingstore rendering
later. For instance, we could pre-render a low-res
version of the page onto one buffer and combine that one
with a higher-res array of tiles covering a smaller area.
Or we could steal some tiles from the front geometry to
render them at a new scale while a pinch-zoom operation
is in progress.

No such thing is implemented in this patch though.

In adapting/fixing the backingstore visualization
debug mode and the default background painting in
renderDirectToWindow(), we also introduce new
ViewportAccessor subclasses that can subsequently
be used to replace methods from WebPage and elsewhere.

* Api/BackingStore.cpp:
(BlackBerry::WebKit::BackingStorePrivate::slowScroll):
(BlackBerry::WebKit::BackingStorePrivate::scroll):
(BlackBerry::WebKit::BackingStorePrivate::setBackingStoreRect):
(BlackBerry::WebKit::BackingStorePrivate::scrollBackingStore):
(BlackBerry::WebKit::BackingStorePrivate::renderDirectToWindow):
(BlackBerry::WebKit::BackingStorePrivate::render):
(BlackBerry::WebKit::BackingStorePrivate::paintDefaultBackground):
(BlackBerry::WebKit::BackingStorePrivate::blitVisibleContents):
(BlackBerry::WebKit::BackingStorePrivate::blitHorizontalScrollbar):
(BlackBerry::WebKit::BackingStorePrivate::blitVerticalScrollbar):
(BlackBerry::WebKit::BackingStorePrivate::updateTilesForScrollOrNotRenderedRegion):
(BlackBerry::WebKit::BackingStorePrivate::updateTileMatrixIfNeeded):
(BlackBerry::WebKit::BackingStorePrivate::orientationChanged):
(BlackBerry::WebKit::BackingStorePrivate::createSurfaces):
(BlackBerry::WebKit::BackingStorePrivate::invalidateWindow):
* Api/BackingStore_p.h:
(BlackBerry):
(Platform):
(BlackBerry::WebKit::BackingStoreGeometry::BackingStoreGeometry):
(BlackBerry::WebKit::BackingStoreGeometry::scale):
(BlackBerry::WebKit::BackingStoreGeometry::setScale):
(BackingStoreGeometry):
(BackingStorePrivate):
* Api/WebPage.cpp:
(BlackBerry::WebKit::WebPagePrivate::WebPagePrivate):
(BlackBerry::WebKit::WebPagePrivate::~WebPagePrivate):
(BlackBerry::WebKit::WebPagePrivate::init):
(BlackBerry::WebKit::WebPage::webkitThreadViewportAccessor):
(WebKit):
* Api/WebPage.h:
(Platform):
* Api/WebPageClient.h:
(Platform):
* Api/WebPageCompositor.cpp:
(BlackBerry::WebKit::WebPageCompositorPrivate::animationFrameChanged):
* Api/WebPage_p.h:
(WebKit):
(WebPagePrivate):
* WebKitSupport/BackingStoreTile.cpp:
(BlackBerry::WebKit::TileBuffer::TileBuffer):
(BlackBerry::WebKit::TileBuffer::isRendered):
* WebKitSupport/BackingStoreTile.h:
(TileBuffer):
(BlackBerry::WebKit::TileBuffer::scale):
(BlackBerry::WebKit::TileBuffer::setScale):
* WebKitSupport/BackingStoreVisualizationViewportAccessor.cpp: Added.
(WebKit):
(BlackBerry::WebKit::BackingStoreVisualizationViewportAccessor::BackingStoreVisualizationViewportAccessor):
(BlackBerry::WebKit::BackingStoreVisualizationViewportAccessor::pixelContentsSize):
(BlackBerry::WebKit::BackingStoreVisualizationViewportAccessor::documentContentsSize):
(BlackBerry::WebKit::BackingStoreVisualizationViewportAccessor::pixelScrollPosition):
(BlackBerry::WebKit::BackingStoreVisualizationViewportAccessor::documentScrollPosition):
(BlackBerry::WebKit::BackingStoreVisualizationViewportAccessor::pixelViewportSize):
(BlackBerry::WebKit::BackingStoreVisualizationViewportAccessor::documentViewportSize):
(BlackBerry::WebKit::BackingStoreVisualizationViewportAccessor::destinationSurfaceOffset):
(BlackBerry::WebKit::BackingStoreVisualizationViewportAccessor::scale):
(BlackBerry::WebKit::BackingStoreVisualizationViewportAccessor::state):
* WebKitSupport/BackingStoreVisualizationViewportAccessor.h: Added.
(BlackBerry):
(Platform):
(WebKit):
(BackingStoreVisualizationViewportAccessor):
(BlackBerry::WebKit::BackingStoreVisualizationViewportAccessor::~BackingStoreVisualizationViewportAccessor):
* WebKitSupport/WebKitThreadViewportAccessor.cpp: Added.
(WebKit):
(BlackBerry::WebKit::WebKitThreadViewportAccessor::WebKitThreadViewportAccessor):
(BlackBerry::WebKit::WebKitThreadViewportAccessor::pixelContentsSize):
(BlackBerry::WebKit::WebKitThreadViewportAccessor::documentContentsSize):
(BlackBerry::WebKit::WebKitThreadViewportAccessor::pixelScrollPosition):
(BlackBerry::WebKit::WebKitThreadViewportAccessor::documentScrollPosition):
(BlackBerry::WebKit::WebKitThreadViewportAccessor::pixelViewportSize):
(BlackBerry::WebKit::WebKitThreadViewportAccessor::documentViewportSize):
(BlackBerry::WebKit::WebKitThreadViewportAccessor::destinationSurfaceOffset):
(BlackBerry::WebKit::WebKitThreadViewportAccessor::scale):
* WebKitSupport/WebKitThreadViewportAccessor.h: Added.
(BlackBerry):
(Platform):
(WebKit):
(WebKitThreadViewportAccessor):
(BlackBerry::WebKit::WebKitThreadViewportAccessor::~WebKitThreadViewportAccessor):


git-svn-id: http://svn.webkit.org/repository/webkit/trunk@131257 268f45cc-cd09-0410-ab3c-d52691b4dbfc