[webkit-reviews] review denied: [Bug 93292] [Chromium] Pinch Zoom prototype tracking issue. : [Attachment 163130] Alpha version of the new pinch zoom algorithm.

[bugzilla-daemon at webkit.org]

Jeff Timanus <twiz at chromium.org> has denied  review:
Bug 93292: [Chromium] Pinch Zoom prototype tracking issue.
https://bugs.webkit.org/show_bug.cgi?id=93292

Attachment 163130: Alpha version of the new pinch zoom algorithm.
https://bugs.webkit.org/attachment.cgi?id=163130&action=review

------- Additional Comments from Jeff Timanus <twiz at chromium.org>
Patch indicating a general idea of the new pinch zoom algorithm.

Style and variable naming still need to be addressed, but there are functional
issues that I'm still trying to track down.  The naming of the blue-box
viewport is to correspond with the terminology of the new design.

High-level summary:
 - On pinch, the Impl thread maintains a 'blue box' viewport.  The entire page
is scaled, and this viewport moves within the scaled page.  
 - Movement of the blue-box viewport is not reflected by the current scroll-bar
position.  This viewport can only be positioned via a pinch-zoom move, or
during a scroll-to-edge-of-page event.
 - During scroll, the main page is scrolled first.  If it is not possible for
the page to scroll, then the blue box viewport applies the scroll.

I'd like to request some assistance resolving bugs in the following areas. 
Please look for in-line comments for further explanation.
 - The center of the pinch zoom is not correct.  I believe this is because of
either the order that the transformations are applied, or because I'm confusing
the coordinates in which the layers reside.
 - The performance of the scroll is very bad.  I think this is because I'm
somehow triggering re-painting of the tiles.
 - I am unable to scroll to the bottom of the page.  This is likely a
max-scroll position problem.