OS X Preview fails to scale PDF fully when resizing window fast

Number:rdar://20069961 Date Originated:2015-03-06
Status:Open Resolved:
Product:OS X Preview Product Version:8.0
Classification:Usability Reproducible:Sometimes
If you resize a window displaying a PDF in Preview very fast, sometimes Preview fails to keep up with the mouse movement.

Steps to Reproduce:
1. Open a PDF file in Preview.
2. Select View > Single Page in the Preview menubar.
3. With mouse, grab bottom-right corner of window and resize to make window very small.
4. With mouse, grab bottom-right corner of window and resize by dragging VERY FAST.

Expected Results:
I expect Preview to scale the page so that it always fills the entire space available in the window.

Actual Results:
When I drag VERY FAST, Preview fails to "keep up" and the scaled PDF at the end of the dragging does not fill the entire window.

A further "nudge" of the window size is required to force Preview to refresh and properly fill the space available.

See attached MP4 file, which illustrates the problem:


Notice how, after the quick dragging motion to resize, the PDF page does not quite fill the entire window. After a pause, I nudged by dragging the corner a little bit more, and THEN finally Preview finished scaling the PDF page to fill the window. 

OS X 10.10.2 (14C109)
Preview 8.0

This problem has a very problematic impact on Keyboard Maestro, because its window resize action effectively mimics a very fast mouse movement and is severely affected by this problem when applied to windows in Preview.

2014 Mac Pro with 32 GB of RAM running OS X 10.10.2 + Sharp PN-K321 Display and Apple Cinema HD Display


Closed by Apple as duplicate

2015-03-10: Closed by Apple as duplicate of BR #19987707.

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