tree 949659c1d5eb5a14830b64b3a8609d17af6bc842
parent 4490549bb9093dc44dc579a5947718c93cc5a4ec
author Phillip Webb <pwebb@pivotal.io> 1450781414 +0000
committer Lakshmi Shanmugam <lshanmug@in.ibm.com> 1544766583 -0500

Bug 366471 - Improve OSX scroll performance with drawText caching

Add caching to GC.drawText to prevent multiple calls with the same
single
character from needed to perform expensive layout operations. Any call
to
GC.drawText() that is rendering a single character on a transparent
background is now a cache candidate.

The cache is limited to 20 items and is specifically designed to work
well
with classes such as WhitespaceCharacterPainter which frequently call
drawText() but operate with a relatively small set of characters.

Change-Id: I0ac4e3478e212ba5e410c5a06a6827279143f7be
Also-by: Karsten Thoms <karsten.thoms@itemis.de>
Signed-off-by: Phillip Webb <pwebb@pivotal.io>