[PATCH] fb: reorder Bresenham error correction to avoid overshoot.

Matt Turner mattst88 at gmail.com
Tue Aug 14 10:54:49 PDT 2012

On Mon, Aug 13, 2012 at 1:57 PM, Keith Packard <keithp at keithp.com> wrote:
> Matt Turner <mattst88 at gmail.com> writes:
>> From: Simon Schubert <2 at 0x2c.org>
>> When fbBresSolid draws a line, it can happen that after the last
>> pixel, the Bresenham error term overflows, and fbBresSolid paints
>> another pixel before adjusting the error term.
>> However, if this happens on the last pixel (len=0), this extra pixel
>> might overshoot the boundary, and, in rare cases, lead to a segfault.
>> Fix this issue by adjusting for the Bresenham error term before
>> drawing the main pixel, not after.
> This looks like something that should land for 1.13, right?
> --
> keith.packard at intel.com

Yeah, I think so.

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