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

Keith Packard keithp at keithp.com
Mon Aug 13 13:57:15 PDT 2012


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
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