commit | 3b46fce6fec566e93a8a6b90df113272d203aafc | [log] [tgz] |
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author | Søren Sandmann Pedersen <soren.sandmann@gmail.com> | Tue Aug 30 22:03:12 2016 -0700 |

committer | Søren Sandmann Pedersen <soren.sandmann@gmail.com> | Fri Sep 02 00:40:12 2016 -0400 |

tree | 51a1b131f919eec4e978f64aa13489a418045e47 | |

parent | 8855b3a2a231ab348c02c0d92f0051b079eabfa3 [diff] |

pixman-filter: Speed up BOX/BOX filter The convolution of two BOX filters is simply the length of the interval where both are non-zero, so we can simply return width from the integral() function because the integration region has already been restricted to be such that both functions are non-zero on it. This is both faster and more accurate than doing numerical integration. This patch is based on one by Bill Spitzak https://lists.freedesktop.org/archives/pixman/2016-March/004446.html with these changes: - Rebased to not assume any changes in the arguments to integral(). - Dropped the multiplication by scale - Added more details in the commit message. Signed-off-by: Søren Sandmann <soren.sandmann@gmail.com> Reviewed-by: Bill Spitzak <spitzak@gmail.com>

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