tree 70331d37a6163369a8140fe2f40c2631959f0bc3
parent ff75b2d8243f18b92dea12ec46be808d0223c3fe
author Nigel Tao <nigeltao@golang.org> 1426649355 +1100
committer Nigel Tao <nigeltao@golang.org> 1426658693 +0000

draw: add a fast path for Gray src images.

benchmark                      old ns/op      new ns/op      delta
BenchmarkScaleSrcGray          9296680        552705         -94.05%
BenchmarkTformABSrcGray        6323894        817986         -87.07%
BenchmarkTformCRSrcGray        39229583       4193194        -89.31%

Change-Id: Ie7d43dfe323d49b245b47c3206b5aad2b50cb7fb
Reviewed-on: https://go-review.googlesource.com/7711
Reviewed-by: Rob Pike <r@golang.org>