Commit Graph

7 Commits

Author SHA1 Message Date
Benny Siegert
c35a1ecb6c go.image/tiff: use optimized routines for RGBA and NRGBA
Performance for an RGBA image:

benchmark          old ns/op    new ns/op    delta
BenchmarkEncode      1633495         7897  -99.52%

benchmark           old MB/s     new MB/s  speedup
BenchmarkEncode        37.83      7824.96  206.85x

NRGBA images are now encoded as such, the spec calls it
"unassociated alpha".

R=nigeltao, rsc
CC=golang-dev
https://golang.org/cl/6308049
2012-06-13 10:40:38 +10:00
Benny Siegert
de792da79c go.image/tiff: add a benchmark for the encoder
The idea is to see whether it is worthwhile to implement special cases.

On my Mac Book Pro:

BenchmarkEncode	    1000	   1689656 ns/op	  36.69 MB/s

R=nigeltao, minux.ma
CC=golang-dev
https://golang.org/cl/6278050
2012-06-07 09:41:24 +10:00
Nigel Tao
20e9620e99 go.image/tiff: simplify encoding.
R=bsiegert
CC=golang-dev
https://golang.org/cl/5738044
2012-03-07 10:32:33 +11:00
Benny Siegert
f594c3aad5 go.image/tiff: initial support for writing TIFF images
The basic functionality works. Features to add in future CLs:

- compression
- fast paths for image formats that can be directly expressed in TIFF,
  such as RGBA, NRGBA and maybe Gray and Paletted.

R=nigeltao
CC=golang-dev
https://golang.org/cl/5694051
2012-03-05 11:45:47 +11:00
Benny Siegert
324e6dabf0 go.image/tiff: optimize reading uncompressed files from a tiff.buffer.
In case the image is read via a tiff.buffer, avoid copying the
data strip before decoding it. Remove corresponding TODO.
Speeds up reading uncompressed images (which is the common case)
and uses much less memory.

benchmark                      old ns/op    new ns/op    delta
BenchmarkDecodeCompressed        4619438      4630774   +0.25%
BenchmarkDecodeUncompressed       260809       219875  -15.70%

R=nigeltao
CC=golang-dev
https://golang.org/cl/5683050
2012-02-21 11:25:19 +11:00
Nigel Tao
996c335c4a go.image/{bmp,tiff}: move tiff/testdata to testdata.
Add a "compare to golden PNG" test for BMP and TIFF.

R=rsc
CC=golang-dev
https://golang.org/cl/5601054
2012-01-31 14:02:27 +11:00
Nigel Tao
cc3e6234e7 go.image: initial code.
Manual edits to README.
Moved from main Go repository, deleted Makefiles.

Tested with go test code.google.com/p/go.image/...

Fixes golang/go#2797.

R=rsc, rsc, r
CC=golang-dev
https://golang.org/cl/5593053
2012-01-31 11:32:50 +11:00