Commit Graph

8 Commits

Author SHA1 Message Date
Nigel Tao
87013da148 draw: implement NearestNeighbor and ApproxBiLinear Transform.
Change-Id: I70a5e3703dea436354e9591fce7b704ec749c2d1
Reviewed-on: https://go-review.googlesource.com/7541
Reviewed-by: Rob Pike <r@golang.org>
2015-03-16 23:32:22 +00:00
Nigel Tao
efa0c0977f draw: implement Copy; add an example_test.
Change-Id: Ia9cceac17c0326702530eac3a205308b02b85986
Reviewed-on: https://go-review.googlesource.com/7262
Reviewed-by: Rob Pike <r@golang.org>
2015-03-11 22:37:25 +00:00
Nigel Tao
08593990c4 draw: add Transformer and Option types.
Just stub implementations for now. Actual implementations will be
follow-up changes.

Change-Id: Id21d9042a2073c2dc0f78c9977c4940f000a41df
Reviewed-on: https://go-review.googlesource.com/6805
Reviewed-by: Rob Pike <r@golang.org>
2015-03-10 00:41:02 +00:00
Nigel Tao
93a98e7805 draw: fix a comment typo.
Change-Id: I6d34d091514915333e488cee9e2ddb5a9d78b6a5
Reviewed-on: https://go-review.googlesource.com/6801
Reviewed-by: David Symonds <dsymonds@golang.org>
2015-03-05 00:26:58 +00:00
Nigel Tao
2c27a34d37 draw: make Scale an Interpolator method instead of a function.
This means that only Kernel values have a NewScaler method, which
re-uses computation when scaling multiple images of the same dst and src
dimensions. The NearestNeighbor and ApproxBiLinear scalers don't get any
pre-computation to re-use, so don't need a NewScaler method just to
satisfy the previous Interpolator interface. As a small bonus, NN.Scale
and ABL.Scale should no longer allocate on the fast paths.

This change is consistent the upcoming Transformer method, so that the
Interpolator interface will be

type Interpolator interface {
	Scale(etc)
	Transform(etc)
}

instead of

type Interpolator interface {
	NewScaler(etc) Scaler
	Transform(etc)
}

I don't have a good theory for why the "func (ablInterpolator)
scale_RGBA_RGBA" benchmark is such a dramatic improvement, but at least
it's in the right direction. I'm calling the other benchmark changes as
noise.

benchmark                     old ns/op      new ns/op      delta
BenchmarkScaleLargeDownNN     3233406        3169060        -1.99%
BenchmarkScaleLargeDownAB     12018178       12011348       -0.06%
BenchmarkScaleLargeDownBL     1420827834     1409335695     -0.81%
BenchmarkScaleLargeDownCR     2820669690     2795534035     -0.89%
BenchmarkScaleDownNN          866628         869241         +0.30%
BenchmarkScaleDownAB          3175963        3216041        +1.26%
BenchmarkScaleDownBL          26639767       26677003       +0.14%
BenchmarkScaleDownCR          51720996       51621628       -0.19%
BenchmarkScaleUpNN            42758485       43258611       +1.17%
BenchmarkScaleUpAB            156693813      156943367      +0.16%
BenchmarkScaleUpBL            69511444       69621698       +0.16%
BenchmarkScaleUpCR            124530191      124885601      +0.29%
BenchmarkScaleSrcGray         8992205        9129321        +1.52%
BenchmarkScaleSrcNRGBA        9807837        9894466        +0.88%
BenchmarkScaleSrcRGBA         1333188        1104282        -17.17%
BenchmarkScaleSrcUniform      1147788        1162488        +1.28%
BenchmarkScaleSrcYCbCr        12164542       12305373       +1.16%

Change-Id: I2aee6c392eb7437e843260775aed97ce145b4d47
Reviewed-on: https://go-review.googlesource.com/6556
Reviewed-by: Rob Pike <r@golang.org>
2015-03-04 22:50:18 +00:00
Nigel Tao
999c3975a8 draw: autogenerate impl.go.
Adding fast paths for concrete dst and src image types will be follow-up
changes.

Change-Id: Ib23e3cc46d9c7a52ebd5eddfbad09177b0b421af
Reviewed-on: https://go-review.googlesource.com/5417
Reviewed-by: Rob Pike <r@golang.org>
2015-02-24 00:55:15 +00:00
Nigel Tao
2a1231edb8 draw: factor out the Scale implementations.
This is just a copy/paste/rename in anticipation of automatically
generating fast-path code for specific dst-image types and src-image
types, a la the standard library's image/draw package.

Change-Id: If6385b347cb5e1d134b0ce841ef38ed4450a6fef
Reviewed-on: https://go-review.googlesource.com/5252
Reviewed-by: David Symonds <dsymonds@golang.org>
2015-02-20 07:27:42 +00:00
Nigel Tao
96b77d5c7a draw: new package, a superset of the standard library's image/draw
package, including the ability to scale an image.

Design discussion:
https://groups.google.com/forum/#!topic/golang-dev/B7-OrWdheic

Previous code review (when Go used hg instead of git):
https://codereview.appspot.com/101670045

New benchmarks:
BenchmarkScaleLargeDownNN	     300	   5935174 ns/op
BenchmarkScaleLargeDownAB	     100	  14482372 ns/op
BenchmarkScaleLargeDownBL	       1	1383805986 ns/op
BenchmarkScaleLargeDownCR	       1	2724631789 ns/op
BenchmarkScaleDownNN     	    1000	   1850500 ns/op
BenchmarkScaleDownAB     	     300	   4413499 ns/op
BenchmarkScaleDownBL     	      50	  30498748 ns/op
BenchmarkScaleDownCR     	      20	  58349653 ns/op
BenchmarkScaleUpNN       	      20	  92306475 ns/op
BenchmarkScaleUpAB       	       5	 220103753 ns/op
BenchmarkScaleUpBL       	      10	 122635195 ns/op
BenchmarkScaleUpCR       	      10	 183275927 ns/op

Change-Id: I69d397e68897bae024c7b330a9375fa3e7688591
Reviewed-on: https://go-review.googlesource.com/4210
Reviewed-by: Rob Pike <r@golang.org>
2015-02-17 23:20:02 +00:00