code review 2151042: image: introduce Config type and DecodeConfig function,...

image: introduce Config type and DecodeConfig function, to decode an
image's color model and dimensions without allocating and decoding its
actual pixels.

Fixes issue 695.

[nigeltao, 2010-09-03 06:15:56]

Hello r (cc: golang-dev@googlegroups.com),

I'd like you to review this change.

[r, 2010-09-03 06:34:39]

LGTM

http://codereview.appspot.com/2151042/diff/2001/3001
File src/pkg/image/format.go (right):

http://codereview.appspot.com/2151042/diff/2001/3001#newcode84
src/pkg/image/format.go:84: func DecodeConfig(r io.Reader) (c Config, formatName
string, err os.Error) {
the names aren't buying you much here, except the comment doesn't explain the
return value.

http://codereview.appspot.com/2151042/diff/2001/3003
File src/pkg/image/jpeg/reader.go (right):

http://codereview.appspot.com/2151042/diff/2001/3003#newcode367
src/pkg/image/jpeg/reader.go:367: // decode reads a JPEG formatted image from r
and returns it as an image.Image.
see below

http://codereview.appspot.com/2151042/diff/2001/3003#newcode368
src/pkg/image/jpeg/reader.go:368: func (d *decoder) decode(r io.Reader,
metadataOnly bool) (image.Image, os.Error) {
metaData? maybe not

http://codereview.appspot.com/2151042/diff/2001/3003#newcode437
src/pkg/image/jpeg/reader.go:437: // Decode reads a JPEG formatted image from r
and returns it as an image.Image.
s/ formatted/-formatted/ or drop it

http://codereview.appspot.com/2151042/diff/2001/3003#newcode443
src/pkg/image/jpeg/reader.go:443: // DecodeConfig returns the color model and
dimensions of a JPEG formatted
ditto

http://codereview.appspot.com/2151042/diff/2001/3004
File src/pkg/image/png/reader.go (right):

http://codereview.appspot.com/2151042/diff/2001/3004#newcode546
src/pkg/image/png/reader.go:546: // DecodeConfig returns the color model and
dimensions of a PNG formatted
s/ formatted// or maybe s//-formatted/

[nigeltao, 2010-09-03 08:03:13]

*** Submitted as http://code.google.com/p/go/source/detail?r=8267941c1cbc ***

image: introduce Config type and DecodeConfig function, to decode an
image's color model and dimensions without allocating and decoding its
actual pixels.

Fixes issue 695.

R=r
CC=golang-dev
http://codereview.appspot.com/2151042