by gbulmer:

What steps will reproduce the problem?

Each one of the following results in an image which does not display correctly using
Finder Preview, Safari, Preview or MS Mac Word

1. 'go build'  image04.go (attached)

2. 'go build'  image03.go (attached)

3. move the attached file writer2_test.go into the go.image/tiff directory, run "go
test"
This generates a set of files prefixed with roundtrip., and optionally
"predictor." or "deflate." in the go.image/testdata directory

What is the expected output?
1. A 1D grey gradient, ranging from black on the left to white on the right. Each
vertical line of pixels is the same shade of grey

2. A 2D gray gradient, ranging from black in the top left corner, down to white bottom
right.

3. Images called go.image/testdata/roundtrip.(predictor.)?(deflate.)?xx.tiff should look
identical to the test image go.image/testdata/xx.tiff


What do you see instead?
1. results in an 8-bit tiff (attached gray.tiff) which is displayed by Preview and
Safari as two 1/2 x 1/2 scale image, repeated twice, once top left quadrant, once top
right quadrant. The lower two quadrants seem to be transparent as they are displayed as
the window background colour (mid gray for Preview, white for Safari)

2. results in an 16-bit tiff (attached gray16.tiff) which is also displayed as 1/2 x 1/2
scale in the same way as 1

3. The files where the roundtrip.xx.tiff file (created by tiff.Decode then tiff.Encode)
which do not correctly display on Finder Preview, Mac Safari or Mac Preview are:
go.image/testdata/roundtrip.bw-packbits.tiff
go.image/testdata/roundtrip.video-001-gray-16bit.tiff
go.image/testdata/roundtrip.video-001-gray.tiff

Two original go.image/testdata files are attached gray.tiff and gray16.tiff for
comparison

A colour file which does not display correctly with Finder Preview, Mac Safari or Mac
Preview:
go.image/testdata/roundtrip.predictor.video-001.tiff
It shows as a single vertical line of color pixels in Finder Preview

This file does not display at all
go.image/testdata/roundtrip.video-001-paletted.tiff

One result is in an 8-bit tiff (attached roundtrip.video-001-gray.tiff) which is
displayed as 1/2 x 1/2 scale in the same way as 1 and 2

Which compiler are you using (5g, 6g, 8g, gccgo)?
6g

Which operating system are you using?
Mac (OS X 10.6.8)

Which version are you using?  (run 'go version')
go version go1.1.2 darwin/amd64

Please provide any additional information below.

The writer2_test.go file also generates png.Encoded files. These all seem to be correct,
and match the original test file. 

Attached is an example of the image go.image/testdata/roundtrip.video-001-gray.tiff
printed to pdf (roundtrip.video-001-gray.tiff.pdf) from Preview, showing the two 1/2 x
1/2 scale top 2 quadrant images

Also attached is the same image saved as a .png which shows the 1/2 x 1/2 top quadrants
effect

Also attached is an MS Mac Word document (roundtrip.video-001-gray.tiff.docx) which
displays the image as two 1/2 x 1/2 scale images in the top two quadrants.

HOWEVER Firefox 23.0.1 renders roundtrip.video-001-gray.tiff correctly, so that it looks
the same as the original.

Attachments:

1. writer2_test.go (1106 bytes)
2. roundtrip.video-001-gray.tiff (15648 bytes)
3. roundtrip.video-001-gray.preview.png (11267 bytes)
4. roundtrip.video-001-gray.tiff.pdf (18344 bytes)
5. roundtrip.video-001-gray.tiff.docx (45894 bytes)
6. image04.go (615 bytes)
7. gray.tiff (65734 bytes)
8. image03.go (622 bytes)
9. gray16.tiff (1036 bytes)