2008.11.11 17:28 "[Tiff] Error in initial post for PLANARCONFIG == SEPARATE", by Richard Nolde

>

> 1. Writing scanlines with PLANARCONFIG == SEPARATE (Richard Nolde) There was an error in my initial post that made my intent unclear:

Since the data are compressed/stored on a per scanline basis, I wanted to write the data for each sample of a given row of the image to successive scan lines within one strip to speed up access when only a part of the image is being used.

Strip 1
Scanline 1 RRRRRRRRR
Scanline 2 GGGGGGGG
Scanline 3 BBBBBBBBB

should have been

Strip 1
Scanline 1 RRRRRRRRR
Scanline 1 GGGGGGGGG
Scanline 1 BBBBBBBBB

Scanline 2 RRRRRRRRR
Scanline 2 GGGGGGGGG
Scanline 2 BBBBBBBBB

Scanline 3 RRRRRRRRR
Scanline 3 GGGGGGGGG
Scanline 3 BBBBBBBBB

Another possibility would be
Strip 1
Scanline 1 RRRRRRRRR
Scanline 2 RRRRRRRRR
Scanline 3 RRRRRRRRR

Scanline 1 GGGGGGGGG
Scanline 2 GGGGGGGGG
Scanline 3 GGGGGGGGG

Scanline 1 BBBBBBBBB
Scanline 2 BBBBBBBBB
Scanline 3 BBBBBBBBB

Strip 2
...

I guess the problems is that the TIFF Spec doesn't provide any way to distinguish among these layouts so a reader would have no way to know which sequence they represent. It looks like PLANNARCONFIG == SEPARATE is an all or nothing model.

Richard Nolde