"John Harragin" on wrote...
| Hi I'm running convert using variations of the command...
|
| convert /var/www/html/photos/cyclamin.jpg -resize 320x160 -depth 4 -colo=
| rspace GRAY -type Grayscale /var/www/html/photos/cyclamin.bmp
|
| But=20
| identify -verbose cyclamin.bmp |grep -i depth=20
| reports...
| Depth: 8 bits
|
|
| I also have an unrelated question of how to modify the above command to a=
| llow the aspect ratio to change so the entire original image is jamed int=
| o the new geometry.
|
This is a known problem which I reported before.
That is IM generally outputs 8 or 16 bits to most file formats,
Regardless of if that format can handle other 'depths', with depth
picking between those formats.
It is even worse with a format like the NetPBM image file formats,
as images in these formats don't even have to correspond to a specific
'depth' but can in fact use any MaxRGB limit, and not just 2^depth-1
See IM Examples, Future Proposals,
Specify the exact depth for specific output formats
http://www.imagemagick.org/Usage/bugs/future/#quality
Of course it is only a proposal, unless someone is willing to
implement changes to the file format code, it probably will not happen.
I just updated the above proposal, though it may take a day or so to
appear, so I'll included the full proposal here, for any programmer that
like to work on it.
=======8<--------
Specify the exact depth for specific output formats
At this time depth is generally restricted to 8 or 16 depending on the
compile time Q-level of your IM installation. That is setting of
"-depth 4" only results in 8 bit images, not 4 bit images. Of course
that is only valid if the image format and IM even allows the use of
'depths' for that image format.
These depth/quantium restriction is becoming a problem for many image
formats such as NetPBM, TXT (IM pixel enumeration), BMP, TIFF...
etc..
Actually instead of "-depth', prehaps we can specify an exact
"-quantum" for text image formats such as TXT: PGM: PPM: all of
which should allow you to specify a different 'quantium' for its format.
Eg: convert -size 1x1000 gradient: -quantum 1000 t.pgm
===8<----
P2
1 1000
999
999 998 997 ... 3 2 1 0
===8<----
Where all image data values are in the 0 to 999 inclusive range.
If "-quantum" is unspecified (or reset using "+quantum"), it can
fallback set to a default of 2^depth (if it ever allows depths
other than 8 and 16!)
=======8<--------
Anthony Thyssen ( System Programmer ) <[EMAIL PROTECTED]>
-----------------------------------------------------------------------------
Two wrongs don't make a right, but three lefts do.
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Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/
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