"Peter Pimley" on wrote...
|
| Hi Anthony, Thanks for your information.
|
| > By default IM treats transparent and semi-transparent colors
| > as just another color. However two years ago a change was
| > may so as to make full-transparent any-color mean the same
| > thing. EG transparent-black is also transparnet white.
|
| OK, that's what I'm looking for :)
|
| > See IM Examples, Quantization and transparency.
| > http://www.imagemagick.org/Usage/quantize/#color_trans
|
| Yes, that's concrete proof of what you said. It's doing exactly what I
| want, but with PNGs.
|
| > As for TGA. No one has reported in the list or forums what
| > IM does for these images, and if or how it handles 'indexed TGA'.
|
| My experience is that when IM saves a TGA, it saves one of the
| following:
|
| 1) 32 bit
| 2) 24 bit
| 3) 8 bit indecies into a 24 bit palette
|
| Taking alpha_gradient.png from the example page you gave me:
|
| $ convert alpha_gradient.png alpha_gradient.tga
| produces a 32 bit TGA which looks exactly like the PNG
|
| $ convert alpha_gradient.png +matte alpha_gradient.tga
| produces a 24 bit TGA, discarding the alpha channel
|
| $convert alpha_gradient.png -colors 256 alpha_gradient.tga
| produces a 8 bit index / 24 bit palette TGA. The image is opaque
|
| Up until now, one of the three above has always been what I've needed,
| so I've never had a problem before. But what I'm trying to persuade it
| to do now is to save 8 bit indexed into a 32 bit palette. I've been
| reading through the TGA format spec
| http://www.dca.fee.unicamp.br/~martino/disciplinas/ea978/tgaffs.pdf and
| it sounds like it ought to be possible (see "Color Map Specification").
| Do you think that's worthy of a bug report / feature request?
|
| If not, what I'll end up doing is the following:
|
| convert {source} -colors 256 -type TrueColor output.tga
| (which produces a 32 bit TGA with alpha values, up to 256 unique 32-bit
| values in the image)
|
| ... and then write my own code to move the colors from the image into
| the palette.
|
| Do you have any opinions?
|
You can always put in a BUG report/ feature request on the IM bugs
forum. Detail the above in that request.
However all of the developers are always very busy, and a new feature is
often pushed to the end of a very very long 'to do' list.
It may be better for you to try to look at the source and see if you can
add it yourself.
I have no idea who wrote the TGA code, probably was done quite a long
time ago. 8-bit indexed TGA with 32 colors is probably not something
they really thought about.
First however try to find out if it is actually posible. A link to an
example of what is actually wanted would also help.
Im must not only be able to write it, but it needs to read it too.
Anthony Thyssen ( System Programmer ) <[EMAIL PROTECTED]>
-----------------------------------------------------------------------------
UNIX is the spawn of the devil,
why he even has his deamons running the thing! -- Anthony Thyssen
-----------------------------------------------------------------------------
Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/
_______________________________________________
Magick-users mailing list
[email protected]
http://studio.imagemagick.org/mailman/listinfo/magick-users
