SDL_Image patch for ILBM Amiga images

SDL Development
1

Hi all,

Here’s a patch for SDL_Image, adding support for classic Amiga ILBM formats:

  • fixes a small bug with stencil (images with a transparent color but no
    stencil/mask plane could not be read)
  • fixes colormap for EHB (“Extra Half Brite”) mode (these images have 6
    bitplanes, but the colormap only contains 32 colors. The second half of the
    colormap has to be a copy of the first one, with brightness divided by 2)
  • adds support for HAM (“Hold And Modify”) and HAM8 modes. These are
    converted to 24bits images.

Detailed information about these formats can be found on
http://netghost.narod.ru/gff/graphics/summary/iff.htm

The attached patch is a unidiff against SDL_Image version 1.2.3. ?I tried it
on 2 debian/testing systems (x86 and PPC), seems to work great. ?Please
contact me if this patch needs some work in order to be accepted.

Bye!

David.

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2

oups, I haven’t been carefull enough with my tests (endianness issue). This
version should work everywhere.
BTW is this the correct way to propose patches? I couldn’t find anything in
the web pages.

Bye

David.

Hi all,

Here’s a patch for SDL_Image, adding support for classic Amiga ILBM
formats: - fixes a small bug with stencil (images with a transparent color
but no stencil/mask plane could not be read)

  • fixes colormap for EHB (“Extra Half Brite”) mode (these images have 6
    bitplanes, but the colormap only contains 32 colors. The second half of the
    colormap has to be a copy of the first one, with brightness divided by 2)
  • adds support for HAM (“Hold And Modify”) and HAM8 modes. These are
    converted to 24bits images.

Detailed information about these formats can be found on
http://netghost.narod.ru/gff/graphics/summary/iff.htm

The attached patch is a unidiff against SDL_Image version 1.2.3. ?I tried
it on 2 debian/testing systems (x86 and PPC), seems to work great. ?Please
contact me if this patch needs some work in order to be accepted.

Bye!

David.
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