forced palette for RGBA images
Steve.Lime at DNR.STATE.MN.US
Thu Dec 6 13:00:06 EST 2007
I was just wondering if there were a case where building/configuring MapServer or MapScript
could bomb with libpng functions included, but since we already seem to detect it then that
shouldn't be a problem.
>>> On 12/6/2007 at 11:47 AM, in message
<d2b988930712060947y187df964oc666000f744a5ad4 at mail.gmail.com>, thomas bonfort
<thomas.bonfort at GMAIL.COM> wrote:
> Not that I know of appart from some questionnable choices in libpng of
> aborting compilation if setjmp.h was already included beforehand (even
> if it's properly #ifdef'd)
> are you thinking of something in particular?
> On Dec 6, 2007 6:07 PM, Steve Lime <Steve.Lime at dnr.state.mn.us> wrote:
>> Sounds cool. Any configuration issues related to libpng?
>> >>> On 12/6/2007 at 10:07 AM, in message
>> <d2b988930712060807n281f8850t386bd85182bd1a22 at mail.gmail.com>, thomas bonfort
>> <thomas.bonfort at GMAIL.COM> wrote:
>> > hello list,
>> > I've added the possiblity to force a color palette for RGBA images. As
>> > gd does not support this kind of images, I had to resort to directly
>> > use libpng functions for the actual saving of the file.
>> > The steps needed to actually use this would be:
>> > - create a 24 bit rgba image representative of a typical image that
>> > would be produced
>> > - use an external program to create an rgba paletted version of the
>> > image (pngquant, pngnq, photoshop...)
>> > - extract the palette from the created image and save the values in
>> > the form r,g,b,a in a text file (one per line)
>> > - use palette_force and palette formatoptions in the outputformat block.
>> > This is rather complicated, but usefull on production setups to
>> > minimize image size when using clients that overlay layers (eg
>> > openlayers).
>> > There are still a few quirks I'd have to work on before the code is
>> > robust enough for inclusion in the trunk, so I'd like to know if this
>> > is a feature we'd definitely like to have before putting too much
>> > effort into that.
>> > cheers,
>> > thomas
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