[MacPorts] #55184: libsdl2_image: Request for variant or change to default build

[MacPorts]

#55184: libsdl2_image: Request for variant or change to default build
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 Reporter:  jdolan               |      Owner:
     Type:  request              |     Status:  new
 Priority:  Normal               |  Milestone:
Component:  ports                |    Version:  2.4.2
 Keywords:  sdl sdl2 sdl2_image  |       Port:  libsdl2_image
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 By default, on OS X, SDL2_image relies on Apple's ImageIO backend to load
 most image formats. Indeed, this is how SDL2_image is currently compiled
 via the Portfile. Unfortunately, ImageIO is not without significant
 problems that can break certain applications, e.g.:

 https://stackoverflow.com/questions/46975125/sdl2-pre-multiplying-alpha-
 channel-when-loading-surface-on-os-x

 The SDL2_image port already depends on libpng, jpeg, and tiff. Using these
 backends produces uniform behavior that is consistent with other
 platforms. In my opinion, it would make sense to switch off the ImageIO
 backend, and compile SDL2_image with libpng, libjpeg and libtiff support
 instead. Or, alternatively, this option could be made available as a
 variant.

 Here is the configure line that produced the best working result on my
 machine. Note that I had to disable all of the dynamic library loading
 backends, as they fail for some reason:

     ./configure --prefix=/opt/local \
         --disable-imageio \
         --disable-png-shared \
         --disable-tif-shared \
         --disable-jpg-shared \
         --disable-webp-shared

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Ticket URL: <https://trac.macports.org/ticket/55184>
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