On Sun, 20 Jul 2008 21:22:11 +1000, Snake Arsenic <snakearsenic@xxxxxxxxx> wrote:> Okay I made a feature request at > http://bugzilla.gnome.org/show_bug.cgi?id=543810 but it's missing a > solution that will not remove any functionality. [...] I think that it would be a big mistake to use the alpha channel foranything else than transparency. I assume that you are asking for thisbecause you have some program (I don't know which one) that isincorrectly using the alpha channel to store bump map information orsomething else that is not related to transparency. It is likely thatthis program doesn't use a file format that supports layers or independent channels, so its authors of have decided to hijack thealpha channel in some existing file format. The correct way to solve this problem is to use layers instead ofabusing the alpha channel (or maybe additional channels, but I thinkthat using layers would be more convenient in this case). With layers,it is very easy to toggle the visibility of the image or the bump maplayer, specular map layer or whatever else you are working on. So instead of extending the mistakes done by the authors of some othersoftware, it would be much better to know what file format has beensubverted, and to perform the conversion in the file plug-in:* When the plug-in loads a file that uses this strange format, it would convert the alpha channel into a layer and mark that layer (using a special name like the GIF plug-in does for animations, because that can be edited easily by the user if necessary).* You would then be free to edit the image in GIMP and modify the layer containing what should be visible or the layer containing the bump map.* When saving the file, the plug-in would detect that some layers have a special name and would then combine these layers in a way that can be read by whatever other program you are using. So I suggest that you:1) Identify what file formats need some special treatment.2) Check if there is a way to detect what files using that format are special, so that we do not have to ask the user every time if a file using that file format should be read in the intended way (alpha channel = transparency) or in the non-standard way (bump map).3) Suggest improvements to the corresponding file plug-ins, instead of requesting major changes in the GIMP core. -Raphaël_______________________________________________Gimp-developer mailing listGimp-developer@xxxxxxxxxxxxxxxxxxxxxxxxxxx://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
