On Sunday 20 July 2008, Raphaël Quinet wrote:> 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. [...]> Hi!Going beyond all of Raphael's excelent remarks, I still see some issues here :1) The ability to "ciew teh layer sans transparency" and "edit the alpha channel as if it where any other channel" is provided in GIMP - you copy the alpha channel to the layer's mask, and edit it (the layer's mask). 2) The request indeed points a thing: GIMP _has_ the ability to set each channel "visible" or not - in the layers channel. If the <image> channel is disabled in the channels dialog, channel cvaleus are considere as zero for all display operations. However, setting the alpha channel to zero in this way - which is what gimp does -is useless - you just can't see anything in the image, as it is rendered with alpha = 0 for all layers.I'd suggest that when the alpha channekll si disabled in the channel dialog, image is rendered with alpha =1.0 (255) insetead. That would: a) enable the feature thought when the ability to run channel'son and off was included; b) Make gimp attend the requesterś (Snake) needs. Maybe the bug request should be chanegd accordingly? Moreover - I really think it is a more usefull (even if seldom used) behavior for disabling the alpha. What do you say of doing it? > I think that it would be a big mistake to use the alpha channel for> anything else than transparency. I assume that you are asking for> this because you have some program (I don't know which one) that is> incorrectly using the alpha channel to store bump map information> or something else that is not related to transparency. It is> likely that this program doesn't use a file format that supports> layers or independent channels, so its authors of have decided to> hijack the alpha channel in some existing file format. > The correct way to solve this problem is to use layers instead of> abusing the alpha channel (or maybe additional channels, but I> think that 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 map layer, specular map layer or whatever else you are> working on.>> So instead of extending the mistakes done by the authors of some> other software, it would be much better to know what file format> has been subverted, 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 list> Gimp-developer@xxxxxxxxxxxxxxxxxxxxxx> https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer _______________________________________________Gimp-developer mailing listGimp-developer@xxxxxxxxxxxxxxxxxxxxxxxxxxx://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
