On Sunday 20 July 2008, Raphaël Quinet wrote: > On Sun, 20 Jul 2008 21:22:11 +1000, Snake Arsenic <[EMAIL PROTECTED]> 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 > [email protected] > https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer _______________________________________________ Gimp-developer mailing list [email protected] https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-developer
