@Weasel Op and Balthasar: I'm not sure, but I think you guys might have misunderstood what I mean. I always convert to RGB before I edit the image, but after you convert it to indexed the only editing to the colours you can do is to re-arrange the colours. GIMP doesn't know that the magenta and the green are supposed to be at 255 and 254 respectively, and places them randomly somewhere in the palette. So you have to rearrange the colourmap and manually put them in that position.
AFAIK it's not possible to change a colour after it's been indexed. By this I mean that if I had a palette of 256 colours, and colour #45 was 0xff0000 (red), but I wanted to change it to 0x0000ff (blue), the only way to do this is by converting the image to RGB, change my selected colour to 0x0000ff, place a pixel of that colour on the canvas, convert the image back to indexed and then rearrange the palette, moving my blue colour to position #45.
That's a pretty convoluted way of adding a colour. I want to be able to manually add 0x0000ff while still in indexed mode, and then drag it to position #45.
Something else I noticed with GIMP is that even if you specify you want an indexed palette of 256 colours, it will only create a palette with at most the number of colours on the canvas. So if you have only used 25 colours to create your sprite, the palette GIMP will create is going to be 25 colours. The workaround I've been using thus far is to paint a gradient on the canvas somewhere before converting to indexed so that GIMP will fill in the other 231 colour slots with dummy colours. I also have to place a 0x00ff00 pixel and a 0xff00ff pixel somewhere on the canvas so that GIMP will create those colours in the palette, and then rearrange the palette after it's indexed to make sure that the transparent colours are added properly.
In short, all of this is a huge pain in the...well you know. ^_^
Please tell me, guys, that the way I'm doing it is not the easiest way to do this in GIMP!!!
Well, yeah, you're doing it the hard way. At the risk of repeating myself, the steps to take when using GIMP (as I do it; I'm always looking for something even easier) are:
1. Original image -
select all - copy - create new image from clipboard (default mode is RGB)
2. Using the
Select by color tool,
Remove all magneta and neon green (the transparent colors) from the image. Sometimes you have to do this a few times as there are sometimes some near-magneta stragglers. You should have now an image with a transparent background. If your background isn't transparent, you have to go back and repeat step one, making sure to
Edit -select all before copying...
3. Now you can do anything you want with your image, even add layers (being sure to use transparent background) Remember that you can use the (control-Z) key to go back to the previous step, or even several steps back at
any point, so if you get almost finished and decide you want to add something, you can step back to this point to change it. You can also save a work copy of this as an .xcf (Gimp) image at this point in case major changes are necessary later...
Image - merge visible layers at the end of the process, before going to the next step.
4.
Select all - copy (afterwards, I have to click the cursor off-screen to make the highlight go off)
5.
Image - mode - indexed Civ requires 256 colors, mine gives me 255
6.
Dockable Dialogs - colormap at this point I click on the last color on the colormap then click the "+" (add) sign to make it 256 colors. If the colormap has too few colors on it, then I click the "+" button as many times as it takes to get to 256 colors. Then I right-click on the second to last color and select
edit and I get a dialogue box:
notice that the magneta (00ff00) and neon green (ff00ff) colors were saved in this dialogue along with my other most recently used colors. This helps, because I can just click on the green one before moving on and editing the last color on the colormap the same way.
7. Before I close the colormap, I click again on the last color (now magneta) to establish it as the foreground color; now I use my Select by color tool again to highlight the transparent areas in the picture and
Edit - fill with foreground color (I use the hotkey: Ctrl -"," these days)
8. Now remember the copy of the image we made in step 4? That's still on the clipboard, so we can go
Edit - paste to ensure that all colors are as we want them (this will convert any neon green straggler back to its proper color)
9. Now save as
Image name.pcx and you're done.
If you follow those steps, there's no reason you should have to move colors around on the colormap
ever, that I can think of.... Sorry if I've repeated alot that you already know, I'm just trying to help you get away from what you describe as a hellish way of doing the same thing....
For the noobs who may have tripped over this: there is a much clearer tutorial for this that Varwnos wrote >
here<