
In order to follow the tutorial, you must have the newest version of GAP, currently 2.2.0. I've also posted the background/flash xcf files on my deviantart account (Fencepost's DA Account), so that you can download and follow along step by step.
This tutorial has been re-written from the original version. The original tutorial assumed a working knowledge of GAP; however, this tutorial will be explained so that even a beginner to GIMP can follow. That being said, I've tried to include as many screenshots as possible to make the steps much more clear. To keep the tutorial a bit more compact, I haven't included a screenshot for everything. For those steps without an image, I will describe the steps in great detail and will use the following format for menu locations: Select | Save to Channel means that you will go to the "Select" menu and choose the "Save to Channel" option.
However, if you don't have GAP or would like to try a version that does not require GAP, please check out this tutorial: http://www.gimptalk....99-1.html#38596
So, without further ado, let's begin.
[*]Create an animation folder somewhere on your hard drive and store both the background_000001.xcf and flash.xcf files in it. This is to help with housekeeping.
[*]Open up the background_000001.xcf and flash.xcf files in GIMP.
The background file will look like this:

[*]With the text layer highlighted, right click on it and choose "Alpha to Selection." This will select the outline of the text, like so:

I've outlined the text in red so you can see what the Alpha to Selection is supposed to look like. Yours won't be red, but it will be surrounded by the "marching ants."
[*]Now, we need to convert the selection to a channel. I won't describe what a channel is, but we will be converting it back into a selection/mask later on. This is a very important step. Follow it
closely.

This is where GIMP stores the channel. Note the name that is automatically assigned to it by GIMP. We will need this name later.

Now that we have some of the basic setup steps out of the way, let's move on.
[*]Go to Video | Duplicate Frames and set your settings like so:

This will automatically create a total of 20 xcf files in your file numbered sequentially. Your original
background layer (background_000001.xcf) will keep its name and it's really the only one we'll be working with directly. We'll let GAP automatically modify the other 19 frames through various menus.
If you take a quick peek within your animation folder (you did create a folder, didn't you?) you see 20 files named "background_00000xx" with the x's representing the numbers.
If you're new to GAP, you might be wondering why we did the Duplicate Frames step and why did I choose the number 19. An animation is nothing more than slight modifications from one frame to the next. Since this is a basic animation, I want to use the background and text layer over and over again, so I tell GAP to duplicate it "x" number of times (or in this case 19 times). Why 19? It's really an arbitrary choice. I first used 9 when experimenting, but the animation was a little fast for my taste. By adding more frames, the highlight was allowed to take longer to complete than if I had stuck with my original number of frames (9). Ok, enough with the GAP theory, let's move on.
Now, it's time to begin the animation steps. Moving the highlight part within GAP is really easy, but we only want to limit the highlight to the text. This will take some additional steps, which may seem difficult at first, but once you get the hang of it, you'll be a pro!
[*]From the Background xcf file, Go to Video | Move Path....
The following window will open up:

Follow the graphic and change the settings as follows (I will not be explaining what each of these settings do, just follow my lead for now):
[*] A: "None"
[*] B: "Screen"
[*] C: "Left Top"
[*] D: Place a check mark within to the "Instant Apply" box
[*] E1: Set X to 215. This will place the highlight to the left of the text.
[*] F1: Click "Add Point." This tells GAP to lock in the location set in step E1.
[*] E2: Set X to 450.
[*] F2: Click "Add Point."
Guess what? We've actually told GAP to move the highlight across the signature. Let's try it out and see.
[*]G: Click "Anim Preview" The following window will open. Change the settings like so:

[*]Select "OK" and choose "Play/Stop" to watch the highlight move across the signature. It looks pretty good, but we want to limit it to the text only.
[*]Close the animation preview window AND the new GIMP file named "Untitled". When it asks to if you want to save, Choose "Don't Save. We don't need it.
Now you'll be back to the "Move Path" window.
[*]H: Click "OK" What the OK button does is modify each of the background_0000xx layers.
Here's the fun part. We need to limit the highlight to the text. To accomplish this, we've got to be a bit creative. Since we're GIMP users, we know that creativity is one of our strong points!
[*]Go to Video | Frames Modify and choose the following:

Leave the rest of the settings as they are and, in the blank, type in the name of the channel exactly as GIMP named it. If you can't remember, go back to your "Channels" dialog and copy/paste the name in the blank. choose OK. What we're going to do here, is load the channel we created earlier and add it to each of the frames. The rest of the settings tell GAP that Layer Pattern "0" is the top layer (or in our case, the highlight layer").
[*]Now, Go to Video | Frames Modify and make the following choice:

Here we will add a layer mask from the selection created by the channel in the step above and use the mask to hide the highlight outside of the text.
[*]Now Go to Video | Frames to Image and Choose OK. This converts all the background_0000xx.xcf files into one image.
A new window will open up.
[*]Go to Filters | Animation | Playback and play your new creation.
Looks good, doesn't it?
Here's the result:

[*]Now, go to Filters | Animation | Optimize for GIF.
[*]Save as an animated GIF
[*]Show of your new creation to all your friends (and maybe even your enemies!)
Well, I hope you enjoyed this tutorial. Comments and Criticisms are welcome.
Happy GIMP-ing!
Art
EDIT: For all you really curious types, you may have noticed that in the Frames Modify section, there are two choices under the Layer Masks menu for applying a mask from another layer (either above or below) to the current layers. You may wonder why I didn't choose this step instead of the creating a channel selection and applying the channel selection as a mask later on. That's a very good question, but I have an even better answer! I did try it. Only one problem, GAP decided to actually move the position of the mask up and to the right by several pixels. In fact, it wasn't over top of the original text at all. So, here I thought I had the perfect solution, but GAP didn't think so. At least I figured out a work around!

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