I have an image that has just letters on it withwant to make a transparent background.progress bar made of text! I was thinking that ashave two images: One with the text in gray, the other coloured:

As my game is loading that these, I want the letters couldto "fill up" with a certain color. So they:

They would start out gray and, then starting from the left each letter starts to get redfill in.
I was thinking aboutof overlaying a transparent rectangle over itthe gray image, andthen stretching the transparent rectangle based onto match the progress. But then the background also will turn red andbe coloured too. I want just the lettersonly the letters to be red. Any ideascoloured!
How can I do this?