I tried posting this on the ImageMagick Studio forum, but I didn't get any responses. I'm hoping to have better luck here. My apologies to those who are seeing this for the second time.
I'm trying to make some images of equations I have written in LaTeX, using my Linux system. I want the equations to be a with black text on a transparent background. I originally tried a program called eqe (that apparently uses ImageMagick internally), but I found that if I tried producing a PNG of black text on a transparent background, it appeared to have white-ish bits at the edges of the text if placed on a dark background. I gather that this is due to anti-aliasing. What I'm currently trying to do is use the ImageMagick (6.0.6) command line tool "convert" in Linux to take a PNG image of black text on a white background and produce a PNG of black text on a transparent background. If I simply apply the command convert -transparent white image_in.png image_out.png I get the same result as with eqe, white-ish bits around the text. If I produce an image of the equation without anti-aliasing, I can convert it without getting the white bits, but the resulting text doesn't look very good without the anti-aliasing. So, I'd like to have both anti-aliasing and transparency. I assume that anti-aliasing sets pixels near the text to slightly gray values and that "convert -transparent white" only sets pixels that are completely white to being transparent. I'm not very knowledgeable about image manipulation, but my guess is that I can achieve a decent looking image with both anti-aliasing and transparency by applying an operation to the black text on white background that will set the transparency of each pixel according to the gray-scale value, with black being totally opaque and white being totally transparent. convert appears to be quite powerful, and I think it is possible to do what I want, but I don't quite understand how. After reading the man page for ImageMagick and convert, I tried the command convert -channel alpha -fx 'Transparent*(r+g+b)/3.0' image_in.png image_out.png but this doesn't seem to do the right thing. Actually, it doesn't seem to do anything at all. Any tips on how to do what I want? I'd take either the correct way to use -fx to do this or any other tips. I must admit that I couldn't really understand the usage of the -fx option from the man page. Thanks, Nick __________________________________________________ Do You Yahoo!? Tired of spam? Yahoo! Mail has the best spam protection around http://mail.yahoo.com _______________________________________________ Magick-users mailing list [email protected] http://studio.imagemagick.org/mailman/listinfo/magick-users
