Nick Cummings on wrote...
| 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
|
That only converts perfectly white text to transparency.
What you want to do is use the 'grey scale' black text on white
background as a 'transparency mask' for some other color, such as
a transparent mask of a pure black image...
EG:
cpnvert image_in.png +matte \
\( +clone -fill black -colorize 100% \) \
+swap -compose CopyOpacity -composite \
image_out.png
The first line ensures the initial image (mask) is read in and fully
opaque.
The second creates a pure black image the same size as the mask.
The third uses the first image as a transparency mask for the second
and finally we output the result.
See.. IM Examples..
Using Masks with Images
http://www.cit.gu.edu.au/~anthony/graphics/imagick6/channels/#masks
Using Compose Mask to Limit the Composed Area
http://www.cit.gu.edu.au/~anthony/graphics/imagick6/compose/#mask
Anthony Thyssen ( System Programmer ) <[EMAIL PROTECTED]>
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..., the kind of rain that is merely a upright sea with slots in it.
-- Terry Pratchett - ``Truckers''
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Anthony's Home is his Castle http://www.cit.gu.edu.au/~anthony/
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