mirror of https://github.com/GNOME/gimp.git
68 lines
2.0 KiB
Plaintext
68 lines
2.0 KiB
Plaintext
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Gimp Pixmap Brush File Format
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The current format for gpb files, the pixmap
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bnrush format is very simple. What it essentially
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boils down to is a greyscale gbr (gimp brush) and
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a rgb pat (gimp pattern) concatented into the same file.
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The gbr is first, and is used for the greyscale mask for
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the brush. The pat is second and is used for the rgb info in
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the file.
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The name and spacing info for the greyscale portion
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is used for the name and spacing of the pixmap
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brush.
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The greyscale mask and the rgb data need to be of
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the same height and width.
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The easiest way to create a gpb file is to use the gpb plug-in.
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Create an RGBA image, and save as a .gpb file.
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(Before that plug-in was written, the easiest way to
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create gpbs was:
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1. Create a rgb image of some sort. The best
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images seem to be something on a black background,
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but thats not required.
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2. Generate a mask for all the parts of the image
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that should be transparent in the final product. There
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are several ways to do this but quickmask, or select
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by color, selection to channel seem to be a good way to
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do it. This mask needs to be greyscale. So I usually
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make it a selection, and then use "save selection
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as channel"
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3. Take that mask, select all, and cut it. Then
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open a new greyscale image, and paste it into the
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image. This is the easiest way to insure the images
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are the same size and are aligned. The white portions
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of this image will be what is opaque in the pixmap
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brush.
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Take the above mask, and save it as a .gbr file.
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It doesnt need to be in the brushes dir.
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5. Take the original rgb image, remove any mask layers,
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and flatten the image. Setting background color to black
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and flattening to a black background seems to work
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a little better.
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Take this image, and save it as a .pat file. This does
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not need to be in the patterns directory.
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6. Go to a shell, and concatenate the files together
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into a .gpb. Ie, for a mask named foo.gbr, and a
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rgb pat name foo.pat:
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cat foo.gbr foo.pat > foo.gpb
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7. Copy that foo.gpb to your brushes dir
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)
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Adrian Likins
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aug 18, 1999
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