ImageMagick – Replace the transparent part of a GIF with a solid colour

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I have a GIF file that has a transparent section. I want to replace that with just plain white (or some other colour), so that there is no transparent parts. Can I do this on the command line with ImaageMagick? I'm OK if the image has to change from a .gif to something else. I tried to convert it to a jpg and the tramsparent parts were black. Is there a way to customize that?

I'm using ImageMagick on Ubuntu 9.10 Karmic Koala

Best Answer

You can do this using the 'convert' binary that comes with imagemagick.

convert myimage.gif -alpha off myimage.gif

Read about setting it to a custom color here: http://www.imagemagick.org/Usage/formats/#gif_trans

Related Solutions

Using GraphicsMagick or ImageMagick, how to replace transparency with a fill colour

Using GraphicsMagick, -background color -extent 0x0 should be able to replace the first two steps in your process (for ImageMagick, it'd be -mosaic instead of -extent). I'm not sure about the third step, but it sounds like you're just running +matte on the image from the first two steps, so the final call would look something like this:

gm convert -background color -extent 0x0 +matte src.png dst.png

or for ImageMagick,

convert src.png -background color -mosaic +matte dst.png

Trimming exterior empty space with ImageMagick does not work on scanned documents

You can use -shave and simply shave off the edges and then use the logic you use afterwards to process accordingly.

Note: The amount you shave off (e.g. the argument after "-shave" 40x40 or 10x10, etc. ) is important so be sure to test thoroughly to ensure this setting works universally in your environment for your images.

Example Logic

@ECHO ON

SET Convert="C:\Program Files\ImageMagick\Convert.exe"
%convert% C:\Folder\Circle.jpg -shave 40x40 C:\Folder\ShavedCircle.jpg
<The rest of your logic against C:\Folder\ShavedCircle.jpg now>

Before

After

Further Resources

Shave, removing edges from a image

The reverse of the "-border" or "-frame" operators, is "-shave", which if given the same arguments, will remove the space added by these commands.

The main thing to keep in mind about these three operators is that they add and remove space on opposite sides of the images, not just one side, or adjacent sides.

If you want to only remove one edge of an image, then you will need to use the "-chop" operator instead. (See the Chop Examples below).

As before all the operators "-border", "-frame", and "-shave", only effect the real image on the virtual canvas and not the virtual canvas itself.

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