ImageMagick and OS X Lion trouble
On 10.8 I solved this issue with: brew install libtool –universal brew link libtool If you don’t know what brew is, visit https://github.com/mxcl/homebrew and its wiki.
imagemagick
Convert RGB to Grayscale in ImageMagick command-line
convert <img_in> -set colorspace Gray -separate -average <img_out> gives the best result for any image for me.
ImageMagick: Error while running convert: convert: unable to read font
Looks like you’re missing ghostscript. If you are using Homebrew you can install it via: $ brew install ghostscript
ImageMagick: scale JPEG image with a maximum file-size
To restrict the resulting image to a maximum file size, you can use the commandline parameter -define jpeg:extent=max_value, like this: convert original.jpeg -define jpeg:extent=300kb output.jpg convert original.jpeg -define jpeg:extent=300kb -scale 50% output.jpg convert original.jpeg -define jpeg:extent=300kb […other options…] output.jpg Note, this will not always work to match the exact size you wanted. You may have … Read more
How to execute ImageMagick to convert only the first page of the multipage PDF to JPEG?
If you are using a convert command line you can execute it with these parameters: convert source.pdf[0] output.jpeg Note that the page count of ImageMagick is 0-based. So [0] means ‘page 1’. To select, say the 4th page, you’d have to use [3]. This syntax does not only work for PDF input. It also works … Read more
What is the difference between ImageMagick and GraphicsMagick?
As with many things in life, different people have different ideas about what is best. If you ask a landscape photographer who wanders around in the rain in Scotland’s mountains which is the best camera in the world, he’s going to tell you a light-weight, weather-sealed camera. Ask a studio photographer, and he’ll tell you … Read more
How do I crop an animated gif using ImageMagick?
convert input.gif -coalesce -repage 0x0 -crop WxH+X+Y +repage output.gif Animated gifs are often optimised to save space, but imagemagick doesn’t seem to consider this when applying the crop command and treats each frame individually. -coalesce rebuilds the full frames. Other commands will take into consideration the offset information supplied in the original gif, so you … Read more
Converting GIF’s, PNG’s and JPG’s to .ICO files using Imagemagick
Add this option to convert: -background transparent However, keep in mind that your original image must actually have an alpha channel. PNGs may have an alpha channel, JPEGs do not.
Convert SVG to transparent PNG with antialiasing, using ImageMagick
Instead of -background transparent, use -background none. convert -background none in.svg out.png NOTE: The order of the arguments is important.
How do I modify a Homebrew formula?
Remove the existing version. $ brew rm imagemagick Edit the formula. $ brew edit imagemagick This will bring it up in an editor; make sure your $EDITOR variable is set to your preference (for me: TextMate) Change it, save it, try re-installing it. Because most installs use pouring/bottles to install a precompiled binary, you will … Read more