CODEWITHSUNDEEP
imagemagick
Chris White
Chris White

Reputation: 953

ImageMagick argument to specify output format

I'm using ImageMagick programmatically to apply some user-defined transformations to an image. The script I'm using spawns a new process and runs ImageMagick with arguments similar to:

convert /tmp/source -resize 100x /tmp/transformed

And then it reads the transformed image back from /tmp/transformed. I'd like to add the option to convert the image to another image format, but from looking at the IM docs for a while, the only way I can see of doing that is to append the output destination with .<ext>, like this:

convert /tmp/source -resize 100x /tmp/transformed.png

Is there another way? The easiest way for me to do this with the pre-existing script is to supply an argument, but I can't find it. Something like:

convert /tmp/source -resize 100x -format png /tmp/transformed

Is this possible? Or am I stuck with having to append the extension to the output destination?

Upvotes: 6

Views: 7041

Answers (2)

Mark Setchell
Mark Setchell

Reputation: 207465

I'm not sure what your aversion is for appending a suffix, but another alternative to Fred's excellent suggestions is to use a "format specifier" prefix, which would leave your base filename unchanged - if that is what you are trying to achieve.

convert Image -resize 100x PNG:/tmp/transformed/Image

Substitute PNG: with GIF:, JPEG: etc to suit.

Upvotes: 13

fmw42
fmw42

Reputation: 53081

-format png is used in mogrify and not convert as I understand it. You need to specify the suffix for the input and the desired suffix for the output in the input and output filenames.

convert /tmp/source.suffx -resize 100x /tmp/transformed.png

assuming png is the desired output format.

Perhaps I misunderstand what you want. If so, please clarify. Are the suffixes in the source and transformed variables? If so, you can use IM to separate the source filename from its suffix using %t and %e in string formats. But for the output, you would have to parse that using your file system. See http://www.imagemagick.org/script/escape.php

Alternately, use mogrify which supports -format png

mogrify -format png -resize 100x *.suffix

That will take every file in the input directory with suffix .suffix and convert that to png. However, I would suggest you create a new directory to hold all your output images, since as it is, it will overwrite your input files. You would then need to add -path path2/newdirectory to the command above. see http://www.imagemagick.org/Usage/basics/#mogrify

What are the actual filenames associates with source and destination? Are these just variable for the real filenames?

Upvotes: 4

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