Legacy ImageMagick Discussions Archive

Hello,
I want to use imagemagick without GPL problems. But I need the pdf reading feature. How I unterstand I could build imagemagick with --without-gslib to avoid GPL problems. Is that correct? Where do I need to define this flag in Visual Studio?

Thanks for your help!
chris

The Windows version of ImageMagick does not build against Ghostscript. Instead it sees if the Ghostscript Dll's are installed on the system and if so only then does it utilize Ghostscript to interpret PS / PDF.

Thanks for the answer.

Are you sure that this does not hurt the GPL ? How I understood only commandline calling is conform to GPL(if the calling programm is not GPL conform)?

ImageMagick is not GPL. It is Apache 2. You can add functionality to ImageMagick by interfacing to external libraries and utilities. Each of these utilities have their own licenses and conditions. Its up to you to decide which licenses you are willing to adhere to.

How do you call ghostscript?

I found an interesting part in the GPL FAQ http://www.gnu.org/licenses/gpl-faq.html:

Can I release a non-free program that's designed to load a GPL-covered plug-in?
It depends on how the program invokes its plug-ins. For instance, if the program uses only simple fork and exec to invoke and communicate with plug-ins, then the plug-ins are separate programs, so the license of the plug-in makes no requirements about the main program.

If the program dynamically links plug-ins, and they make function calls to each other and share data structures, we believe they form a single program, which must be treated as an extension of both the main program and the plug-ins. In order to use the GPL-covered plug-ins, the main program must be released under the GPL or a GPL-compatible free software license, and that the terms of the GPL must be followed when the main program is distributed for use with these plug-ins.

If the program dynamically links plug-ins, but the communication between them is limited to invoking the ‘main’ function of the plug-in with some options and waiting for it to return, that is a borderline case.

Using shared memory to communicate with complex data structures is pretty much equivalent to dynamic linking.

See also the question I am writing free software that uses a non-free library.

As mentioned, we look for the Ghostscript DLL's and if they exist we utilize them. If that taints the GPL license, its up to you to research and decide.