ImagePlugin dependency on CPAN:Graphics::Magick

Hi!

The ImagePlugin has a dependency on CPAN:Graphics::Magick. However this CPAN module seems to be non-exisiting, so am I am unable to get this plugin to work. The reason for wanting the ImagePlugin is that it is recommended for the PersonalInfoAddOn.

Does anyone have suggestions for how to proceed?

-- AtleBriskemyr - 21 Apr 2009

I'm not sure, but I believe the plugin can also use CPAN:Image::Magick if you set $TWiki::cfg{ImagePlugin}{Impl} = "Image::Magick". I don't have access to the code at the moment so can't be sure, but if you know Perl then you should be able to look in the code and find out.

-- AndrewJones - 21 Apr 2009

ImagePlugin needs either CPAN:Image::Magick or GraphicsMagick. Might be an error in the DEPENDENCIES. But I am pretty sure you can't express this either-or in them anyway. Did not know graphicsmagick is not on cpan :/

-- MichaelDaum - 21 Apr 2009

Is a question really answered if the only responses are along the lines of, "Huh. I didn't know that didn't work?" I've been trying for almost two years to get PersonalInfoAddOn working with TW/Foswiki. All of the responses to my and others' queries have basically been, "gee, that's difficult." If an important functionality depends on a successful installation/configuration of some other bit of code, shouldn't a serious effort be made to either eliminate that dependency or make sure that it can be installed by reasonable means?

Thank you

-- DavidWolfe - 21 Apr 2009

Unfortunately some of the dependencies will vary by platform and version of the upstream utilities used by the plugin. In this case, the bulk of the tools for image manipulation come from an external package. A number of the Foswiki plugins provide the "glue" to an external application, and "eliminating the dependency" would actually eliminate core functionality behind the plugin and/or the reason for the plugin to exist in the first place.

I do agree that the documentation could be much clearer for this plugin's dependencies. I don't have this plugin installed, but if it is at all similar to the ImageGalleryPlugin, I suspect that the plugin can use either ImageMagick, or it's fork, GraphicsMagick. At one time PerlMagick was installed using CPAN, but it appears that both now can install the perl modules as part of the main package distribution.

• The GraphicsMagick version of PerlMagick is installed as part of the GraphicsMagick distribution.
• The ImageMagick version of PerlMagick can be installed either from CPAN or as part of the ImageMagick distribution.

This all appears to vary based upon the OS and distribution in use. Detailed installation instructions may be a bit beyond what the plugin can easily document. For example, with Gentoo Linux, PerlMagic is installed automatically if ImageMagick is installed with the "perl" use flag configured, and GraphicsMagick is not in the distribution. And with Ubuntu Linux, perlmagick is a separate package installed with apt-get. If your distribution provides PerlMagick through its own package manager, then installing it via CPAN is probably not the correct solution.

So other than improving the documentation, in this case I'm not sure what the plugin can do to simplify all this. Given the variety of ways that PerlMagick can be installed, it would probably be best if if the plugin not try to install the dependencies via the installer. I'll open a task to request the documentation be updated.

-- GeorgeClark - 22 Apr 2009

I may be missing something, but it seems to me that both PersonalInfoAddOn and ImageGalleryPlugin both use ImageMagick/GraphicsMagick for the purpose of displaying images. Since HTML can already display images with control over sizing and arrangement, why are those external packages needed? Thank you

-- DavidWolfe - 22 Apr 2009

Image sizing in the browser means that the original large image has to be downloaded to the browser first. Also the capabilities of the browser to scale, crop, etc. can vary based upon the browser. Think handheld Use of ImageMagick allows resizing to thumbnail on the server, saving the bandwidth to the client. Also, at least with ImageGalleryPlugin, the thumbnail and intermediate sized images are cached on the server, so that the conversion is only done once.

-- GeorgeClark - 22 Apr 2009

Thanks to George for guiding me on how to install the PerlMagic (including ImageMagick) on Ubuntu systems. Now I was able to install (no dependency errors ) and test the plugin without any trouble.

-- AtleBriskemyr - 23 Apr 2009

A clarification: ImagePlugin is not required for PersonalInfoAddOn. The plugin offers an extra enhancement to create and show thumbnails instead of the large images users may upload. If ImagePlugin is not installed the addon will function normally.

-- ArthurClemens - 23 Apr 2009