[CMake] FindImageMagick: Rewrite to support all utilities.

[Miguel A. Figueroa-Villanueva]

On 10/14/07, Alex Neundorf wrote:
> On Saturday 13 October 2007 07:17, Miguel A. Figueroa-Villanueva wrote:
> > Hello,
> >
> > I've been assigned the task of maintaining the ImageMagick find
> > module. As such, I made a rewrite to support the complete toolchain
> > (i.e., all command line executables) and would like to ask for user
> > feedback before committing the changes. The new module is attached for
> > reference.
> >
> > The pattern that I'm using for this find module comes up a few times,
> > for example FindLATEX could use it. Instead of hard-coding the tools
> > to search for I use the COMPONENTS argument in of the FIND_PACKAGE
> > command. For example, if I need ImageMagick's convert I would do:
> >
> > FIND_PACKAGE(ImageMagick COMPONENTS convert)
> >
> > If found the following variables will be set:
> >
> > #  ImageMagick_FOUND - TRUE if all components are found.
> > #  ImageMagick_EXECUTABLE_DIR - Full path to executables directory.
> > #  ImageMagick_<component>_FOUND - TRUE if <component> is found.
> > #  ImageMagick_<component>_EXECUTABLE - Full path to <component>
> > executable.
>
> Why do you use FIND_PATH() instead of FIND_PROGRAM() ?
> Then you wouldn't have to care for the different suffixes.

Something like this should work:

FIND_PROGRAM(ImageMagick_mogrify_EXECUTABLE mogrify ...)
GET_FILENAME_COMPONENT(ImageMagick_EXECUTABLE_DIR
       ImageMagick_mogrify_EXECUTABLE PATH
)

...

Then the only variable in the CACHE would be
ImageMagick_mogrify_EXECUTABLE instead of ImageMagick_EXECUTABLE_DIR.

Should I change ImageMagick_EXECUTABLE_DIR to ImageMagick_ROOT_DIR ??

Since I haven't had any objections I'll go ahead and commit with the
previous change (i.e., find_program thing above). Note also that I
would like to make the following additions:

- add XXX_EXECUTABLE_DIR to the variables in the readme.txt in the
Modules directory, unless it is recommended to use the XXX_ROOT_DIR
naming.

- create a macro in the same line of
FIND_PACKAGE_HANDLE_STANDARD_ARGS(...), and possibly in the same file,
that checks if all components are found to set the main variable:

FIND_PACKAGE_HANDLE_STANDARD_COMPONENTS(ImageMagick)

would basically do a:

# check if all components are found to set XXX_FOUND
SET(XXX_FOUND TRUE)
FOREACH (component ${XXX_FIND_COMPONENTS})
  IF (NOT XXX_${component}_FOUND)
    SET(XXX_FOUND FALSE)
  ENDIF (NOT XXX_${component}_FOUND)
ENDFOREACH (component)

# handle standard args
FIND_PACKAGE_HANDLE_STANDARD_ARGS(XXX DEFAULT_MSG XXX_FOUND)

- Create a list of clean, standard compliant, non-patched cmake
modules that can be used as example references for module developers.
This could be added in the Module maintainer wiki page and/or the
readme.txt and would add context to the specs in the readme.txt file.

--Miguel