[Melbourne-pm] Image Manipulation

Rick Measham rick at measham.id.au
Fri Apr 28 14:41:20 PDT 2006

Scott Penrose wrote:
> 3) Write an external wrapper - yet another abstraction, just for the 
> most basic of functions - height, width, resize, rotate... Really the 
> same as 2 but make it more usable outside. A little harder to write, new 
> tests, module space etc.
> My current thoughts is leaning in on 2.
> 3 worries me a little for two reasons: It is an unnecessary abstraction 
> - using the Simple driver of Gallery you can already achieve what you 
> would otherwise with 3, so just use Gallery (this is a sort of); where 
> would it go, it seems that people writing modules such as 
> "Image::Resize" have this sort of in mind, but have limited to one 
> function, and one backend.

G'day Scott,

I started working on (3) a couple of years ago and stopped when my 
interest waned. If you want to go that way, then I'm happy to pick it up 
again and release it.

I think I called it Graphics::Abstract.. it had no requirements of its 
own, however you could then install Graphics::Abstract::ImageMagick or 
Graphics::Abstract::GD (or ...) which would each have a dependency on 
their given CPAN Module.

Internally we check if the ImageMagick plugin is installed as it's the 
most feature-filled plugin, then degrade slowly. (Latter thoughts 
include writing to Graphics::Abstract::Config in the make process each 
time a plugin is installed, which would mean we don't have to keep 
trying to load stuff :) )

Of course, each of these plugins has fewer features than others and so 
you'd need to be checking for error messages. This makes manipulation 
chaining difficult, though it will be possible:
    print $gfx->errmsg();
    # The GD library does not support flip(). Please consider installing 

Anyway, if you're interested, I'll pick it back up again :)

Rick Measham

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