Performance issue

[EHadoux]

Hi, are pure ruby or no dependencies constraints somewhat mandatory? I already have in my code rmagick so I rewrote (almost) yours and the gap of performance is huge. Maybe being able to choose would be a good thing?

Cheers

[ansoni]

Not a requirement, but having a no-dependency option is nice. I'm all for a code snippet(code is so simple) or a pull request:-)