From: Tim Hunter <cyclists@...>
Date: 2004-05-20T20:43:48+09:00
Subject: Re: RMagick jp2 problem

On Wed, 19 May 2004 20:15:24 -0600, Ara.T.Howard wrote:


> what is the most __effecient__ (we are dealing with HUGE images) to
> compare the raw pixel values of two images using RMagick, eg (not
> efficient psuedo code).
>

Assuming you want to compare entire images and get a single result, you
can use the channel_compare method to compare individual channels or all
the channels at once.

Or possibly use the composite method with the DifferenceCompositeOp to
produce a difference image.

Any approach where you use Ruby to inspect individual pixels is
going to involve a lot of overhead, since RMagick has to convert each
pixel to a Pixel object. (And Pixel objects are heavier-weight than you'd
imagine.)