From graphics-request at octave dot org Tue Feb 21 22:14:11 2006
Subject: imshow.m
From: Daniel J Sebald <daniel dot sebald at ieee dot org>
To: octave graphics <graphics at octave dot org>
Date: Tue, 21 Feb 2006 22:20:54 -0600

I see that imshow.m has had a major rewrite and looks to be a big improvement.  Petr and I wondered about the behaviour, i.e., why the image seemed so dark so often.

Well, I see there was a division by 255 in the old code, which to me was just not right.  Now imshow() appears to maintain intensity for matrices with values between zero and one.  Then anything beyond that appears to be scaled.  I might simply prefer saturating the image, or a little warning on the screen that the image is being scaled would be fine too.  It's just that "sometimes scaling/sometimes not" always leaves some linguring doubt if a colleague asks, "Was this scaled?".  "imagesc" is meant to scale.  Maybe image routines without "sc" should not be scaled.  (Not a strong opinion.)

Are the "zoom" parameters in the image routines necessary anymore?

Dan