Re: Comparing NSImages
Re: Comparing NSImages
- Subject: Re: Comparing NSImages
- From: Benjamin Rister <email@hidden>
- Date: Fri, 24 Jul 2009 12:11:32 -0400
On Jul 23, 2009, at 5:19 PM, Nick Zitzmann wrote:
Considering that there are several different variations on the TIFF
file format (e.g. big-endian vs. little-endian, 0 is black vs. 1 is
black, and then there's metadata), this would not surprise me.
Yeah, that's what I expected, thanks.
On Jul 23, 2009, at 5:39 PM, Greg Guerin wrote:
Subtract the test's output image from the reference image, pixel by
pixel, and look for any non-zero differences. This assumes
compatible representations and no differences introduced by any
other image-handling steps (e.g. device-RGB is device-dependent, so
can't be assumed to be unvarying).
Even so, you might encounter small non-zero differences that
originate from outside your code-under-test. If these are larger
than +/-1 they could be significant; +/-1 I'd probably accept as
within the margin-of-error for rounding.
Thanks, I didn't know if there was a cleaner way than doing it pixel-
by-pixel myself; the info on reasonable tolerances is also quite
helpful.
I've tracked down the problem using this method (unfortunately, can't
yet write about the issue here for the archives); thanks to everybody
for their help.
Benjamin Rister
_______________________________________________
Cocoa-dev mailing list (email@hidden)
Please do not post admin requests or moderator comments to the list.
Contact the moderators at cocoa-dev-admins(at)lists.apple.com
Help/Unsubscribe/Update your Subscription:
This email sent to email@hidden