#64 ✓fixed
Virgil Dupras

dgpe misses dupes when transparency is involved

Reported by Virgil Dupras | September 28th, 2009 @ 05:23 PM | in se2.8.1 me5.6.5 pe1.7.6 (closed)

After having noticed that some exact duplicates had a less-than-100% match in the Cocoa version, I investigated for a few hours (yeah, it took me quite a while to click on that one) and found that images with transparency were the problem.

After some digging I found out the cause of the problem, which is the malloc() on the BitmapContext creation routine. This pixel buffer initialization doesn't zero out the pixels, and when the image is drawn in the buffer, transparent pixels are not touched, which means that these pixels stay undefined.

It means that two pictures that are exactly the same will most likely have different block when analyzed (which is bad).

Comments and changes to this ticket

Please Sign in or create a free account to add a new ticket.

With your very own profile, you can contribute to projects, track your activity, watch tickets, receive and update tickets through your email and much more.

New-ticket Create new ticket

Create your profile

Help contribute to this project by taking a few moments to create your personal profile. Create your profile ยป

Shared Ticket Bins

People watching this ticket


Referenced by