Premultiplied display mode

Ideas for improvements and requests for new features in XnView MP

Moderators: XnTriq, helmut, xnview

Lex-DRL
Posts: 5
Joined: Mon Sep 02, 2024 1:07 pm

Premultiplied display mode

Post by Lex-DRL »

Some files (EXR specifically) often contain color in a premultiplied format. It would be nice if XnView had an option to display them as such. Currently, a fully-additive premultiplied EXR (e.g., containing only an additive fire in color but a fully transparent alpha channel) is displayed as fully transparent.

I'm attaching an example image. It contains a fire with very transparent alpha, but a lot of glow in RGB. It should be drawn as very bright mostly-additive (but partially opaque, too). Instead, it's displayed by XnView as barely visible and very dark (a well-documented effect of double pre-multiplication).

How it should be displayed:
_right.jpg
The current XnView behavior:
_wrong.jpg
_Fire.7z
Preferably, there should be:
  • a per-file-type premultiplied/un-premultiplied display-mode association, with most (or all) of the files being associated to "un-premultiplied" mode by default (and only EXR and, maybe, TIFF being set to premultiplied);
  • a hotkey to switch this mode on the fly.
P.S.: sorry if an option is already there. I tried to find it, but failed.
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