BDReader is a simple open-source comic reader with support for PDF, CBR and CBZ files, and image (RAR, ZIP, TAR CB7 and 7Z files).
The core of the program is very simple. Click File > Open, choose a file; zoom in and out, click left/ right to move backwards and forwards, up/ down to jump a page at a time, Home/ End to move to the start or end of a file, and that's it.
What you do get here is a Panel mode, which uses computer vision technology to detect the panels in a page, and display them in reading order. at the maximum possible size for your page. This gave inconsistent results for us, but it did sometimes work very well, and when it failed there seemed to be no down side: BDReader just displayed the entire page full-screen and allowed us to view or scroll it as normal.
If you're not so lucky with Panel Mode then you can turn it off, and switch to a full page or page width view.
There's also an optional sidebar which displays a thumbnail of the entire page, regardless of your main viewing settings.
Version 1.04 (Release Notes):
-Border transparency when In Context
-Pages rotation option (+90,-90,180)
-Several bugs fixed (InContext switching, 'random' crashing, fallback to STRIP mode, global zoom preferences...)
-Icon displayed in Windows version
-PDF files now loaded at 300dpi