Double page mode has no effect on some pages

[beaverdude]

Two volumes of the same comic book in CBR. Similar jpg naming inside, same page sizes.
One is being displayed in double-page mode, while the other one does not react on that mode, single page only I see.
I can't spot any difference in CBRs, any idea why the double-page mode can be ignored for one file?

SYSTEM INFORMATION
Qt version: 6.3.1
Build ABI: x86_64-little_endian-llp64
build CPU architecture: x86_64
CPU architecture: x86_64
Kernel type: winnt
Kernel version: 10.0.22635
Product info: Windows 11 Version 2009

GRAPHIC INFORMATION
Screen pixel ratio: 2.5
OpenGL version: 4.6 desktop

[beaverdude]

v3.zip
example attached. Cover + 2 pages from a good volume + 2 pages from a problematic volume.
2-3 pages stick together in double-page mode, while 4-5 are displayed as singles.
Moreover 'go to flow' doubleclick to jump to a page works only if 2 or 3 pages clicked. Doesn't work for 4 and 5.
all pages are identical except datetime and size (matter of several pixels)

v3/TSoL-AJT-01-03.jpg: JPEG image data, JFIF standard 1.02, resolution (DPI), density 72x72, segment length 16, Exif Standard: [TIFF image data, big-endian, direntries=7, orientation=upper-left, xresolution=98, yresolution=106, resolutionunit=2, software=Adobe Photoshop CS3 Windows, datetime=2011:04:02 02:04:11], baseline, precision 8, 1680x1693, components 3

v3/TSoL-AJT-01-04.jpg: JPEG image data, JFIF standard 1.02, resolution (DPI), density 72x72, segment length 16, Exif Standard: [TIFF image data, big-endian, direntries=7, orientation=upper-left, xresolution=98, yresolution=106, resolutionunit=2, software=Adobe Photoshop CS3 Windows, datetime=2012:02:01 01:02:12], baseline, precision 8, 1680x1680, components 3

[beaverdude]

Hm, by some reason the app didn't like square pictures? I changed 4 and 5 pages aspect a little bit with gimp from 1680x1680 to about 1680x1700 and they assembled into a double-page mode view. Bug?

[beaverdude]

Well, after some experiments to image sizes, even 1px width-height difference matters.

Double-page view works perfect when image WIDTH < HEIGHT regardless of actual pixel numbers.
In case WIDTH >= HEIGHT it is displayed as a single page only.

I afraid buffer[currentPageBufferedIndex]->height() > buffer[currentPageBufferedIndex]->width() here is too strict.
May I suggest ">=" ?

https://github.com/YACReader/yacreader/blob/be90e9e3a12a31595914535c0457eda2e04ef1bb/YACReader/render.cpp#L549C6-L549C39

[luisangelsm]

The double page mode tries to detect single page spreads to avoid showing a single page next to a double page spread. Those images are always shown as a single image. Those squared images are being detected as spreads...

[beaverdude]

as a workaround I just chopped 1px from each square image in bulk.