Page 1 of 1

1.9.3: Off-center rendering on startup

Posted: Thu Aug 21, 2025 4:00 pm
by tyb
XnView: MP 1.9.3 - 64 bit
OS: Windows 10 64bit

When in "Fit images to Desktop" zoom mode and startup in Viewer mode, there are scenarios where the image will be initially rendered off-center in the window, then after about one second, it will shift into the correct place within the window.

This can be reliably reproduced in a couple of ways:

Method 1:
Load an image - double click to enter browser mode - exit application. Open the same image again. It will render off-center then snap into place a second later.

Method 2:
Find two images with very different aspect ratios, e.g. one in portrait and one in landscape. Open one of the images. Close the application. Open the other image.

I'm guessing the problem is there is some caching of viewport dimensions and/or coordinates going on behind the scenes. The previous render is influencing how the next render begins. Then when it finds the initial render is off-center, it re-renders the image correctly. The visible shifting is rather jarring and should be avoided or be fast enough to not be noticeable. I'm also guessing the same process happens when you navigate from one image to the next in viewer mode, just that the re-adjustment is so fast that it's almost imperceptible.

It may or may not be important, but I also have the catalogue completely disabled.

Re: 1.9.3: Off-center rendering on startup

Posted: Thu Aug 28, 2025 11:59 pm
by tyb
So I happened to read another bug report about XnView operating slowly when processing an image in a directory with many hundreds to thousands of images. That sounded like me so I tested it and the directory size contributes to the behavior I reported. Using the same images and the steps mentioned in the report, I did not see the slow and visibly off-center rendering when viewing from a small directory. When I moved the images to the large directory, I then saw the slow off-center rendering.

That said, even when rendering from a small directory, I still see the window dimensions shift around. It just happens so fast that its almost imperceptible. The issue of using the wrong dimensions to initiate rendering seems to also contribute to the issue.

Re: 1.9.3: Off-center rendering on startup

Posted: Fri Aug 29, 2025 5:50 am
by user0