Fixed Use Resample for Zooming Freezes PC

[Bhikkhu Pesala]

1. Open a medium or large image. I was able to reproduce this bug with an image of only 1300 x 982 Pixels (1.28 MPixels).
2. Enable View, Display Options, Use "Resample" for zooming.
3. Select a small area (about 75 x 75 pixels).
4. Click inside it to zoom in

Result If the area is very small, relative to the image, resample won't be used, so zooming is instantaneous. However, if the zoom level is high, but just low enough for resampling to be used, IrfanView will freeze. I presume that it will also depend on how much memory you have installed.

I was unable to terminate IrfanView and had to use the power button.
On restarting my PC I had to run checkdsk, which took about ten or fifteen minutes, so if you test this bug be warned that it could cause such problems.

The freezing is very easy to reproduce, but if the zoom level is not too great, IrfanView will eventually recover and the selected area will be zoomed to.

At a certain critical point, IrfanView looks like it is never going to recover — if you are prepared to wait long enough, perhaps it will recover every time. I was uncomfortable with letting my hard disk thrash for longer than two or three minutes.

[Bhikkhu Pesala]

Resample for zooming is still unusable with the so-called fixed version.

1. Opened large JPG image 3906 x 2602 Pixels
2. Selected an area and zoomed in to about 600%
3. Enabled Use resample for zooming in View, Display Options
4. Zoomed out using the keyboard

Program froze with lots of disk thrashing after about twenty seconds, so I terminated the program (with considerable difficulty).

[Skippybox]

The fixed version does not solve this problem, it simply makes the two resample settings truly independent.

I would be afraid to ever use IrfanView's resample for such a zoomed image. You're talking about making a 366MP image on screen; that's easily taxing for a system. As always, I would use resampled zooming selectively.

[Bhikkhu Pesala]

Version 4.23 seems to be doing a better job than 4.25. It doesn't use resampling above 500% zoom at all, and below that, although it freezes, it does recover after a while. Edit: I spoke too soon, it did just lock up my PC completely. Conclusion: resample while zooming is best avoided.

I think IrfanView could do a lot better simply by resampling only the viewing area instead of the entire image. Even on a high resolution monitor 1600 x 1200 pixels is not too much to cope with.

[Skippybox]

Version 4.23 seems to be doing a better job than 4.25. It doesn't use resampling above 500% zoom at all, and below that, although it freezes, it does recover after a while. Edit: I spoke too soon, it did just lock up my PC completely. Conclusion: resample while zooming is best avoided.

This is what I've been saying. 4.25 should not behave all that differently than 4.23. Resample while zooming is not really a new feature, just a new menu item and a dedicated function. It's possible Irfan has tweaked it someplaces, I don't know, but it's still the same little devil it's always been.

I think IrfanView could do a lot better simply by resampling only the viewing area instead of the entire image. Even on a high resolution monitor 1600 x 1200 pixels is not too much to cope with.

I agree, if Irfan did nothing else to move to a better technology for resampling, this should at least be done. I mean, why do the whole image, if it is questionable whether a user will even pan/scroll?

[Kailuz]

Approximately same question I have.
After showing “Effects browser (^E)” zoomed picture is resampled even when “Resample for zooming (windows mode)” is OFF (no resampling only if “Resampling for fitting” is turned OFF too). And for big pictures is to long for wait resampling finished. Is it normal or not?

[Skippybox]

I think this is normal, because that is the way it worked in the last version, 4.23. When you leave Effects, for some reason the image wants to refresh and so it will be resampled. The difference in 4.25, is that all display options behave the same, so the effect is more widely seen. I would turn off resample for fitting if you do not want that to happen. I agree, I don't see a reason for the refresh, but it happens throughout the program for other actions too.

[rkrz]

Zoom sloooowwww in 4.25 from 4.10

Upgraded from 4.10 to 4.25, windows xp, R51. Using same .ini file as 4.10, with no resampling on zoom, found zoom of selected area so slow that thought program was frozen. Just didn't wait long enough. Uninstalled and went back to 4.10, now all fine again, with instantaneous zooming of any selection. These are all JPG files.

Any ideas what has happened?

[Skippybox]

Simply turn off Use "Resample" for zooming in View->Display options (window mode).