Imprecise cropping of semi-large images (e.g. 1280x1024 becomes 1281x1024)

[Jack_956]

I often use IrfanView to make full-screen centered wallpapers for my 1280x1024 resolution monitor.

Often, when I've got an image ready for the final crop, I'll draw a 1280x1024 selection but it ends up as 1281x1024 after I click Edit + Crop Selection. The pixel size error tends to be in the horizontal dimension, but that's probably because I usually resample to the vertical dimension first, then crop the edges (usually dragging from the left). The bug isn't restricted to any particular image size, but that's a typical example in my experience.

It also happens (but less often) when I use the Custom Crop Selection feature. I tend to do such cropping when the image is zoomed out to a fair degree, since cropping at actual size is sometimes impossible.

It seems to happen much less often with smaller images, e.g. 640x480, where I can easily crop while viewing at full resolution.

[Bhikkhu Pesala]

Are you using the latest version?

Cropping at actual size is never impossible, just set the custom selection, move the cropped area with the right mouse, and press Ctrl Y to crop to the selection. I think that should avoid the rounding errors that might happen if zooming out.

Even if the image is very large, you can zoom out, make the custom selection, zoom to original, then crop.

[Jack_956]

Are you using the latest version?

Cropping at actual size is never impossible, just set the custom selection, move the cropped area with the right mouse, and press Ctrl Y to crop to the selection. I think that should avoid the rounding errors that might happen if zooming out.

Even if the image is very large, you can zoom out, make the custom selection, zoom to original, then crop.

I've had this error up to v4.25. Just downloaded v4.27 and can't replicate it at the moment, but I doubt that will fix it. Maybe 1 in 8 times the horizontal dimension will be off. It seems to depend on where you start dragging the crop box on the image but it's hard to say. It's a random sort of thing.

Cropping at full resolution (on images much larger than screen-size) takes a lot more work and you can't get the full overview for aesthetic cropping. I don't think it should be necessary if the pixel readout can be trusted. I've never had this problem with another freeware app, XnView, which I mainly use when IrfanView won't crop accurately.

[Bhikkhu Pesala]

It seems that the bug has been fixed in 4.27 — if you are still able to reproduce it, let us know, and the thread can be moved back again to bug reports.