0.56 - W8/x64: Batch convert - crop preview is wrong

[StephanP]

I created a series of screenshots (full screen, Winkey-PrtScn) that obviously needed te be cropped afterwards.
The following problem occurs in XnViewMP 0.56 (on W8/x64).
I select the images
I start the function "Batch Convert"
I select the action "Crop"
Initially the crop preview on the right shows the full picture in its right size
After I have applied some top, left, right, or bottom crop values, the crop preview does NOT exactly match the result of the values I just entered.
The crop preview makes you think that more is cropped than would correspond to the values entered.
In short: If you enter crop values by using the crop preview, you will end up with images that are still too large.

If on the other hand you opened the image in another application and determined the applicable crop values there (with a bit of calculation), then applying these values in XnViewMP - Batch convert - crop will work perfectly. So the cropping in itself is fine, it's the crop preview that appears to be off.
Stephan

[xnview]

Strange, the crop applied is the same on preview and final picture

[StephanP]

I was - of course - experimenting a bit with the crop values
I set some values, I clicked the update button bar in the middle and used the zoom function on the right to check if the desired effect was obtained.
In this process, the crop preview wanders off, displaying more cropping than will be effected in the end.
I'll try and see if I can make a demo video or animation of this.

[StephanP]

I did another experiment and there's definitely something off.
Take for instance attached screenshot.
If you open the file in yet another paint app, then you can determine that cropping the XnViewMP window will require the following crop values:
Top: 56
Bottom: 129
Left: 112
Right: 107

Now, without the above knowledge, use the crop preview and try to set the crop values, cutting out the XnViewMP window in the middle of the screen shot.
In this process, there'll be some increasing/decreasing of values on the left, clicking the "apply action" in the middle and zooming in/out and panning on the right.
At some point you may notice something strange happening to the picture, but then again you may miss it altogether as well.
Anyway, when you think all valueas are correctly set, then you may find that these do not correspond to the above mentioned values.
And if you actually perform the action, the resulting image will have an offset and the crop is not made as intended.

[xnview]

If i enter these values or use slider, the result is good in preview and output