how to rotate in a selected area

[lilarcor]

Hello,I want to edit an area in a big size picture.How I can do it? Does irfanview has this function? Help.

[Bhikkhu Pesala]

You can edit within a selected area using the IrfanPaint plugin (F12), but rotation can only be applied to the whole image.

Image Effects (Ctrl E) like swirl can be applied to a selected area. Just select the area you want to manipulate and open the Image Effects dialogue.

[Mij]

Hello,I want to edit an area in a big size picture.How I can do it?

It is often useful to open a second copy of Irfanview (after first unchecking "Only 1 instance of IrfanView is active" in Properties>Misc1 ).
Drag a selection box around the area you want to edit and Copy it to the clipboard (Edit>Copy or Ctrl+C). Minimize if necessary and open the second copy of Irfanview. Paste (Edit>Paste or Ctrl+V) and edit the image how you want it. Then Copy that to the clipboard, return to your first Irfanview and Paste it back into the selection in your big image.
In v4.20 there are now two different options for pasting, "Fit to selection" or "Stretch to selection", set in Properties>Misc3. If you want to rotate the image in the second Irfanview, then you will clearly need a square selection or use the second option and accept the distortion of the aspect ratio.

[Skippybox]

Edit>Create custom crop selection might help you during the cut/copy process.

[matera]

If you just want to rotate 90 degrees or flip vertical or horizontal, using two IrfanView windows will work perfectly. You can paste back into the original selection if you don't disturb it.

The fine rotation would not be practical, since IrfanView can not paste transparently. A workaround might be to rotate the whole image, after adding canvas to avoid losing the corners, and then paste back the selection (with custom selection as mentioned above) and rotate it back again, with huge loss of quality. It would be interesting (meaning fun lol) to experiment with it.

[Mij]

The fine rotation would not be practical....... It would be interesting (meaning fun lol) to experiment with it.

I had not considered a fine rotation, Matera, but what I would do is to copy an oversized area to Irfanview 2 and rotate that. Then make a smaller selection in 2 (well inside the blank canvas edges) and copy that back. That is where Skippybox's contribution comes in. After making the copy in 2 you can open Custom selection box (Shift+C), press Save Current values and close the box.
Then back in Irfanview 1 open Custom selection again and Apply to Image. Lo and behold, the same size box as you copied. Right click and drag it to where you want, then paste.
Obviously it would only be appropriate in certain situations but I think perhaps you could make the Leaning tower of Pisa stand up straight against a clear blue sky. Might need a bit of touching up with IrfanPaint, but fun as you say.

[Mike_BossO]

Easiest way for me was.
- open an image
- make a selection and copy it (CTRL+C)
- open new empty IrfanView window (e.i. through Windows Start menu)
- paste a selection (CTRL+V)
- rotate image (hotkeys: L, R, V, H, CTRL+U)
- select whole image (CTRL+A) and copy it (CTRL+C)
- switch back to previous image, make sure if previous selection is set and just paste rotated image from clipboard (CTRL+V)