Mirror an image diagonally?

[tomy]

Seems like it should be simple right? Mirror the image horizantally, then vertically. Then take the top right triangle and paste it over the new image. Unfortunately, that result in something different that expected. Take the following image (sorry for 5 second image and a lack of drawing skills):

 

 

and here is what you get instead:

 

 

Rotating the image 180 degrees gives same result. But I know this is possible, it has to be! I can draw a picture both in my mind and in theory of what it would look like. It can be done on paper, just paint one side and fold it over the other. And in theory you could rotate the image 45 degrees, slice it and mirror it that way, but then pixel accuracy is lost, not to mention is works only with perfect squares. So how is it done? Any plugin for this, or can it even be done without? What method am I missing? Is it possible at all with rectangles? I did try a plugin called Mirror / Flip, but it didn't seem to do anything I couldn't using Paint.NET's normal menu.

 

Thanks for any help

[Rick Brewster]

A CodeLab script could probably do this pretty easily ... *hoping for someone to post one here for me... *

[Ego Eram Reputo]

Mirror over Line

 

Results may be odd as you have an image with unequal W & H, but here's what I got

 

 

You may need to select and stretch the results to fill the lower left corner.

[tomy]

Hmmm... I wonder how I could go about doing that... perspective maybe.

Anyways, thank you so much for the recommendation!

Edited July 19, 2014 by tomy

[yellowman]

Hi tomy, I am not sure if I correctly understood what are you trying to achieve,

But if you are after this result, then let me know, it is pretty easy (but hard to figure out) without using any plugin or effect.

 

Edit: sorry grammar mistakes.

Edited July 20, 2014 by yellowman