How do I mirror something exact if it's not 100% equal in rotation?

[DeltaLCR]

I accidentally rotated a P-51C i was editing for a project a bit too far, causing it to be asymmetrical. I want to copy a stripe from one side to the other but I don't know how to no matter how much I have tried.

[Pixey]

Hello @DeltaLCR and Welcome to the forum   

 

You could make a new layer above the image.

With the Rectangle select, use the Move Selection Move selection tool.

Hover over the yellow stripe until it matches the size/position.

Use the Paint Bucket to add the yellow color.

Use feather, or AA's Assistant to clean the edges.

Flip horizontal and align.

[DeltaLCR]

2 minutes ago, Pixey said:

Hello @DeltaLCR and Welcome to the forum   

 

You could make a new layer above the image.

With the Rectangle select, use the Move Selection Move selection tool.

Hover over the yellow stripe until it matches the size/position.

Use the Paint Bucket to add the yellow color.

Use feather, or AA's Assistant to clean the edges.

Flip horizontal and align.

Thank you!

[Pixey]

I found that you will have to move the yellow strip after you flip horizontally, to match up the placement:

 

[MJW]

12 hours ago, DeltaLCR said:

I accidentally rotated a P-51C i was editing for a project a bit too far, causing it to be asymmetrical.

 

I recommend you purposely rotate the P-51C so that it's symmetrical. You can use BoltBait's Level Horizon/Plumb Bob plugin. Afterward, you should also center it with the xod's Align plugin. 

 

 I suggest the following steps:

 

• Sample the background color with the Color Picker tool, making it the Primary Color.
• Duplicate the image layer.
• On the top layer, use the Lasso tool to select the plane and nothing else but some of the background. The selection does not need to be in the least bit exact. Just make sure to surround the plane, and include nothing else except background. in other words, exclude the text and the border.
• Fill the selection with the Primary Color to eliminate the plane. This will be the new background for the image.
• Move the lower layer to the top, and make sure it's selected.
• Invert the selection.
• Fill the inverted selection with the Primary Color to eliminate all but the plane.
• Clear the selection (i.e., Deselect).
• Use the Magic Wand with a fairly low tolerance to select the background of the top layer without selecting any of the plane. The tolerence should be low enough that none of the pixels on the plane's edge are selected -- only pure background.
• Erase the selection (so only the plane remains).
• Use the Level Horizon/Plumb Bob plugin to straighten out the plane. You can either do it horizontally by using the lines on the wing, or vertically by using the plane's mid-line.
• Run the Align plugin to center the plane. (You may only want to center it horizontally.)

 

Now do whatever you want to the plane. Believe me, one thing experience has taught me is that it's always easier to make things well-positioned in the first place, rather than to always be working around bad positioning.

 

Once you're done, you can reposition the plane if you want, then flatten the image.

 

If the image you show is the actual scaling, you might want to double the size of the image before working on it, then resize when you're done. It would make things easier.