Bug: Proportional Resizing of Selection

[Sword of Apollo]

Thank you very much to all of the developers and plugin creators of Paint.net. I find it to be a very useful and intuitive app.

 

I'd like to report that, in 4.0.17, resizing a selection doesn't behave as one would expect under certain circumstances. When you select something, then modify the dimensions of that selection arbitrarily, then attempt to resize it proportionally by holding Shift, the proportion of the selection reverts to what it was before the modification.

 

This is strange behavior that older versions of Paint.net didn't suffer from.

 

Thanks.

[MJW]

That does seem strange. I was going to tell you to press Finish before beginning the second resize, but discovered that even after pressing Finish, the selection reverts to the initial proportion when Shift is held down.

[MadJik]

@Sword of Apollo 

Hi and welcome to the forum.

 

This behave isn't new to me.

Ctrl+i twice do the trick (invert the selection two times).

 

When I need such complex selections with resizing adding subtracting, I use a new layer to fill the selection with a color. And do all change on that layer. Just use the magic wand tool at the end to have my selection I need.

 

 

[Rick Brewster]

This is exactly how older versions of Paint.NET have always behaved, and it is not a bug.

 

The aspect ratio that is used for constraining is the original aspect ratio. The reason for this is that things get much worse and weirder if the current aspect ratio is used. Selections are generally confined to integer (whole number) sizes, and almost every constrained resize will introduce some rounding error. For example, taking a 10x9 selection and making it 10% larger will result in an 11x9.9 selection. But because of integer rounding this will be 11x10. Now the aspect ratio is 1.1 instead of 1.1111111. If the current aspect ratio is then used, it will distort the next attempt at a constrained resize.

 

Like MadJik suggests, if you want the current aspect ratio to be used then you need to manually do something that causes that information to be reset. Inverting the selection twice is a very good choice for this. Another example would be to use the Rectangle Select tool and to either subtract a part of the selection that isn't selected (a no-op), or to add a part of the selection that is already selected (another no-op).

[Sword of Apollo]

Alright, thank you, Rick and MadJik. That's an easy-enough workaround for when I need it.

 

It's odd, because I used v3.36 and v3.5 quite a lot some years back, and I don't recall ever noticing that behavior. Maybe I just never had occasion to do an unconstrained resize, followed by a constrained resize.

Edit: Perhaps this would be too complicated or work-intensive to do, but just a thought: Would it be possible for an unconstrained resize to generate a new "original" aspect ratio, but a constrained resize not to do so?

Edited September 3, 2017 by Sword of Apollo