Display image dimensions and aspect ratio in status bar

[j03l]

Add a new status bar widget showing image dimensions and simplified aspect ratio (e.g. "800 × 600 · 4:3"). The label updates on resize, rotate, undo/redo, and document switching.

The selection size widget previously showed the canvas dimensions (e.g., "800, 600") even when no selection was active. This was because ResetSelectionPaths() in Document.cs creates an invisible selection rectangle covering the full canvas, and the status bar handler read its bounds without checking Selection.Visible.

Before my changes, this was arguably useful, it was the only place showing the canvas dimensions. But now that I've added a dedicated image dimensions widget ("800 × 600 · 4:3"), showing the same numbers in the selection widget is redundant and misleading. It looks like there's an active selection when there isn't one. So I hide the selection widget entirely until the user actually makes a selection.

Ref: #1994

[cameronwhite]

Thanks for working on this!

I'll look through the code more closely later but gave it a quick try
Trying it out on macOS I had some layout issues (attached video)

• There is a lot of extra space to the right
• After making a selection the palette ends up being cut off. This probably depends on the window size and how much space is available

statusbar.mp4

[j03l]

Thanks for working on this!

I'll look through the code more closely later but gave it a quick try Trying it out on macOS I had some layout issues (attached video)

• There is a lot of extra space to the right
• After making a selection the palette ends up being cut off. This probably depends on the window size and how much space is available

statusbar.mp4

Interesting! The palette being cut off is actually in the live version of Pinta. I'll have a play around.