Adds ViewportSettings.Transparent

[tig]

Fixes

For

• Popover - A consistent way of enabling a Subview to popup outside of a View #3691

We need the concept of a view that is transparent. In addition I've found that View.Draw has some errors in it regarding in how clipping is done.

This PR fixes those issues and adds the new capability.

• Adds ViewportSettings.Transparent enabling see-through/click-through views
• Adds ViewportSettingsEditor to Scenarios and expands AllViewsTester to utilize

Proposed Changes/Todos

• Add ViewportSettings.Transparent
• Add ViewportSettingsEditor to Scenarios and expand AllViewsTester to utilize
• Upgrade ViewportSettings scenario to use ViewportSettingsEditor and illustrate transparency
• Add ViewportSettings.Transparent unit tests

Pull Request checklist:

• I've named my PR in the form of "Fixes #issue. Terse description."
• My code follows the style guidelines of Terminal.Gui - if you use Visual Studio, hit CTRL-K-D to automatically reformat your files before committing.
• My code follows the Terminal.Gui library design guidelines
• I ran dotnet test before commit
• I have made corresponding changes to the API documentation (using /// style comments)
• My changes generate no new warnings
• I have checked my code and corrected any poor grammar or misspellings
• I conducted basic QA to assure all features are working

[tig]

Note, it's unlikely that this will support a transparent view with subviews that use transparent shadows.

[tig]

[tig]

Pretty excited about this.

I had to do a ton of work in View.Draw and Region to get this to work. And build a bunch more unit tests.

In doing all this I remembered SkiaSharp and have a stash where I ported Region to use SkiaSharp under the covers. I plan on doing some benchmarking to see which is faster.

[tznind]

Oh, nice! That looks awesome 🔍

Is it a draw effect only, or do clicks also drop through input transparent areas?

Could be nice future addition to optionally have that behaviour.

[tig]

They don't yet. But will.

The point of this is to enable Popovers.

[tig]

@tznind this is with v2win... Really great sign! Nice work!

[tznind]

this is with v2win

Nice! 💪

Region Scenario [...] we should combine this with the LineDrawing Scenario?

Yeah probably one drawing scenario with all the tools side by side would be nice, but it doesn't have to happen right away if its difficult.

[tig]

You'll note the draw path has been simplified/cleaned up in addition to the transparent support being added.

Also, Region is much more robust.

[BDisp]

Some questions:

• Is correct to be the same arrow in all edge corners?
• Why resize acts differently when press on the boundary and when press on the top border?

[BDisp]

Lovely work. Only 2 suggestions.

[tig]

Some questions:

• Is correct to be the same arrow in all edge corners?

No. Bug. Not related to this PR.

• Why resize acts differently when press on the boundary and when press on the top border?

Not related to this PR. Not exactly sure what you mean. But probably a bug.

[tig]

I updated the Text Alignment & Direction Scenario to make the Views be transparent to illustrate how TextFormatter.GetDrawRegion works.