FR: IDE-style marks on scrollbar

[mcpiroman]

Summary of the new feature/enhancement

Introduce marks and indicators on scrollbar:

1. Command seperators / prompt positions

• Program runs and you want to see how long the current output is. You can look at scrollbar and see where is the last command marker.
• You run gcc --help=common that prints ~900 lines of output, and you know the interesting switch is somewhere in the middle. By viewing the command's input line position you can easily navigate to that location.
• You are running well-known batch script and want to know current state. You can look at scrollbar to count number of commands that has already run or even notice that second command has abnormally big output.
• Just helps with navigation over previous command.

2. Selection span

• Not as usefull but nice looking.

3. Colors of text / lines

• You run some build script that prints errors in red and warnings in yellow. You can leave it running and them just glance at scrollbar to see if there are any issues (and locate them).
• You run some port scanning script (like this) that prints successful connections in green and unsuccessful in red. Much like above.
• You run git status that prints everything in green, but then look at scrollbar and see that one, sneeky, unstaged, red line.

Example looks:

Visual Studio	IDEA InteliJ

Proposed technical implementation details (optional)

• This should be controlled by per profile settings
• When there is one line, say red, surrounded by great number of green lines, that red dot or strip should have some minimum size to ensure it's visible.
• When only part of the line is colored it should be show the same way as if whole line was colored
• What if there are two colors on same line?

[DHowett-MSFT]

Clever feature request, and one we haven't seen before. Thanks!

[mcpiroman]

Technical consideration: Should the scroll bar be implemented as:

1. ScrollBar as it is now, but with some custom overlay drawings (idk if that's possible)
2. New control based on uwp primitives (just like the ScrollBar is implemented)
3. New control based on custom rendering, potentially SwapChainPanel

[DHowett-MSFT]

We've had a "minimap" on our backlog for a while, so this would be a logical extension/step to that. I'm marking this one as backlog. 😄

[zadjii-msft]

I'm no XAML expert, but I'd think it'd be possible to put some sort of transparent control over the bounds of the scrollbar, and draw rectangles into that area. We'd have to be careful not to accept any mouse input in that region, but that seems possible to me.

Now here's a question - if we're not doing this "minimap" style, and instead we're just putting little ticks there, how do we determine a tick should be placed? The terminal doesn't know when one command starts or ends, so the shell would have to communicate that to us somehow. Alternatively, we could try a keybinding that the user presses to manually add a tick - though that might not be the best either. Additionally, how would a tick get removed? Could the user click on them to change colors/delete? If so, I'd probably prefer the VS style ticks.

(I'm adding the extensibility tag, since this seems like a good extension case)