uilist line padding accounts for number of lines in text

[RenechCDDA]

Summary

Bugfixes "uilist line padding accounts for number of lines in text"

Purpose of change

• Fixes incorrect vertical size of uilist menus #75698

Describe the solution

Padding is applied between each line ( s.ItemSpacing.y * expected_num_lines ) and then also two at the top and bottom of the text: ( s.ItemSpacing.y * 2.0 ). Previously the calculated padding area only account for the top and bottom, meaning that each additional line of text ate up more and more vertical space that the window wasn't expecting

I'm not sure why ImGui::CalcTextSize() isn't already returning this properly

Describe alternatives you've considered

There is probably somewhere more fundamental to apply this, like the static calc_size

title_size and desc_size are both calculated the previous way, and technically those likely do have the same error unless changes are made to them/calc_size

I am sure there is a better way to do this, I just don't know what it is!

Testing

See my beautiful images at the comment I made in the linked issue

Additional context

[RenechCDDA]

I guess we can just mark this ready and see if any objections come up. It shouldn't make the UI any worse!

[db48x]

I‌ suppose we can go ahead and do this. I had been intending to investigate to find out where the extra spacing comes from, since it indicates to me that we are doing something wrong, but I‌ guess that working around it won’t make that any more difficult.

[CLIDragon]

I‌ suppose we can go ahead and do this. I had been intending to investigate to find out where the extra spacing comes from, since it indicates to me that we are doing something wrong, but I‌ guess that working around it won’t make that any more difficult.

Doesn't the extra spacing come from ItemSpacing?

And (separately), to handle this properly (though it is definitely scope creep), I suspect that ItemInnerSpacing, CellPadding, and possibly FramePadding will need to be handled (I think WindowPadding is already handled)

[db48x]

Sure, it apparently comes from ItemSpacing but if it’s supposed to be there why doesn’t CalcTextSize include it?

[CLIDragon]

Sure, it apparently comes from ItemSpacing but if it’s supposed to be there why doesn’t CalcTextSize include it?

That's easy, CalcTextSize only calculates the size of the text. See ocornut/imgui/issues/3714

[db48x]

The answer is not so simple. We were calculating the height as he recommends (“CalcTextSize(text).y + style.FramePadding.y * 2.0f for framed items”), but found that we need an additional style.ItemSpacing.y * 2.0f per line of text. If that’s intentional then why doesn’t CalcTextSize include it? I think it must be a bug in our code somewhere.

[RenechCDDA]

DB/CLIDragon if you want to reopen the linked issue around to track what's going on with the vertical spacing until you can really nail it, let me or other triage know. Whatever's easier for you to work on it