Plot: Fixed error in 5e3a1de (#2387)

Plot: Fixed divide-by-zero in PlotLines() when passing a count of 1. (#2387) [@Lectem]

InputText: Fixed various display corruption related to swapping the underlying buffer while a input widget is active (both for writable and read-only paths). Often they would manifest when manipulating the scrollbar of a multi-line input text.

Internal: InputText: Minor changes (intended to have side-effect but clarify next commit, however there is rarely such a thing as zero side effect in InputText land!)

InputText; Disabled rendering selection when inactive (it kinda work but I'm not sure this is desirable especially for single-line input, was not intended to be active).

InputText: Fixed deactivated but-last-active InputText instance holding on displaying the last active version of the text and not reflecting change in the source. Fix/amend 2e9a175. [+test]

Log/Capture: Fixed LogXXX functions 'auto_open_depth' parameter being treated as an absolute tree depth instead of a relative one. Fixed CollapsingHeader trailing ascii representation being "#" instead of "##". Minor tidying up the of code.

TabBar: Added extra mis-usage error recovery. Past the assert, common mis-usage don't lead to hard crashes any more, facilitating integration with scripting languages. (#1651)

TabBar: Fixed a crash when using BeginTabBar() recursively (didn't affect docking). (#2371) ...

Added ImPool::Contains() helper.

Internal: InputText: Tweaks (including a large indentation change, compare ignoring space) to make next commit more digestible.

Internal: InputText: refactor the flow to easily decorrelate rendering of selection vs cursor, which would allow us to render selection on inactive items, and generally makes the code clearer. + Some renaming.

Internal: InputText: Made clipboard copy/cut use its own temporary buffer (like paste) so we can guarantee that TempBuffer if not altered and can be preserved. Renamed TempBufferA to TextA to celebrate this.

Internal: InputText: Renamed is_editable to !is_readonly, Hopefully more explicit. Renamed internal member. Shuffled some code. Added comments, assert (_will_ trigger on !readonly > readonly edge, old bug).

InputText: Fixed an edge case crash that would happen if another widget sharing the same ID is being swapped with an InputText that has yet to be activated.

Internal: InputText: Refactor to clarify access pattern to the InputTextState (we are now accessing via a pointer which can be NULL, shortened its name while we are at it) + added an assert to track an issue that existed already before.

Internal: InputText: Comments. Renamed internal member. Renamed ImGuiStb->ImStb.

InputText: Renamed some local variables to clarify code. Should be a no-op functionality wise. TODO items.

InputInt, InputFloat, InputScalar: Fix to keep the label of the +/- buttons centered when style.FramePadding.x is abnormally larger than style.FramePadding.y. Since the buttons are meant to be square (to align with e.g. color button) we always use FramePadding.y. (#2367)

Version 1.69 WIP

Internal: Changed Scrollbar() signature. Using GetScrollbarID() in InputTextMultiline(). ...

Removed multiple semi-colons (#2368)

Fixed unused argument warning when compiling with IM_ASERT() evaluating to an empty macro.

Version 1.68

Selectable: add support for specifying text alignment on selectables (#2347) ...

Adds a style variable to Selectable that allows clients to specify the
text alignment within Selectables, adds a section in the demo to
demonstrate selectable text alignment, and a pair of sliders in the
style editor to change selectable alignment on the fly.

In terms of implementation, this one is extremely simple: Selectable was
already calling an API that supports text alignment, but had hard-coded
it to top-left. This changes that to just pass the style variable
straight through to RenderTextClipped. Backwards-compatibility is
preserved by defaulting the text_align parameter to (0, 0), i.e.,
top-left.

This also fixes a bug with selectable text rendering that caused
right-aligned text in a selectable to be clipped incorrectly, because
the wrong clipping rectangle was being used.

Scrollbar: Fade out and disable interaction when too small, in order to facilitate using the resize grab on very small window, as well as reducing visual noise/overlap. (+1 squashed commits) ...

Internals: Added GetScrollbarID(). (#1185)

Shallow tweaks

Tabs: Fixed border (when enabled) so it is aligned correctly mid-pixel and appears as bright as other borders.

ListBox/InputTextMultiline: Better optimized when clipped / non-visible.

DragScalarN, SliderScalarN, InputScalarN: Removed unnecessary string id after the integer PushID() calls.

Minor tweaks to reduce false positive of PVS Studio static analyzer.

Menus: Tweaked horizontal overlap between parent and child menu (to help convey relative depth) from using style.ItemSpacing.x to style.ItemInnerSpacing.x, the later being expected to be smaller. (#1086)