WIP: Rendering optimization: store rounded corners in texture to use 1 quad per corner (#1962) @franciscod

Version 1.71 + comments

Readme, comments, dear imgui prefixes

ImDrawListSplitter: Don't merge draw commands when crossing a VtxOffset boundary + Renamed fields ImDrawChannels to consistently suggest those are internal structures.

ImDrawListSplitter: Fix idx offset when merging (cef88f6) (#2591)

Internals: Added drawlist and color arg to RenderArrow(), RenderBullet(). Reordered args for RenderPixelEllipsis.

ImDrawListSplitter: Support merging consecutive draw commands straddling two channels. Support zero-init.

ImDrawListSplitter: extracted out of ImDrawList. Down the line we may obsolete the ImDrawList functions and encourage users to store the splitter aside, in the meanwhile ImDrawList holds a splitter. ...

(This will allow columns/table to recurse.)

ImDrawList: Fix broken channel splitting (another issue when the first channel is empty) (#2591) + fixed warnings with newer VS

Include <alloca.h> also when __SWITCH__ is defined (#2595) ...

Fixes compilation with devkitPro for Nintendo Switch

ImDrawList: Fix broken channel splitting (broken by d1e8b69) (#2591)

ImDrawList: Added ImDrawCmd::VtxOffset value to support large meshes (64k+ vertices) using 16-bits indices. To enable the feature, the renderer back-end needs to set 'io.BackendFlags |= ImGuiBackendFlags_HasVtxOffset' and honor the ImDrawCmd::VtxOffset field. Otherwise the value will always be zero. This has the advantage of preserving smaller index buffers and allowing to execute on hardware that do not support 32-bits indices. ...

ImDrawList: Added ImDrawCmd::IdxOffset value, equivalent to summing element count for each draw command. This is provided for convenience and consistency with VtxOffset. (#2591)

ImDrawList: Store initial flags for the frame in ImDrawListSharedData, reducing code duplication in setting up the flags.

ImFontGlyphRangesBuilder: Fixed unnecessarily over-sized buffer, which incidentally was also not fully cleared. Fixed edge case overflow when adding character 0xFFFF. (#2568)

Fixed GCC mem-access warnings (#2565) ...

+ using "if defined" more consistently for Clang.

Fix undefined behavior (#2561)

Version 1.71 WIP + fixed minor typo

Version 1.70

Amend 48a09a7 with changelog, breaking changes, tweak demo code for spacing. (#2518)

Improved algorithm for mitre joints on thick lines

Misc: Added IM_MALLOC/IM_FREE macros mimicking IM_NEW/IM_DELETE so user doesn't need to revert to using the ImGui::MemAlloc()/MemFree() calls directly.

InputText: Made Shift+Tab consistently do nothing regardless of whether the back-end emits both char and keys or just keys. (#2467, #1336)

Silencing -Wstack-protector (#2459)

Comments, todo list, remove trailing spaces.

Version 1.70 WIP

Version 1.69, comments, typos

Added GetGlyphRangesVietnamese() helper. (#2403)

Fix typos. (#2413)

Fix -Wconversion warning (#2379) ...

The warning was caused by implicit conversion from pointer type which
NULL has to non-pointer type, e.g. if ImTextureID is long int

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