Squashed commit of the following:

commit 5884219
Author: cfillion <[email protected]>
Date:   Wed Sep 28 23:37:39 2022 -0400

    imgui_freetype: Assert if bitmap size exceed chunk size to avoid buffer overflow. (ocornut#5731)

commit f2a522d
Author: ocornut <[email protected]>
Date:   Fri Sep 30 15:43:27 2022 +0200

    ImDrawList: Not using alloca() anymore, lift single polygon size limits. (ocornut#5704, ocornut#1811)

commit cc5058e
Author: ocornut <[email protected]>
Date:   Thu Sep 29 21:59:32 2022 +0200

    IO: Filter duplicate input events during the AddXXX() calls. (ocornut#5599, ocornut#4921)

commit fac8295
Author: ocornut <[email protected]>
Date:   Thu Sep 29 21:31:36 2022 +0200

    IO: remove ImGuiInputEvent::IgnoredAsSame (revert part of 839c310), will filter earlier in next commit. (ocornut#5599)

    Making it a separate commit as this leads to much indentation change.

commit 9e7f460
Author: ocornut <[email protected]>
Date:   Thu Sep 29 20:42:45 2022 +0200

    Fixed GetKeyName() for ImGuiMod_XXX values, made invalid MousePos display in log nicer.  (ocornut#4921, ocornut#456)

    Amend fd408c9

commit 0749453
Author: ocornut <[email protected]>
Date:   Thu Sep 29 19:51:54 2022 +0200

    Menus, Nav: Fixed not being able to close a menu with Left arrow when parent is not a popup. (ocornut#5730)

commit 9f6aae3
Author: ocornut <[email protected]>
Date:   Thu Sep 29 19:48:27 2022 +0200

    Nav: Fixed race condition pressing Esc during popup opening frame causing crash.

commit bd2355a
Author: ocornut <[email protected]>
Date:   Thu Sep 29 19:25:26 2022 +0200

    Menus, Nav: Fixed using left/right navigation when appending to an existing menu (multiple BeginMenu() call with same names). (ocornut#1207)

commit 3532ed1
Author: ocornut <[email protected]>
Date:   Thu Sep 29 18:07:35 2022 +0200

    Menus, Nav: Fixed keyboard/gamepad navigation occasionally erroneously landing on menu-item in parent when the parent is not a popup. (ocornut#5730)

    Replace BeginMenu/MenuItem swapping g.NavWindow with a more adequate ImGuiItemFlags_NoWindowHoverableCheck.
    Expecting more subtle issues to stem from this.
    Note that NoWindowHoverableCheck is not supported by IsItemHovered() but then IsItemHovered() on BeginMenu() never worked: fix should be easy in BeginMenu() + add test is IsItemHovered(), will do later

commit d5d7050
Author: ocornut <[email protected]>
Date:   Thu Sep 29 17:26:52 2022 +0200

    Various comments

    As it turns out, functions like IsItemHovered() won't work on an open BeginMenu() because LastItemData is overriden by BeginPopup(). Probably an easy fix.

commit e74a50f
Author: Andrew D. Zonenberg <[email protected]>
Date:   Wed Sep 28 08:19:34 2022 -0700

    Added GetGlyphRangesGreek() helper for Greek & Coptic glyph range. (ocornut#5676, ocornut#5727)

commit d17627b
Author: ocornut <[email protected]>
Date:   Wed Sep 28 17:38:41 2022 +0200

    InputText: leave state->Flags uncleared for the purpose of backends emitting an on-screen keyboard for passwords. (ocornut#5724)

commit 0a7054c
Author: ocornut <[email protected]>
Date:   Wed Sep 28 17:00:45 2022 +0200

    Backends: Win32: Convert WM_CHAR values with MultiByteToWideChar() when window class was registered as MBCS (not Unicode). (ocornut#5725, ocornut#1807, ocornut#471, ocornut#2815, ocornut#1060)

commit a229a7f
Author: ocornut <[email protected]>
Date:   Wed Sep 28 16:57:09 2022 +0200

    Examples: Win32: Always use RegisterClassW() to ensure windows are Unicode. (ocornut#5725)

commit e0330c1
Author: ocornut <[email protected]>
Date:   Wed Sep 28 14:54:38 2022 +0200

    Fonts, Text: Fixed wrapped-text not doing a fast-forward on lines above the clipping region. (ocornut#5720)

    which would result in an abnormal number of vertices created.

commit 4d4889b
Author: ocornut <[email protected]>
Date:   Wed Sep 28 12:42:06 2022 +0200

    Refactor CalcWordWrapPositionA() to take on the responsability of minimum character display. Add CalcWordWrapNextLineStartA(), simplify caller code.

    Should be no-op but incrementing IMGUI_VERSION_NUM just in case.
    Preparing for ocornut#5720

commit 5c4426c
Author: ocornut <[email protected]>
Date:   Wed Sep 28 12:22:34 2022 +0200

    Demo: Fixed Log & Console from losing scrolling position with Auto-Scroll when child is clipped. (ocornut#5721)

commit 12c0246
Author: ocornut <[email protected]>
Date:   Wed Sep 28 12:07:43 2022 +0200

    Removed support for 1.42-era IMGUI_DISABLE_INCLUDE_IMCONFIG_H / IMGUI_INCLUDE_IMCONFIG_H. (ocornut#255)

commit 73efcec
Author: ocornut <[email protected]>
Date:   Tue Sep 27 22:21:47 2022 +0200

    Examples: disable GL related warnings on Mac + amend to ignore list.

commit a725db1
Author: ocornut <[email protected]>
Date:   Tue Sep 27 18:47:20 2022 +0200

    Comments for flags discoverability + add to debug log (ocornut#3795, ocornut#4559)

commit 325299f
Author: ocornut <[email protected]>
Date:   Wed Sep 14 15:46:27 2022 +0200

    Backends: OpenGL: Add ability to #define IMGUI_IMPL_OPENGL_DEBUG. (ocornut#4468, ocornut#4825, ocornut#4832, ocornut#5127, ocornut#5655, ocornut#5709)

commit 56c3eae
Author: ocornut <[email protected]>
Date:   Tue Sep 27 14:24:21 2022 +0200

    ImDrawList: asserting on incorrect value for CurveTessellationTol (ocornut#5713)

commit 04316bd
Author: ocornut <[email protected]>
Date:   Mon Sep 26 16:32:09 2022 +0200

    ColorEdit3: fixed id collision leading to an assertion. (ocornut#5707)

commit c261dac
Author: ocornut <[email protected]>
Date:   Mon Sep 26 14:50:46 2022 +0200

    Demo: moved ShowUserGuide() lower in the file, to make main demo entry point more visible + fix using IMGUI_DEBUG_LOG() macros in if/else.

commit 51bbc70
Author: ocornut <[email protected]>
Date:   Mon Sep 26 14:44:26 2022 +0200

    Backends: SDL: Disable SDL 2.0.22 new "auto capture" which prevents drag and drop across windows, and don't capture mouse when drag and dropping. (ocornut#5710)

commit 7a9045d
Author: ocornut <[email protected]>
Date:   Mon Sep 26 11:55:07 2022 +0200

    Backends: WGPU: removed Emscripten version check (currently failing on CI, ensure why, and tbh its redundant/unnecessary with changes of wgpu api nowadays)

commit 83a0030
Author: ocornut <[email protected]>
Date:   Mon Sep 26 10:33:44 2022 +0200

    Added ImGuiMod_Shortcut which is ImGuiMod_Super on Mac and ImGuiMod_Ctrl otherwise. (ocornut#456)

commit fd408c9
Author: ocornut <[email protected]>
Date:   Thu Sep 22 18:58:33 2022 +0200

    Renamed and merged keyboard modifiers key enums and flags into a same set:. ImGuiKey_ModXXX -> ImGuiMod_XXX and ImGuiModFlags_XXX -> ImGuiMod_XXX. (ocornut#4921, ocornut#456)

    Changed signature of GetKeyChordName() to use ImGuiKeyChord.
    Additionally SetActiveIdUsingAllKeyboardKeys() doesn't set ImGuiKey_ModXXX but we never need/use those and the system will be changed in upcoming commits.

# Conflicts:
#	docs/CHANGELOG.txt
#	imgui.h
#	imgui_demo.cpp

docs/CHANGELOG.txt

@@ -148,6 +148,7 @@ Other Changes:
   which would result in an abnormal number of vertices created (was slower and more likely to
   asserts with 16-bits ImDrawVtx). (#5720)
 - Fonts: Added GetGlyphRangesGreek() helper for Greek & Coptic glyph range. (#5676, #5727) [@azonenberg]
+- ImDrawList: Not using alloca() anymore, lift single polygon size limits. (#5704, #1811)
 - Platform IME: [Windows] Removed call to ImmAssociateContextEx() leading to freeze on some setups.
   (#2589, #5535, #5264, #4972)
 - Misc: ImGuiKey is now a typed enum, allowing ImGuiKey_XXX symbols to be named in debuggers. (#4921)

imgui.cpp

@@ -4737,6 +4737,7 @@ void ImGui::Shutdown()
         IM_DELETE(g.IO.Fonts);
     }
     g.IO.Fonts = NULL;
+    g.DrawListSharedData.TempBuffer.clear();
 
     // Cleanup of other data are conditional on actually having initialized Dear ImGui.
     if (!g.Initialized)

imgui.h

@@ -23,7 +23,7 @@
 // Library Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals, e.g. '#if IMGUI_VERSION_NUM > 12345')
 #define IMGUI_VERSION               "1.89 WIP"
-#define IMGUI_VERSION_NUM           18828
+#define IMGUI_VERSION_NUM           18829
 #define IMGUI_HAS_TABLE
 
 /*
@@ -2513,7 +2513,7 @@ struct ImDrawList
 
     // [Internal, used while building lists]
     unsigned int            _VtxCurrentIdx;     // [Internal] generally == VtxBuffer.Size unless we are past 64K vertices, in which case this gets reset to 0.
-    const ImDrawListSharedData* _Data;          // Pointer to shared draw data (you can use ImGui::GetDrawListSharedData() to get the one from current ImGui context)
+    ImDrawListSharedData*   _Data;              // Pointer to shared draw data (you can use ImGui::GetDrawListSharedData() to get the one from current ImGui context)
     const char*             _OwnerName;         // Pointer to owner window's name for debugging
     ImDrawVert*             _VtxWritePtr;       // [Internal] point within VtxBuffer.Data after each add command (to avoid using the ImVector<> operators too much)
     ImDrawIdx*              _IdxWritePtr;       // [Internal] point within IdxBuffer.Data after each add command (to avoid using the ImVector<> operators too much)
@@ -2525,7 +2525,7 @@ struct ImDrawList
     float                   _FringeScale;       // [Internal] anti-alias fringe is scaled by this value, this helps to keep things sharp while zooming at vertex buffer content
 
     // If you want to create ImDrawList instances, pass them ImGui::GetDrawListSharedData() or create and use your own ImDrawListSharedData (so you can use ImDrawList without ImGui)
-    ImDrawList(const ImDrawListSharedData* shared_data) { memset(this, 0, sizeof(*this)); _Data = shared_data; }
+    ImDrawList(ImDrawListSharedData* shared_data) { memset(this, 0, sizeof(*this)); _Data = shared_data; }
 
     ~ImDrawList() { _ClearFreeMemory(); }
     IMGUI_API void  PushClipRect(const ImVec2& clip_rect_min, const ImVec2& clip_rect_max, bool intersect_with_current_clip_rect = false);  // Render-level scissoring. This is passed down to your render function but not used for CPU-side coarse clipping. Prefer using higher-level ImGui::PushClipRect() to affect logic (hit-testing and widget culling)

imgui_draw.cpp

@@ -39,25 +39,12 @@ Index of this file:
 #endif
 
 #include <stdio.h>      // vsnprintf, sscanf, printf
-#if !defined(alloca)
-#if defined(__GLIBC__) || defined(__sun) || defined(__APPLE__) || defined(__NEWLIB__)
-#include <alloca.h>     // alloca (glibc uses <alloca.h>. Note that Cygwin may have _WIN32 defined, so the order matters here)
-#elif defined(_WIN32)
-#include <malloc.h>     // alloca
-#if !defined(alloca)
-#define alloca _alloca  // for clang with MS Codegen
-#endif
-#else
-#include <stdlib.h>     // alloca
-#endif
-#endif
 
 // Visual Studio warnings
 #ifdef _MSC_VER
 #pragma warning (disable: 4127)     // condition expression is constant
 #pragma warning (disable: 4505)     // unreferenced local function has been removed (stb stuff)
 #pragma warning (disable: 4996)     // 'This function or variable may be unsafe': strcpy, strdup, sprintf, vsnprintf, sscanf, fopen
-#pragma warning (disable: 6255)     // [Static Analyzer] _alloca indicates failure by raising a stack overflow exception.  Consider using _malloca instead.
 #pragma warning (disable: 26451)    // [Static Analyzer] Arithmetic overflow : Using operator 'xxx' on a 4 byte value and then casting the result to a 8 byte value. Cast the value to the wider type before calling operator 'xxx' to avoid overflow(io.2).
 #pragma warning (disable: 26812)    // [Static Analyzer] The enum type 'xxx' is unscoped. Prefer 'enum class' over 'enum' (Enum.3). [MSVC Static Analyzer)
 #endif
@@ -67,9 +54,6 @@ Index of this file:
 #if __has_warning("-Wunknown-warning-option")
 #pragma clang diagnostic ignored "-Wunknown-warning-option"         // warning: unknown warning group 'xxx'                      // not all warnings are known by all Clang versions and they tend to be rename-happy.. so ignoring warnings triggers new warnings on some configuration. Great!
 #endif
-#if __has_warning("-Walloca")
-#pragma clang diagnostic ignored "-Walloca"                         // warning: use of function '__builtin_alloca' is discouraged
-#endif
 #pragma clang diagnostic ignored "-Wunknown-pragmas"                // warning: unknown warning group 'xxx'
 #pragma clang diagnostic ignored "-Wold-style-cast"                 // warning: use of old-style cast                            // yes, they are more terse.
 #pragma clang diagnostic ignored "-Wfloat-equal"                    // warning: comparing floating point with == or != is unsafe // storing and comparing against same constants ok.
@@ -753,7 +737,8 @@ void ImDrawList::AddPolyline(const ImVec2* points, const int points_count, ImU32
 
         // Temporary buffer
         // The first <points_count> items are normals at each line point, then after that there are either 2 or 4 temp points for each line point
-        ImVec2* temp_normals = (ImVec2*)alloca(points_count * ((use_texture || !thick_line) ? 3 : 5) * sizeof(ImVec2)); //-V630
+        _Data->TempBuffer.reserve_discard(points_count * ((use_texture || !thick_line) ? 3 : 5));
+        ImVec2* temp_normals = _Data->TempBuffer.Data;
         ImVec2* temp_points = temp_normals + points_count;
 
         // Calculate normals (tangents) for each line segment
@@ -1001,7 +986,8 @@ void ImDrawList::AddConvexPolyFilled(const ImVec2* points, const int points_coun
         }
 
         // Compute normals
-        ImVec2* temp_normals = (ImVec2*)alloca(points_count * sizeof(ImVec2)); //-V630
+        _Data->TempBuffer.reserve_discard(points_count);
+        ImVec2* temp_normals = _Data->TempBuffer.Data;
         for (int i0 = points_count - 1, i1 = 0; i1 < points_count; i0 = i1++)
         {
             const ImVec2& p0 = points[i0];

imgui_internal.h

@@ -734,6 +734,9 @@ struct IMGUI_API ImDrawListSharedData
     ImVec4          ClipRectFullscreen;         // Value for PushClipRectFullscreen()
     ImDrawListFlags InitialFlags;               // Initial flags at the beginning of the frame (it is possible to alter flags on a per-drawlist basis afterwards)
 
+    // [Internal] Temp write buffer
+    ImVector<ImVec2> TempBuffer;
+
     // [Internal] Lookup tables
     ImVec2          ArcFastVtx[IM_DRAWLIST_ARCFAST_TABLE_SIZE]; // Sample points on the quarter of the circle.
     float           ArcFastRadiusCutoff;                        // Cutoff radius after which arc drawing will fallback to slower PathArcTo()

misc/freetype/imgui_freetype.cpp

@@ -508,7 +508,7 @@ bool ImFontAtlasBuildWithFreeTypeEx(FT_Library ft_library, ImFontAtlas* atlas, u
     // Allocate temporary rasterization data buffers.
     // We could not find a way to retrieve accurate glyph size without rendering them.
     // (e.g. slot->metrics->width not always matching bitmap->width, especially considering the Oblique transform)
-    // We allocate in chunks of 256 KB to not waste too much extra memory ahead. Hopefully users of FreeType won't find the temporary allocations.
+    // We allocate in chunks of 256 KB to not waste too much extra memory ahead. Hopefully users of FreeType won't mind the temporary allocations.
     const int BITMAP_BUFFERS_CHUNK_SIZE = 256 * 1024;
     int buf_bitmap_current_used_bytes = 0;
     ImVector<unsigned char*> buf_bitmap_buffers;
@@ -556,6 +556,7 @@ bool ImFontAtlasBuildWithFreeTypeEx(FT_Library ft_library, ImFontAtlas* atlas, u
                 buf_bitmap_current_used_bytes = 0;
                 buf_bitmap_buffers.push_back((unsigned char*)IM_ALLOC(BITMAP_BUFFERS_CHUNK_SIZE));
             }
+            IM_ASSERT(buf_bitmap_current_used_bytes + bitmap_size_in_bytes <= BITMAP_BUFFERS_CHUNK_SIZE); // We could probably allocate custom-sized buffer instead.
 
             // Blit rasterized pixels to our temporary buffer and keep a pointer to it.
             src_glyph.BitmapData = (unsigned int*)(buf_bitmap_buffers.back() + buf_bitmap_current_used_bytes);