Update imgui to 1.81 + docking.

1 files changed, 117 insertions, 85 deletions

diff --git a/imgui/imgui.h b/imgui/imgui.h
index 29b0d5a2..48b71756 100644
--- a/imgui/imgui.h
+++ b/imgui/imgui.h
@@ -1,4 +1,4 @@
-// dear imgui, v1.80
+// dear imgui, v1.81
 // (headers)
 
 // Help:
@@ -31,7 +31,8 @@ Index of this file:
 // [SECTION] Helpers (ImGuiOnceUponAFrame, ImGuiTextFilter, ImGuiTextBuffer, ImGuiStorage, ImGuiListClipper, ImColor)
 // [SECTION] Drawing API (ImDrawCallback, ImDrawCmd, ImDrawIdx, ImDrawVert, ImDrawChannel, ImDrawListSplitter, ImDrawListFlags, ImDrawList, ImDrawData)
 // [SECTION] Font API (ImFontConfig, ImFontGlyph, ImFontGlyphRangesBuilder, ImFontAtlasFlags, ImFontAtlas, ImFont)
-// [SECTION] Platform interface for multi-viewport support (ImGuiPlatformIO, ImGuiPlatformMonitor, ImGuiViewportFlags, ImGuiViewport)
+// [SECTION] Viewports (ImGuiViewportFlags, ImGuiViewport)
+// [SECTION] Platform interface for multi-viewport support (ImGuiPlatformIO, ImGuiPlatformMonitor)
 
 */
 
@@ -59,8 +60,8 @@ Index of this file:
 
 // Version
 // (Integer encoded as XYYZZ for use in #if preprocessor conditionals. Work in progress versions typically starts at XYY99 then bounce up to XYY00, XYY01 etc. when release tagging happens)
-#define IMGUI_VERSION               "1.80"
-#define IMGUI_VERSION_NUM           18000
+#define IMGUI_VERSION               "1.81"
+#define IMGUI_VERSION_NUM           18100
 #define IMGUI_CHECKVERSION()        ImGui::DebugCheckVersionAndDataLayout(IMGUI_VERSION, sizeof(ImGuiIO), sizeof(ImGuiStyle), sizeof(ImVec2), sizeof(ImVec4), sizeof(ImDrawVert), sizeof(ImDrawIdx))
 #define IMGUI_HAS_TABLE
 #define IMGUI_HAS_VIEWPORT          // Viewport WIP branch
@@ -128,6 +129,7 @@ struct ImDrawListSplitter;          // Helper to split a draw list into differen
 struct ImDrawVert;                  // A single vertex (pos + uv + col = 20 bytes by default. Override layout with IMGUI_OVERRIDE_DRAWVERT_STRUCT_LAYOUT)
 struct ImFont;                      // Runtime data for a single font within a parent ImFontAtlas
 struct ImFontAtlas;                 // Runtime data for multiple fonts, bake multiple fonts into a single texture, TTF/OTF font loader
+struct ImFontBuilderIO;             // Opaque interface to a font builder (stb_truetype or FreeType).
 struct ImFontConfig;                // Configuration data when adding a font or merging fonts
 struct ImFontGlyph;                 // A single font glyph (code point + coordinates within in ImFontAtlas + offset)
 struct ImFontGlyphRangesBuilder;    // Helper to build glyph ranges from text/string data
@@ -147,7 +149,7 @@ struct ImGuiTableSortSpecs;         // Sorting specifications for a table (often
 struct ImGuiTableColumnSortSpecs;   // Sorting specification for one column of a table
 struct ImGuiTextBuffer;             // Helper to hold and append into a text buffer (~string builder)
 struct ImGuiTextFilter;             // Helper to parse and apply text filters (e.g. "aaaaa[,bbbbb][,ccccc]")
-struct ImGuiViewport;               // Viewport (generally ~1 per window to output to at the OS level. Need per-platform support to use multiple viewports)
+struct ImGuiViewport;               // A Platform Window (always 1 unless multi-viewport are enabled. One per platform window to output to). In the future may represent Platform Monitor
 struct ImGuiWindowClass;            // Window class (rare/advanced uses: provide hints to the platform backend via altered viewport flags and parent/child info)
 
 // Enums/Flags (declared as int for compatibility with old C++, to allow using as flags and to not pollute the top of this file)
@@ -325,11 +327,11 @@ namespace ImGui
     IMGUI_API bool          IsWindowHovered(ImGuiHoveredFlags flags=0); // is current window hovered (and typically: not blocked by a popup/modal)? see flags for options. NB: If you are trying to check whether your mouse should be dispatched to imgui or to your app, you should use the 'io.WantCaptureMouse' boolean for that! Please read the FAQ!
     IMGUI_API ImDrawList*   GetWindowDrawList();                        // get draw list associated to the current window, to append your own drawing primitives
     IMGUI_API float         GetWindowDpiScale();                        // get DPI scale currently associated to the current window's viewport.
-    IMGUI_API ImGuiViewport*GetWindowViewport();                        // get viewport currently associated to the current window.
     IMGUI_API ImVec2        GetWindowPos();                             // get current window position in screen space (useful if you want to do your own drawing via the DrawList API)
     IMGUI_API ImVec2        GetWindowSize();                            // get current window size
     IMGUI_API float         GetWindowWidth();                           // get current window width (shortcut for GetWindowSize().x)
     IMGUI_API float         GetWindowHeight();                          // get current window height (shortcut for GetWindowSize().y)
+    IMGUI_API ImGuiViewport*GetWindowViewport();                        // get viewport currently associated to the current window.
 
     // Prefer using SetNextXXX functions (before Begin) rather that SetXXX functions (after Begin).
     IMGUI_API void          SetNextWindowPos(const ImVec2& pos, ImGuiCond cond = 0, const ImVec2& pivot = ImVec2(0, 0)); // set next window position. call before Begin(). use pivot=(0.5f,0.5f) to center on given point, etc.
@@ -386,7 +388,7 @@ namespace ImGui
     IMGUI_API void          PopButtonRepeat();
 
     // Parameters stacks (current window)
-    IMGUI_API void          PushItemWidth(float item_width);                                // push width of items for common large "item+label" widgets. >0.0f: width in pixels, <0.0f align xx pixels to the right of window (so -FLT_MIN always align width to the right side). 0.0f = default to ~2/3 of windows width,
+    IMGUI_API void          PushItemWidth(float item_width);                                // push width of items for common large "item+label" widgets. >0.0f: width in pixels, <0.0f align xx pixels to the right of window (so -FLT_MIN always align width to the right side).
     IMGUI_API void          PopItemWidth();
     IMGUI_API void          SetNextItemWidth(float item_width);                             // set width of the _next_ common large "item+label" widget. >0.0f: width in pixels, <0.0f align xx pixels to the right of window (so -FLT_MIN always align width to the right side)
     IMGUI_API float         CalcItemWidth();                                                // width of item given pushed settings and current cursor position. NOT necessarily the width of last item unlike most 'Item' functions.
@@ -425,8 +427,8 @@ namespace ImGui
     IMGUI_API void          SetCursorPosX(float local_x);                                   //    GetWindowPos() + GetCursorPos() == GetCursorScreenPos() etc.)
     IMGUI_API void          SetCursorPosY(float local_y);                                   //
     IMGUI_API ImVec2        GetCursorStartPos();                                            // initial cursor position in window coordinates
-    IMGUI_API ImVec2        GetCursorScreenPos();                                           // cursor position in absolute screen coordinates (0..io.DisplaySize) or natural OS coordinates when using multiple viewport. Useful to work with ImDrawList API.
-    IMGUI_API void          SetCursorScreenPos(const ImVec2& pos);                          // cursor position in absolute screen coordinates (0..io.DisplaySize) or natural OS coordinates when using multiple viewport.
+    IMGUI_API ImVec2        GetCursorScreenPos();                                           // cursor position in absolute coordinates (useful to work with ImDrawList API). generally top-left == GetMainViewport()->Pos == (0,0) in single viewport mode, and bottom-right == GetMainViewport()->Pos+Size == io.DisplaySize in single-viewport mode.
+    IMGUI_API void          SetCursorScreenPos(const ImVec2& pos);                          // cursor position in absolute coordinates
     IMGUI_API void          AlignTextToFramePadding();                                      // vertically align upcoming text baseline to FramePadding.y so that it will align properly to regularly framed items (call if you have text on a line before a framed item)
     IMGUI_API float         GetTextLineHeight();                                            // ~ FontSize
     IMGUI_API float         GetTextLineHeightWithSpacing();                                 // ~ FontSize + style.ItemSpacing.y (distance in pixels between 2 consecutive lines of text)
@@ -483,7 +485,7 @@ namespace ImGui
 
     // Widgets: Combo Box
     // - The BeginCombo()/EndCombo() api allows you to manage your contents and selection state however you want it, by creating e.g. Selectable() items.
-    // - The old Combo() api are helpers over BeginCombo()/EndCombo() which are kept available for convenience purpose.
+    // - The old Combo() api are helpers over BeginCombo()/EndCombo() which are kept available for convenience purpose. This is analogous to how ListBox are created.
     IMGUI_API bool          BeginCombo(const char* label, const char* preview_value, ImGuiComboFlags flags = 0);
     IMGUI_API void          EndCombo(); // only call EndCombo() if BeginCombo() returns true!
     IMGUI_API bool          Combo(const char* label, int* current_item, const char* const items[], int items_count, int popup_max_height_in_items = -1);
@@ -590,14 +592,18 @@ namespace ImGui
     IMGUI_API bool          Selectable(const char* label, bool* p_selected, ImGuiSelectableFlags flags = 0, const ImVec2& size = ImVec2(0, 0));      // "bool* p_selected" point to the selection state (read-write), as a convenient helper.
 
     // Widgets: List Boxes
-    // - FIXME: To be consistent with all the newer API, ListBoxHeader/ListBoxFooter should in reality be called BeginListBox/EndListBox. Will rename them.
+    // - This is essentially a thin wrapper to using BeginChild/EndChild with some stylistic changes.
+    // - The BeginListBox()/EndListBox() api allows you to manage your contents and selection state however you want it, by creating e.g. Selectable() or any items.
+    // - The simplified/old ListBox() api are helpers over BeginListBox()/EndListBox() which are kept available for convenience purpose. This is analoguous to how Combos are created.
+    // - Choose frame width:   size.x > 0.0f: custom  /  size.x < 0.0f or -FLT_MIN: right-align   /  size.x = 0.0f (default): use current ItemWidth
+    // - Choose frame height:  size.y > 0.0f: custom  /  size.y < 0.0f or -FLT_MIN: bottom-align  /  size.y = 0.0f (default): arbitrary default height which can fit ~7 items
+    IMGUI_API bool          BeginListBox(const char* label, const ImVec2& size = ImVec2(0, 0)); // open a framed scrolling region
+    IMGUI_API void          EndListBox();                                                       // only call EndListBox() if BeginListBox() returned true!
     IMGUI_API bool          ListBox(const char* label, int* current_item, const char* const items[], int items_count, int height_in_items = -1);
     IMGUI_API bool          ListBox(const char* label, int* current_item, bool (*items_getter)(void* data, int idx, const char** out_text), void* data, int items_count, int height_in_items = -1);
-    IMGUI_API bool          ListBoxHeader(const char* label, const ImVec2& size = ImVec2(0, 0)); // use if you want to reimplement ListBox() will custom data or interactions. if the function return true, you can output elements then call ListBoxFooter() afterwards.
-    IMGUI_API bool          ListBoxHeader(const char* label, int items_count, int height_in_items = -1); // "
-    IMGUI_API void          ListBoxFooter();                                                    // terminate the scrolling region. only call ListBoxFooter() if ListBoxHeader() returned true!
 
     // Widgets: Data Plotting
+    // - Consider using ImPlot (https://github.com/epezent/implot)
     IMGUI_API void          PlotLines(const char* label, const float* values, int values_count, int values_offset = 0, const char* overlay_text = NULL, float scale_min = FLT_MAX, float scale_max = FLT_MAX, ImVec2 graph_size = ImVec2(0, 0), int stride = sizeof(float));
     IMGUI_API void          PlotLines(const char* label, float(*values_getter)(void* data, int idx), void* data, int values_count, int values_offset = 0, const char* overlay_text = NULL, float scale_min = FLT_MAX, float scale_max = FLT_MAX, ImVec2 graph_size = ImVec2(0, 0));
     IMGUI_API void          PlotHistogram(const char* label, const float* values, int values_count, int values_offset = 0, const char* overlay_text = NULL, float scale_min = FLT_MAX, float scale_max = FLT_MAX, ImVec2 graph_size = ImVec2(0, 0), int stride = sizeof(float));
@@ -754,7 +760,7 @@ namespace ImGui
     // - Use DockSpace() to create an explicit dock node _within_ an existing window. See Docking demo for details.
     // - DockSpace() needs to be submitted _before_ any window they can host. If you use a dockspace, submit it early in your app.
     IMGUI_API void          DockSpace(ImGuiID id, const ImVec2& size = ImVec2(0, 0), ImGuiDockNodeFlags flags = 0, const ImGuiWindowClass* window_class = NULL);
-    IMGUI_API ImGuiID       DockSpaceOverViewport(ImGuiViewport* viewport = NULL, ImGuiDockNodeFlags flags = 0, const ImGuiWindowClass* window_class = NULL);
+    IMGUI_API ImGuiID       DockSpaceOverViewport(const ImGuiViewport* viewport = NULL, ImGuiDockNodeFlags flags = 0, const ImGuiWindowClass* window_class = NULL);
     IMGUI_API void          SetNextWindowDockID(ImGuiID dock_id, ImGuiCond cond = 0);           // set next window dock id (FIXME-DOCK)
     IMGUI_API void          SetNextWindowClass(const ImGuiWindowClass* window_class);           // set next window class (rare/advanced uses: provide hints to the platform backend via altered viewport flags and parent/child info)
     IMGUI_API ImGuiID       GetWindowDockID();
@@ -810,6 +816,12 @@ namespace ImGui
     IMGUI_API ImVec2        GetItemRectSize();                                                  // get size of last item
     IMGUI_API void          SetItemAllowOverlap();                                              // allow last item to be overlapped by a subsequent item. sometimes useful with invisible buttons, selectables, etc. to catch unused area.
 
+    // Viewports
+    // - Currently represents the Platform Window created by the application which is hosting our Dear ImGui windows.
+    // - In 'docking' branch with multi-viewport enabled, we extend this concept to have multiple active viewports.
+    // - In the future we will extend this concept further to also represent Platform Monitor and support a "no main platform window" operation mode.
+    IMGUI_API ImGuiViewport* GetMainViewport();                                                 // return primary/default viewport.
+
     // Miscellaneous Utilities
     IMGUI_API bool          IsRectVisible(const ImVec2& size);                                  // test if rectangle (of given size, starting from cursor position) is visible / not clipped.
     IMGUI_API bool          IsRectVisible(const ImVec2& rect_min, const ImVec2& rect_max);      // test if rectangle (in screen space) is visible / not clipped. to perform coarse clipping on user's side.
@@ -893,7 +905,7 @@ namespace ImGui
     // Read comments around the ImGuiPlatformIO structure for more details.
     // Note: You may use GetWindowViewport() to get the current viewport of the current window.
     IMGUI_API ImGuiPlatformIO&  GetPlatformIO();                                                // platform/renderer functions, for backend to setup + viewports list.
-    IMGUI_API ImGuiViewport*    GetMainViewport();                                              // main viewport. same as GetPlatformIO().MainViewport == GetPlatformIO().Viewports[0].
+    IMGUI_API ImGuiViewport*    GetMainViewport();                                              // return primary/default viewport. In the future in "no main platform window" mode we will direct this to primary monitor.
     IMGUI_API void              UpdatePlatformWindows();                                        // call in main loop. will call CreateWindow/ResizeWindow/etc. platform functions for each secondary viewport, and DestroyWindow for each inactive viewport.
     IMGUI_API void              RenderPlatformWindowsDefault(void* platform_render_arg = NULL, void* renderer_render_arg = NULL); // call in main loop. will call RenderWindow/SwapBuffers platform functions for each secondary viewport which doesn't have the ImGuiViewportFlags_Minimized flag set. May be reimplemented by user for custom rendering needs.
     IMGUI_API void              DestroyPlatformWindows();                                       // call DestroyWindow platform functions for all viewports. call from backend Shutdown() if you need to close platform windows before imgui shutdown. otherwise will be called by DestroyContext().
@@ -1128,7 +1140,7 @@ enum ImGuiTableFlags_
     ImGuiTableFlags_SizingFixedFit             = 1 << 13,  // Columns default to _WidthFixed or _WidthAuto (if resizable or not resizable), matching contents width.
     ImGuiTableFlags_SizingFixedSame            = 2 << 13,  // Columns default to _WidthFixed or _WidthAuto (if resizable or not resizable), matching the maximum contents width of all columns. Implicitly enable ImGuiTableFlags_NoKeepColumnsVisible.
     ImGuiTableFlags_SizingStretchProp          = 3 << 13,  // Columns default to _WidthStretch with default weights proportional to each columns contents widths.
-    ImGuiTableFlags_SizingStretchSame          = 4 << 13,  // Columns default to _WidthStretch with default weights all equal, unless overriden by TableSetupColumn().
+    ImGuiTableFlags_SizingStretchSame          = 4 << 13,  // Columns default to _WidthStretch with default weights all equal, unless overridden by TableSetupColumn().
     // Sizing Extra Options
     ImGuiTableFlags_NoHostExtendX              = 1 << 16,  // Make outer width auto-fit to columns, overriding outer_size.x value. Only available when ScrollX/ScrollY are disabled and Stretch columns are not used.
     ImGuiTableFlags_NoHostExtendY              = 1 << 17,  // Make outer height stop exactly at outer_size.y (prevent auto-extending table past the limit). Only available when ScrollX/ScrollY are disabled. Data below the limit will be clipped and not visible.
@@ -1806,7 +1818,7 @@ struct ImGuiIO
 
     ImGuiConfigFlags   ConfigFlags;             // = 0              // See ImGuiConfigFlags_ enum. Set by user/application. Gamepad/keyboard navigation options, etc.
     ImGuiBackendFlags  BackendFlags;            // = 0              // See ImGuiBackendFlags_ enum. Set by backend (imgui_impl_xxx files or custom backend) to communicate features supported by the backend.
-    ImVec2      DisplaySize;                    // <unset>          // Main display size, in pixels. This is for the default viewport.
+    ImVec2      DisplaySize;                    // <unset>          // Main display size, in pixels (generally == GetMainViewport()->Size)
     float       DeltaTime;                      // = 1.0f/60.0f     // Time elapsed since last frame, in seconds.
     float       IniSavingRate;                  // = 5.0f           // Minimum time between saving positions/sizes to .ini file, in seconds.
     const char* IniFilename;                    // = "imgui.ini"    // Path to .ini file. Set NULL to disable automatic .ini loading/saving, if e.g. you want to manually load/save from memory.
@@ -2064,6 +2076,10 @@ struct ImGuiTableSortSpecs
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
 namespace ImGui
 {
+    // OBSOLETED in 1.81 (from February 2021)
+    IMGUI_API bool      ListBoxHeader(const char* label, int items_count, int height_in_items = -1); // Helper to calculate size from items_count and height_in_items
+    static inline bool  ListBoxHeader(const char* label, const ImVec2& size = ImVec2(0, 0)) { return BeginListBox(label, size); }
+    static inline void  ListBoxFooter() { EndListBox(); }
     // OBSOLETED in 1.79 (from August 2020)
     static inline void  OpenPopupContextItem(const char* str_id = NULL, ImGuiMouseButton mb = 1) { OpenPopupOnItemClick(str_id, mb); } // Bool return value removed. Use IsWindowAppearing() in BeginPopup() instead. Renamed in 1.77, renamed back in 1.79. Sorry!
     // OBSOLETED in 1.78 (from June 2020)
@@ -2430,7 +2446,8 @@ enum ImDrawListFlags_
 // Each dear imgui window contains its own ImDrawList. You can use ImGui::GetWindowDrawList() to
 // access the current window draw list and draw custom primitives.
 // You can interleave normal ImGui:: calls and adding primitives to the current draw list.
-// All positions are generally in pixel coordinates (generally top-left at 0,0, bottom-right at io.DisplaySize, unless multiple viewports are used), but you are totally free to apply whatever transformation matrix to want to the data (if you apply such transformation you'll want to apply it to ClipRect as well)
+// In single viewport mode, top-left is == GetMainViewport()->Pos (generally 0,0), bottom-right is == GetMainViewport()->Pos+Size (generally io.DisplaySize).
+// You are totally free to apply whatever transformation matrix to want to the data (depending on the use of the transformation you may want to apply it to ClipRect as well!)
 // Important: Primitives are always added to the list and not culled (culling is done at higher-level by ImGui:: functions), if you use this API a lot consider coarse culling your drawn objects.
 struct ImDrawList
 {
@@ -2505,9 +2522,9 @@ struct ImDrawList
     inline    void  PathFillConvex(ImU32 col)                                   { AddConvexPolyFilled(_Path.Data, _Path.Size, col); _Path.Size = 0; }  // Note: Anti-aliased filling requires points to be in clockwise order.
     inline    void  PathStroke(ImU32 col, bool closed, float thickness = 1.0f)  { AddPolyline(_Path.Data, _Path.Size, col, closed, thickness); _Path.Size = 0; }
     IMGUI_API void  PathArcTo(const ImVec2& center, float radius, float a_min, float a_max, int num_segments = 10);
-    IMGUI_API void  PathArcToFast(const ImVec2& center, float radius, int a_min_of_12, int a_max_of_12);            // Use precomputed angles for a 12 steps circle
-    IMGUI_API void  PathBezierCubicCurveTo(const ImVec2& p2, const ImVec2& p3, const ImVec2& p4, int num_segments = 0);  // Cubic Bezier (4 control points)
-    IMGUI_API void  PathBezierQuadraticCurveTo(const ImVec2& p2, const ImVec2& p3, int num_segments = 0);                // Quadratic Bezier (3 control points)
+    IMGUI_API void  PathArcToFast(const ImVec2& center, float radius, int a_min_of_12, int a_max_of_12);                // Use precomputed angles for a 12 steps circle
+    IMGUI_API void  PathBezierCubicCurveTo(const ImVec2& p2, const ImVec2& p3, const ImVec2& p4, int num_segments = 0); // Cubic Bezier (4 control points)
+    IMGUI_API void  PathBezierQuadraticCurveTo(const ImVec2& p2, const ImVec2& p3, int num_segments = 0);               // Quadratic Bezier (3 control points)
     IMGUI_API void  PathRect(const ImVec2& rect_min, const ImVec2& rect_max, float rounding = 0.0f, ImDrawCornerFlags rounding_corners = ImDrawCornerFlags_All);
 
     // Advanced
@@ -2557,19 +2574,18 @@ struct ImDrawList
 struct ImDrawData
 {
     bool            Valid;                  // Only valid after Render() is called and before the next NewFrame() is called.
-    ImDrawList**    CmdLists;               // Array of ImDrawList* to render. The ImDrawList are owned by ImGuiContext and only pointed to from here.
     int             CmdListsCount;          // Number of ImDrawList* to render
     int             TotalIdxCount;          // For convenience, sum of all ImDrawList's IdxBuffer.Size
     int             TotalVtxCount;          // For convenience, sum of all ImDrawList's VtxBuffer.Size
-    ImVec2          DisplayPos;             // Upper-left position of the viewport to render (== upper-left of the orthogonal projection matrix to use)
-    ImVec2          DisplaySize;            // Size of the viewport to render (== io.DisplaySize for the main viewport) (DisplayPos + DisplaySize == lower-right of the orthogonal projection matrix to use)
+    ImDrawList**    CmdLists;               // Array of ImDrawList* to render. The ImDrawList are owned by ImGuiContext and only pointed to from here.
+    ImVec2          DisplayPos;             // Top-left position of the viewport to render (== top-left of the orthogonal projection matrix to use) (== GetMainViewport()->Pos for the main viewport, == (0.0) in most single-viewport applications)
+    ImVec2          DisplaySize;            // Size of the viewport to render (== GetMainViewport()->Size for the main viewport, == io.DisplaySize in most single-viewport applications)
     ImVec2          FramebufferScale;       // Amount of pixels for each unit of DisplaySize. Based on io.DisplayFramebufferScale. Generally (1,1) on normal display, (2,2) on OSX with Retina display.
     ImGuiViewport*  OwnerViewport;          // Viewport carrying the ImDrawData instance, might be of use to the renderer (generally not).
 
     // Functions
-    ImDrawData()    { Valid = false; Clear(); }
-    ~ImDrawData()   { Clear(); }
-    void Clear()    { Valid = false; CmdLists = NULL; CmdListsCount = TotalVtxCount = TotalIdxCount = 0; DisplayPos = DisplaySize = FramebufferScale = ImVec2(0.f, 0.f); OwnerViewport = NULL; } // The ImDrawList are owned by ImGuiContext!
+    ImDrawData()    { Clear(); }
+    void Clear()    { memset(this, 0, sizeof(*this)); }     // The ImDrawList are owned by ImGuiContext!
     IMGUI_API void  DeIndexAllBuffers();                    // Helper to convert all buffers from indexed to non-indexed, in case you cannot render indexed. Note: this is slow and most likely a waste of resources. Always prefer indexed rendering!
     IMGUI_API void  ScaleClipRects(const ImVec2& fb_scale); // Helper to scale the ClipRect field of each ImDrawCmd. Use if your final output buffer is at a different scale than Dear ImGui expects, or if there is a difference between your window resolution and framebuffer resolution.
 };
@@ -2585,8 +2601,8 @@ struct ImFontConfig
     bool            FontDataOwnedByAtlas;   // true     // TTF/OTF data ownership taken by the container ImFontAtlas (will delete memory itself).
     int             FontNo;                 // 0        // Index of font within TTF/OTF file
     float           SizePixels;             //          // Size in pixels for rasterizer (more or less maps to the resulting font height).
-    int             OversampleH;            // 3        // Rasterize at higher quality for sub-pixel positioning. Read https://github.com/nothings/stb/blob/master/tests/oversample/README.md for details.
-    int             OversampleV;            // 1        // Rasterize at higher quality for sub-pixel positioning. We don't use sub-pixel positions on the Y axis.
+    int             OversampleH;            // 3        // Rasterize at higher quality for sub-pixel positioning. Note the difference between 2 and 3 is minimal so you can reduce this to 2 to save memory. Read https://github.com/nothings/stb/blob/master/tests/oversample/README.md for details.
+    int             OversampleV;            // 1        // Rasterize at higher quality for sub-pixel positioning. This is not really useful as we don't use sub-pixel positions on the Y axis.
     bool            PixelSnapH;             // false    // Align every glyph to pixel boundary. Useful e.g. if you are merging a non-pixel aligned font with the default font. If enabled, you can set OversampleH/V to 1.
     ImVec2          GlyphExtraSpacing;      // 0, 0     // Extra spacing (in pixels) between glyphs. Only X axis is supported for now.
     ImVec2          GlyphOffset;            // 0, 0     // Offset all glyphs from this font input.
@@ -2594,7 +2610,7 @@ struct ImFontConfig
     float           GlyphMinAdvanceX;       // 0        // Minimum AdvanceX for glyphs, set Min to align font icons, set both Min/Max to enforce mono-space font
     float           GlyphMaxAdvanceX;       // FLT_MAX  // Maximum AdvanceX for glyphs
     bool            MergeMode;              // false    // Merge into previous ImFont, so you can combine multiple inputs font into one ImFont (e.g. ASCII font + icons + Japanese glyphs). You may want to use GlyphOffset.y when merge font of different heights.
-    unsigned int    RasterizerFlags;        // 0x00     // Settings for custom font rasterizer (e.g. ImGuiFreeType). Leave as zero if you aren't using one.
+    unsigned int    FontBuilderFlags;       // 0        // Settings for custom font builder. THIS IS BUILDER IMPLEMENTATION DEPENDENT. Leave as zero if unsure.
     float           RasterizerMultiply;     // 1.0f     // Brighten (>1.0f) or darken (<1.0f) font output. Brightening small fonts may be a good workaround to make them more readable.
     ImWchar         EllipsisChar;           // -1       // Explicitly specify unicode codepoint of ellipsis character. When fonts are being merged first specified ellipsis will be used.
 
@@ -2609,8 +2625,9 @@ struct ImFontConfig
 // (Note: some language parsers may fail to convert the 31+1 bitfield members, in this case maybe drop store a single u32 or we can rework this)
 struct ImFontGlyph
 {
-    unsigned int    Codepoint : 31;     // 0x0000..0xFFFF
-    unsigned int    Visible : 1;        // Flag to allow early out when rendering
+    unsigned int    Colored : 1;        // Flag to indicate glyph is colored and should generally ignore tinting (make it usable with no shift on little-endian as this is used in loops)
+    unsigned int    Visible : 1;        // Flag to indicate glyph has no visible pixels (e.g. space). Allow early out when rendering.
+    unsigned int    Codepoint : 30;     // 0x0000..0x10FFFF
     float           AdvanceX;           // Distance to next character (= data from font + ImFontConfig::GlyphExtraSpacing.x baked in)
     float           X0, Y0, X1, Y1;     // Glyph corners
     float           U0, V0, U1, V1;     // Texture coordinates
@@ -2754,6 +2771,10 @@ struct ImFontAtlas
     ImVector<ImFontConfig>      ConfigData;         // Configuration data
     ImVec4                      TexUvLines[IM_DRAWLIST_TEX_LINES_WIDTH_MAX + 1];  // UVs for baked anti-aliased lines
 
+    // [Internal] Font builder
+    const ImFontBuilderIO*      FontBuilderIO;      // Opaque interface to a font builder (default to stb_truetype, can be changed to use FreeType by defining IMGUI_ENABLE_FREETYPE).
+    unsigned int                FontBuilderFlags;   // Shared flags (for all fonts) for custom font builder. THIS IS BUILD IMPLEMENTATION DEPENDENT. Per-font override is also available in ImFontConfig.
+
     // [Internal] Packing data
     int                         PackIdMouseCursors; // Custom texture rectangle ID for white pixel and mouse cursors
     int                         PackIdLines;        // Custom texture rectangle ID for baked anti-aliased lines
@@ -2818,6 +2839,68 @@ struct ImFont
 };
 
 //-----------------------------------------------------------------------------
+// [SECTION] Viewports
+//-----------------------------------------------------------------------------
+
+// Flags stored in ImGuiViewport::Flags, giving indications to the platform backends.
+enum ImGuiViewportFlags_
+{
+    ImGuiViewportFlags_None                     = 0,
+    ImGuiViewportFlags_IsPlatformWindow         = 1 << 0,   // Represent a Platform Window
+    ImGuiViewportFlags_IsPlatformMonitor        = 1 << 1,   // Represent a Platform Monitor (unused yet)
+    ImGuiViewportFlags_OwnedByApp               = 1 << 2,   // Platform Window: is created/managed by the application (rather than a dear imgui backend)
+    ImGuiViewportFlags_NoDecoration             = 1 << 3,   // Platform Window: Disable platform decorations: title bar, borders, etc. (generally set all windows, but if ImGuiConfigFlags_ViewportsDecoration is set we only set this on popups/tooltips)
+    ImGuiViewportFlags_NoTaskBarIcon            = 1 << 4,   // Platform Window: Disable platform task bar icon (generally set on popups/tooltips, or all windows if ImGuiConfigFlags_ViewportsNoTaskBarIcon is set)
+    ImGuiViewportFlags_NoFocusOnAppearing       = 1 << 5,   // Platform Window: Don't take focus when created.
+    ImGuiViewportFlags_NoFocusOnClick           = 1 << 6,   // Platform Window: Don't take focus when clicked on.
+    ImGuiViewportFlags_NoInputs                 = 1 << 7,   // Platform Window: Make mouse pass through so we can drag this window while peaking behind it.
+    ImGuiViewportFlags_NoRendererClear          = 1 << 8,   // Platform Window: Renderer doesn't need to clear the framebuffer ahead (because we will fill it entirely).
+    ImGuiViewportFlags_TopMost                  = 1 << 9,   // Platform Window: Display on top (for tooltips only).
+    ImGuiViewportFlags_Minimized                = 1 << 10,  // Platform Window: Window is minimized, can skip render. When minimized we tend to avoid using the viewport pos/size for clipping window or testing if they are contained in the viewport.
+    ImGuiViewportFlags_NoAutoMerge              = 1 << 11,  // Platform Window: Avoid merging this window into another host window. This can only be set via ImGuiWindowClass viewport flags override (because we need to now ahead if we are going to create a viewport in the first place!).
+    ImGuiViewportFlags_CanHostOtherWindows      = 1 << 12   // Main viewport: can host multiple imgui windows (secondary viewports are associated to a single window).
+};
+
+// - Currently represents the Platform Window created by the application which is hosting our Dear ImGui windows.
+// - With multi-viewport enabled, we extend this concept to have multiple active viewports.
+// - In the future we will extend this concept further to also represent Platform Monitor and support a "no main platform window" operation mode.
+// - About Main Area vs Work Area:
+//   - Main Area = entire viewport.
+//   - Work Area = entire viewport minus sections used by main menu bars (for platform windows), or by task bar (for platform monitor).
+//   - Windows are generally trying to stay within the Work Area of their host viewport.
+struct ImGuiViewport
+{
+    ImGuiID             ID;                     // Unique identifier for the viewport
+    ImGuiViewportFlags  Flags;                  // See ImGuiViewportFlags_
+    ImVec2              Pos;                    // Main Area: Position of the viewport (Dear Imgui coordinates are the same as OS desktop/native coordinates)
+    ImVec2              Size;                   // Main Area: Size of the viewport.
+    ImVec2              WorkPos;                // Work Area: Position of the viewport minus task bars, menus bars, status bars (>= Pos)
+    ImVec2              WorkSize;               // Work Area: Size of the viewport minus task bars, menu bars, status bars (<= Size)
+    float               DpiScale;               // 1.0f = 96 DPI = No extra scale.
+    ImGuiID             ParentViewportId;       // (Advanced) 0: no parent. Instruct the platform backend to setup a parent/child relationship between platform windows.
+    ImDrawData*         DrawData;               // The ImDrawData corresponding to this viewport. Valid after Render() and until the next call to NewFrame().
+
+    // Our design separate the Renderer and Platform backends to facilitate combining default backends with each others.
+    // When our create your own backend for a custom engine, it is possible that both Renderer and Platform will be handled
+    // by the same system and you may not need to use all the UserData/Handle fields.
+    // The library never uses those fields, they are merely storage to facilitate backend implementation.
+    void*               RendererUserData;       // void* to hold custom data structure for the renderer (e.g. swap chain, framebuffers etc.). generally set by your Renderer_CreateWindow function.
+    void*               PlatformUserData;       // void* to hold custom data structure for the OS / platform (e.g. windowing info, render context). generally set by your Platform_CreateWindow function.
+    void*               PlatformHandle;         // void* for FindViewportByPlatformHandle(). (e.g. suggested to use natural platform handle such as HWND, GLFWWindow*, SDL_Window*)
+    void*               PlatformHandleRaw;      // void* to hold lower-level, platform-native window handle (e.g. the HWND) when using an abstraction layer like GLFW or SDL (where PlatformHandle would be a SDL_Window*)
+    bool                PlatformRequestMove;    // Platform window requested move (e.g. window was moved by the OS / host window manager, authoritative position will be OS window position)
+    bool                PlatformRequestResize;  // Platform window requested resize (e.g. window was resized by the OS / host window manager, authoritative size will be OS window size)
+    bool                PlatformRequestClose;   // Platform window requested closure (e.g. window was moved by the OS / host window manager, e.g. pressing ALT-F4)
+
+    ImGuiViewport()     { memset(this, 0, sizeof(*this)); }
+    ~ImGuiViewport()    { IM_ASSERT(PlatformUserData == NULL && RendererUserData == NULL); }
+
+    // Helpers
+    ImVec2              GetCenter() const       { return ImVec2(Pos.x + Size.x * 0.5f, Pos.y + Size.y * 0.5f); }
+    ImVec2              GetWorkCenter() const   { return ImVec2(WorkPos.x + WorkSize.x * 0.5f, WorkPos.y + WorkSize.y * 0.5f); }
+};
+
+//-----------------------------------------------------------------------------
 // [SECTION] Platform interface for multi-viewport support
 //-----------------------------------------------------------------------------
 // [BETA] (Optional) This is completely optional, for advanced users!
@@ -2925,7 +3008,6 @@ struct ImGuiPlatformIO
 
     // Viewports list (the list is updated by calling ImGui::EndFrame or ImGui::Render)
     // (in the future we will attempt to organize this feature to remove the need for a "main viewport")
-    ImGuiViewport*                  MainViewport;                           // Guaranteed to be == Viewports[0]
     ImVector<ImGuiViewport*>        Viewports;                              // Main viewports, followed by all secondary viewports.
     ImGuiPlatformIO()               { memset(this, 0, sizeof(*this)); }     // Zero clear
 };
@@ -2940,57 +3022,7 @@ struct ImGuiPlatformMonitor
     ImGuiPlatformMonitor()          { MainPos = MainSize = WorkPos = WorkSize = ImVec2(0, 0); DpiScale = 1.0f; }
 };
 
-// Flags stored in ImGuiViewport::Flags, giving indications to the platform backends.
-enum ImGuiViewportFlags_
-{
-    ImGuiViewportFlags_None                     = 0,
-    ImGuiViewportFlags_NoDecoration             = 1 << 0,   // Platform Window: Disable platform decorations: title bar, borders, etc. (generally set all windows, but if ImGuiConfigFlags_ViewportsDecoration is set we only set this on popups/tooltips)
-    ImGuiViewportFlags_NoTaskBarIcon            = 1 << 1,   // Platform Window: Disable platform task bar icon (generally set on popups/tooltips, or all windows if ImGuiConfigFlags_ViewportsNoTaskBarIcon is set)
-    ImGuiViewportFlags_NoFocusOnAppearing       = 1 << 2,   // Platform Window: Don't take focus when created.
-    ImGuiViewportFlags_NoFocusOnClick           = 1 << 3,   // Platform Window: Don't take focus when clicked on.
-    ImGuiViewportFlags_NoInputs                 = 1 << 4,   // Platform Window: Make mouse pass through so we can drag this window while peaking behind it.
-    ImGuiViewportFlags_NoRendererClear          = 1 << 5,   // Platform Window: Renderer doesn't need to clear the framebuffer ahead (because we will fill it entirely).
-    ImGuiViewportFlags_TopMost                  = 1 << 6,   // Platform Window: Display on top (for tooltips only).
-    ImGuiViewportFlags_Minimized                = 1 << 7,   // Platform Window: Window is minimized, can skip render. When minimized we tend to avoid using the viewport pos/size for clipping window or testing if they are contained in the viewport.
-    ImGuiViewportFlags_NoAutoMerge              = 1 << 8,   // Platform Window: Avoid merging this window into another host window. This can only be set via ImGuiWindowClass viewport flags override (because we need to now ahead if we are going to create a viewport in the first place!).
-    ImGuiViewportFlags_CanHostOtherWindows      = 1 << 9    // Main viewport: can host multiple imgui windows (secondary viewports are associated to a single window).
-};
-
-// The viewports created and managed by Dear ImGui. The role of the platform backend is to create the platform/OS windows corresponding to each viewport.
-// - Main Area = entire viewport.
-// - Work Area = entire viewport minus sections optionally used by menu bars, status bars. Some positioning code will prefer to use this. Window are also trying to stay within this area.
-struct ImGuiViewport
-{
-    ImGuiID             ID;                     // Unique identifier for the viewport
-    ImGuiViewportFlags  Flags;                  // See ImGuiViewportFlags_
-    ImVec2              Pos;                    // Main Area: Position of the viewport (the imgui coordinates are the same as OS desktop/native coordinates)
-    ImVec2              Size;                   // Main Area: Size of the viewport.
-    ImVec2              WorkOffsetMin;          // Work Area: Offset from Pos to top-left corner of Work Area. Generally (0,0) or (0,+main_menu_bar_height). Work Area is Full Area but without menu-bars/status-bars (so WorkArea always fit inside Pos/Size!)
-    ImVec2              WorkOffsetMax;          // Work Area: Offset from Pos+Size to bottom-right corner of Work Area. Generally (0,0) or (0,-status_bar_height).
-    float               DpiScale;               // 1.0f = 96 DPI = No extra scale.
-    ImDrawData*         DrawData;               // The ImDrawData corresponding to this viewport. Valid after Render() and until the next call to NewFrame().
-    ImGuiID             ParentViewportId;       // (Advanced) 0: no parent. Instruct the platform backend to setup a parent/child relationship between platform windows.
-
-    // Our design separate the Renderer and Platform backends to facilitate combining default backends with each others.
-    // When our create your own backend for a custom engine, it is possible that both Renderer and Platform will be handled
-    // by the same system and you may not need to use all the UserData/Handle fields.
-    // The library never uses those fields, they are merely storage to facilitate backend implementation.
-    void*               RendererUserData;       // void* to hold custom data structure for the renderer (e.g. swap chain, framebuffers etc.). generally set by your Renderer_CreateWindow function.
-    void*               PlatformUserData;       // void* to hold custom data structure for the OS / platform (e.g. windowing info, render context). generally set by your Platform_CreateWindow function.
-    void*               PlatformHandle;         // void* for FindViewportByPlatformHandle(). (e.g. suggested to use natural platform handle such as HWND, GLFWWindow*, SDL_Window*)
-    void*               PlatformHandleRaw;      // void* to hold lower-level, platform-native window handle (e.g. the HWND) when using an abstraction layer like GLFW or SDL (where PlatformHandle would be a SDL_Window*)
-    bool                PlatformRequestMove;    // Platform window requested move (e.g. window was moved by the OS / host window manager, authoritative position will be OS window position)
-    bool                PlatformRequestResize;  // Platform window requested resize (e.g. window was resized by the OS / host window manager, authoritative size will be OS window size)
-    bool                PlatformRequestClose;   // Platform window requested closure (e.g. window was moved by the OS / host window manager, e.g. pressing ALT-F4)
-
-    ImGuiViewport()     { ID = 0; Flags = 0; DpiScale = 0.0f; DrawData = NULL; ParentViewportId = 0; RendererUserData = PlatformUserData = PlatformHandle = PlatformHandleRaw = NULL; PlatformRequestMove = PlatformRequestResize = PlatformRequestClose = false; }
-    ~ImGuiViewport()    { IM_ASSERT(PlatformUserData == NULL && RendererUserData == NULL); }
-
-    // Access work-area rectangle with GetWorkXXX functions (see comments above)
-    ImVec2              GetCenter()             { return ImVec2(Pos.x + Size.x * 0.5f, Pos.y + Size.y * 0.5f); }
-    ImVec2              GetWorkPos()            { return ImVec2(Pos.x + WorkOffsetMin.x, Pos.y + WorkOffsetMin.y); }
-    ImVec2              GetWorkSize()           { return ImVec2(Size.x - WorkOffsetMin.x + WorkOffsetMax.x, Size.y - WorkOffsetMin.y + WorkOffsetMax.y); } // This not clamped
-};
+//-----------------------------------------------------------------------------
 
 #if defined(__clang__)
 #pragma clang diagnostic pop