Remove IO.FontHeight, cached automatically. Added assertions.

imgui.cpp

@@ -104,8 +104,8 @@
       e.g. "##Foobar" display an empty label and uses "##Foobar" as ID
 
  - if you want to use a different font than the default
-   - create bitmap font data using BMFont. allocate ImGui::GetIO().Font and use ->LoadFromFile()/LoadFromMemory(), set ImGui::GetIO().FontHeight
-   - load your texture yourself. texture *MUST* have white pixel at UV coordinate Imgui::GetIO().FontTexUvForWhite. This is used to draw all solid shapes.
+   - create bitmap font data using BMFont. allocate ImGui::GetIO().Font and use ->LoadFromFile()/LoadFromMemory().
+   - load your texture yourself. texture *MUST* have white pixel at UV coordinate ImGui::GetIO().FontTexUvForWhite. This is used to draw all solid shapes.
 
  - tip: the construct 'if (IMGUI_ONCE_UPON_A_FRAME)' will evaluate to true only once a frame, you can use it to add custom UI in the middle of a deep nested inner loop in your code.
  - tip: you can call Render() multiple times (e.g for VR renders), up to you to communicate the extra state to your RenderDrawListFn function.
@@ -604,6 +604,8 @@ struct ImGuiState
     bool                    Initialized;
     ImGuiIO                 IO;
     ImGuiStyle              Style;
+	float					FontSize;							// == IO.Font->GetFontSize(). Vertical distance between two lines of text, aka == CalcTextSize(" ").y
+
     float                   Time;
     int                     FrameCount;
     int                     FrameCountRendered;
@@ -709,7 +711,7 @@ public:
 
     ImGuiAabb   Aabb() const                            { return ImGuiAabb(Pos, Pos+Size); }
     ImFont      Font() const                            { return GImGui.IO.Font; }
-    float       FontSize() const                        { return GImGui.IO.FontHeight * FontScale; }
+    float       FontSize() const                        { return GImGui.FontSize * FontScale; }
     ImVec2      CursorPos() const                       { return DC.CursorPos; }
     float       TitleBarHeight() const                  { return (Flags & ImGuiWindowFlags_NoTitleBar) ? 0 : FontSize() + GImGui.Style.FramePadding.y * 2.0f; }
     ImGuiAabb   TitleBarAabb() const                    { return ImGuiAabb(Pos, Pos + ImVec2(SizeFull.x, TitleBarHeight())); }
@@ -1197,14 +1199,15 @@ void NewFrame()
             ImGui::GetDefaultFontData(&fnt_data, &fnt_size, NULL, NULL);
             g.IO.Font = new ImBitmapFont();
             g.IO.Font->LoadFromMemory(fnt_data, fnt_size);
-            g.IO.FontHeight = g.IO.Font->GetFontSize();
         }
         g.Initialized = true;
     }
+	IM_ASSERT(g.IO.Font && g.IO.Font->IsLoaded());  // Font not loaded
 
     g.Time += g.IO.DeltaTime;
     g.FrameCount += 1;
     g.Tooltip[0] = '\0';
+    g.FontSize = g.IO.Font->GetFontSize();
 
     // Update inputs state
     if (g.IO.MousePos.x < 0 && g.IO.MousePos.y < 0)

imgui.h

@@ -391,7 +391,6 @@ struct ImGuiIO
     float       MouseDoubleClickMaxDist;    // = 6.0f                   // Distance threshold to stay in to validate a double-click, in pixels.
     int         KeyMap[ImGuiKey_COUNT];     // <unset>                  // Map of indices into the KeysDown[512] entries array
     ImFont      Font;                       // <auto>                   // Gets passed to text functions. Typedef ImFont to the type you want (ImBitmapFont* or your own font).
-    float       FontHeight;                 // <auto>                   // Default font height, must be the vertical distance between two lines of text, aka == CalcTextSize(" ").y
     ImVec2      FontTexUvForWhite;          // = (0.0f,0.0f)            // Font texture must have a white pixel at this UV coordinate. Adjust if you are using custom texture.
     bool        FontAllowScaling;           // = false                  // Set to allow scaling text with CTRL+Wheel.
     float       PixelCenterOffset;          // = 0.0f                   // Try to set to 0.5f or 0.375f if rendering is blurry
@@ -642,6 +641,7 @@ struct ImBitmapFont
     void                    BuildLookupTable();
     const FntGlyph *        FindGlyph(unsigned short c) const;
     float                   GetFontSize() const { return (float)Info->FontSize; }
+	bool					IsLoaded() const { return Info != NULL && Common != NULL && Glyphs != NULL; }
 
     ImVec2                  CalcTextSize(float size, float max_width, const char* text_begin, const char* text_end, const char** remaining = NULL) const;
     void                    RenderText(float size, ImVec2 pos, ImU32 col, const ImVec4& clip_rect, const char* text_begin, const char* text_end, ImDrawVert*& out_vertices) const;