Font: Moved functions to internal block (not enforced). Made ConfigData pointer const. Added link to stb's notes.

Author: ocornut

imgui.cpp

@@ -805,9 +805,9 @@ CODE
 
       // Options
       ImFontConfig config;
-      config.OversampleH = 3;
+      config.OversampleH = 2;
       config.OversampleV = 1;
-      config.GlyphOffset.y -= 2.0f;      // Move everything by 2 pixels up
+      config.GlyphOffset.y -= 1.0f;      // Move everything by 1 pixels up
       config.GlyphExtraSpacing.x = 1.0f; // Increase spacing between characters
       io.Fonts->AddFontFromFileTTF("myfontfile.ttf", size_pixels, &config);
 

imgui.h

@@ -1914,8 +1914,8 @@ 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. We don't use sub-pixel positions on the Y axis.
-    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. 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. 
     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.
@@ -2080,7 +2080,7 @@ struct ImFontAtlas
 struct ImFont
 {
     // Members: Hot ~24/32 bytes (for CalcTextSize)
-    ImVector<float>             IndexAdvanceX;      // 12/16 // out //            // Sparse. Glyphs->AdvanceX in a directly indexable way (more cache-friendly, for CalcTextSize functions which are often bottleneck in large UI).
+    ImVector<float>             IndexAdvanceX;      // 12/16 // out //            // Sparse. Glyphs->AdvanceX in a directly indexable way (cache-friendly for CalcTextSize functions which only this this info, and are often bottleneck in large UI).
     float                       FontSize;           // 4     // in  // <user set> // Height of characters, set during loading (don't change after loading)
     float                       FallbackAdvanceX;   // 4     // out // = FallbackGlyph->AdvanceX
     ImWchar                     FallbackChar;       // 2     // in  // = '?'      // Replacement glyph if one isn't found. Only set via SetFallbackChar()
@@ -2093,21 +2093,18 @@ struct ImFont
 
     // Members: Cold ~28/40 bytes
     ImFontAtlas*                ContainerAtlas;     // 4-8   // out //            // What we has been loaded into
-    ImFontConfig*               ConfigData;         // 4-8   // in  //            // Pointer within ContainerAtlas->ConfigData
+    const ImFontConfig*         ConfigData;         // 4-8   // in  //            // Pointer within ContainerAtlas->ConfigData
     short                       ConfigDataCount;    // 2     // in  // ~ 1        // Number of ImFontConfig involved in creating this font. Bigger than 1 when merging multiple font sources into one ImFont.
     bool                        DirtyLookupTables;  // 1     // out //
     float                       Scale;              // 4     // in  // = 1.f      // Base font scale, multiplied by the per-window font scale which you can adjust with SetWindowFontScale()
-    float                       Ascent, Descent;    // 8     // out               // Ascent: distance from top to bottom of e.g. 'A' [0..FontSize]
-    int                         MetricsTotalSurface;// 4     // out               // Total surface in pixels to get an idea of the font rasterization/texture cost (not exact, we approximate the cost of padding between glyphs)
+    float                       Ascent, Descent;    // 8     // out //            // Ascent: distance from top to bottom of e.g. 'A' [0..FontSize]
+    int                         MetricsTotalSurface;// 4     // out //            // Total surface in pixels to get an idea of the font rasterization/texture cost (not exact, we approximate the cost of padding between glyphs)
 
     // Methods
     IMGUI_API ImFont();
     IMGUI_API ~ImFont();
-    IMGUI_API void              ClearOutputData();
-    IMGUI_API void              BuildLookupTable();
     IMGUI_API const ImFontGlyph*FindGlyph(ImWchar c) const;
     IMGUI_API const ImFontGlyph*FindGlyphNoFallback(ImWchar c) const;
-    IMGUI_API void              SetFallbackChar(ImWchar c);
     float                       GetCharAdvance(ImWchar c) const     { return ((int)c < IndexAdvanceX.Size) ? IndexAdvanceX[(int)c] : FallbackAdvanceX; }
     bool                        IsLoaded() const                    { return ContainerAtlas != NULL; }
     const char*                 GetDebugName() const                { return ConfigData ? ConfigData->Name : "<unknown>"; }
@@ -2119,10 +2116,13 @@ struct ImFont
     IMGUI_API void              RenderChar(ImDrawList* draw_list, float size, ImVec2 pos, ImU32 col, ImWchar c) const;
     IMGUI_API void              RenderText(ImDrawList* draw_list, float size, ImVec2 pos, ImU32 col, const ImVec4& clip_rect, const char* text_begin, const char* text_end, float wrap_width = 0.0f, bool cpu_fine_clip = false) const;
 
-    // [Internal]
+    // [Internal] Don't use!
+    IMGUI_API void              BuildLookupTable();
+    IMGUI_API void              ClearOutputData();
     IMGUI_API void              GrowIndex(int new_size);
     IMGUI_API void              AddGlyph(ImWchar c, float x0, float y0, float x1, float y1, float u0, float v0, float u1, float v1, float advance_x);
     IMGUI_API void              AddRemapChar(ImWchar dst, ImWchar src, bool overwrite_dst = true); // Makes 'dst' character/glyph points to 'src' character/glyph. Currently needs to be called AFTER fonts have been built.
+    IMGUI_API void              SetFallbackChar(ImWchar c);
 
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
     typedef ImFontGlyph Glyph; // OBSOLETE 1.52+

imgui_demo.cpp

@@ -2913,7 +2913,7 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
                     const float surface_sqrt = sqrtf((float)font->MetricsTotalSurface);
                     ImGui::Text("Texture surface: %d pixels (approx) ~ %dx%d", font->MetricsTotalSurface, (int)surface_sqrt, (int)surface_sqrt);
                     for (int config_i = 0; config_i < font->ConfigDataCount; config_i++)
-                        if (ImFontConfig* cfg = &font->ConfigData[config_i])
+                        if (const ImFontConfig* cfg = &font->ConfigData[config_i])
                             ImGui::BulletText("Input %d: \'%s\', Oversample: (%d,%d), PixelSnapH: %d", config_i, cfg->Name, cfg->OversampleH, cfg->OversampleV, cfg->PixelSnapH);
                     if (ImGui::TreeNode("Glyphs", "Glyphs (%d)", font->Glyphs.Size))
                     {