Fonts: ImFontConfig: added GlyphExcludeRanges[].

imgui.h

@@ -3432,6 +3432,7 @@ struct ImFontConfig
     //ImVec2        GlyphExtraSpacing;      // 0, 0     // (REMOVED AT IT SEEMS LARGELY OBSOLETE. PLEASE REPORT IF YOU WERE USING THIS). Extra spacing (in pixels) between glyphs when rendered: essentially add to glyph->AdvanceX. Only X axis is supported for now.
     ImVec2          GlyphOffset;            // 0, 0     // Offset (in pixels) all glyphs from this font input. Absolute value for default size, other sizes will scale this value.
     const ImWchar*  GlyphRanges;            // NULL     // THE ARRAY DATA NEEDS TO PERSIST AS LONG AS THE FONT IS ALIVE. Pointer to a user-provided list of Unicode range (2 value per range, values are inclusive, zero-terminated list).
+    const ImWchar*  GlyphExcludeRanges;     // NULL     // THE ARRAY DATA NEEDS TO PERSIST AS LONG AS THE FONT IS ALIVE. Pointer to a VERY SHORT user-provided list of Unicode range (2 value per range, values are inclusive, zero-terminated list). This is very close to GlyphRanges[] but designed to exclude ranges from a font source, when merging fonts with overlapping glyphs.
     float           GlyphMinAdvanceX;       // 0        // Minimum AdvanceX for glyphs, set Min to align font icons, set both Min/Max to enforce mono-space font. Absolute value for default size, other sizes will scale this value.
     float           GlyphMaxAdvanceX;       // FLT_MAX  // Maximum AdvanceX for glyphs
     float           GlyphExtraAdvanceX;     // 0        // Extra spacing (in pixels) between glyphs. Please contact us if you are using this.

imgui_draw.cpp

@@ -2990,6 +2990,15 @@ ImFont* ImFontAtlas::AddFont(const ImFontConfig* font_cfg)
         memcpy(new_font_cfg.FontData, font_cfg->FontData, (size_t)new_font_cfg.FontDataSize);
     }
 
+    // Sanity check
+    if (font_cfg->GlyphExcludeRanges != NULL)
+    {
+        int size = 0;
+        for (const ImWchar* p = font_cfg->GlyphExcludeRanges; p[0] != 0; p++, size++) {}
+        IM_ASSERT((size & 1) == 0 && "GlyphExcludeRanges[] size must be multiple of two!");
+        IM_ASSERT((size <= 64) && "GlyphExcludeRanges[] size must be small!");
+    }
+
     // Round font size
     // - We started rounding in 1.90 WIP (18991) as our layout system currently doesn't support non-rounded font size well yet.
     // - Note that using io.FontGlobalScale or SetWindowFontScale(), with are legacy-ish, partially supported features, can still lead to unrounded sizes.
@@ -4149,7 +4158,7 @@ ImFontGlyph* ImFontBaked::BuildLoadGlyph(ImWchar codepoint)
         return NULL;
 
     //char utf8_buf[5];
-    //IMGUI_DEBUG_LOG("[font] BuildAddGlyph U+%04X (%s)\n", (unsigned int)codepoint, ImTextCharToUtf8(utf8_buf, (unsigned int)codepoint));
+    //IMGUI_DEBUG_LOG("[font] BuildLoadGlyph U+%04X (%s)\n", (unsigned int)codepoint, ImTextCharToUtf8(utf8_buf, (unsigned int)codepoint));
 
     // Load from single source or all sources?
     int srcs_count = (font->LockSingleSrcConfigIdx != -1) ? 1 : font->SourcesCount;
@@ -4293,6 +4302,16 @@ static void ImGui_ImplStbTrueType_FontBakedInit(ImFontAtlas* atlas, ImFontBaked*
     }
 }
 
+// Important! This assume by ImFontConfig::GlyphFilter is a SMALL ARRAY (e.g. <10 entries)
+bool ImFontAtlasBuildAcceptCodepointForSource(ImFontConfig* src, ImWchar codepoint)
+{
+    if (const ImWchar* exclude_list = src->GlyphExcludeRanges)
+        for (; exclude_list[0] != 0; exclude_list += 2)
+            if (codepoint >= exclude_list[0] && codepoint <= exclude_list[1])
+                return false;
+    return true;
+}
+
 static bool ImGui_ImplStbTrueType_FontBakedAddGlyph(ImFontAtlas* atlas, ImFontBaked* baked, ImFontConfig* srcs, int srcs_count, ImWchar codepoint)
 {
     // Search for first font which has the glyph
@@ -4302,6 +4321,8 @@ static bool ImGui_ImplStbTrueType_FontBakedAddGlyph(ImFontAtlas* atlas, ImFontBa
     for (int src_n = 0; src_n < srcs_count; src_n++)
     {
         src = &srcs[src_n];
+        if (src->GlyphExcludeRanges && !ImFontAtlasBuildAcceptCodepointForSource(src, codepoint))
+            continue;
         bd_font_data = (ImGui_ImplStbTrueType_FontSrcData*)src->FontLoaderData;
         IM_ASSERT(bd_font_data);
         glyph_index = stbtt_FindGlyphIndex(&bd_font_data->FontInfo, (int)codepoint);

imgui_internal.h

@@ -3773,6 +3773,7 @@ IMGUI_API void              ImFontAtlasBuildDiscardFontBaked(ImFontAtlas* atlas,
 IMGUI_API void              ImFontAtlasBuildDiscardFontBakedGlyph(ImFontAtlas* atlas, ImFont* font, ImFontBaked* baked, ImFontGlyph* glyph);
 IMGUI_API void              ImFontAtlasBuildPreloadAllGlyphRanges(ImFontAtlas* atlas); // Legacy
 IMGUI_API void              ImFontAtlasBuildGetOversampleFactors(ImFontConfig* src, float size, int* out_oversample_h, int* out_oversample_v);
+IMGUI_API bool              ImFontAtlasBuildAcceptCodepointForSource(ImFontConfig* src, ImWchar codepoint);
 
 IMGUI_API ImFontGlyph*      ImFontAtlasBakedAddFontGlyph(ImFontAtlas* atlas, ImFontBaked* baked, ImFontConfig* src, const ImFontGlyph* in_glyph);
 IMGUI_API ImGuiID           ImFontAtlasBakedGetId(ImGuiID font_id, float baked_size);

misc/freetype/imgui_freetype.cpp

@@ -504,6 +504,8 @@ bool ImGui_ImplFreeType_FontBakedAddGlyph(ImFontAtlas* atlas, ImFontBaked* baked
     for (int src_n = 0; src_n < srcs_count; src_n++)
     {
         src = &srcs[src_n];
+        if (src->GlyphExcludeRanges && !ImFontAtlasBuildFilterCodepointForSource(src, codepoint))
+            continue;
         bd_font_data = (ImGui_ImplFreeType_FontSrcData*)src->FontLoaderData;
         glyph_index = FT_Get_Char_Index(bd_font_data->FtFace, codepoint);
         if (glyph_index != 0)