Fonts: added "Input Glyphs Overlap Detection Tool". Added "Clear bakes", "Clear unused" buttons. Move code.

imgui.cpp

@@ -16699,6 +16699,21 @@ void ImGui::DebugNodeDrawCmdShowMeshAndBoundingBox(ImDrawList* out_draw_list, co
     out_draw_list->Flags = backup_flags;
 }
 
+// [DEBUG] Compute mask of inputs with the same codepoint.
+static int CalcFontGlyphSrcOverlapMask(ImFontAtlas* atlas, ImFont* font, unsigned int codepoint)
+{
+    int mask = 0, count = 0;
+    for (int src_n = 0; src_n < font->Sources.Size; src_n++)
+    {
+        ImFontConfig* src = font->Sources[src_n];
+        if (!(src->FontLoader ? src->FontLoader : atlas->FontLoader)->FontSrcContainsGlyph(atlas, src, (ImWchar)codepoint))
+            continue;
+        mask |= (1 << src_n);
+        count++;
+    }
+    return count > 1 ? mask : 0;
+}
+
 // [DEBUG] Display details for a single font, called by ShowStyleEditor().
 void ImGui::DebugNodeFont(ImFont* font)
 {
@@ -16730,6 +16745,12 @@ void ImGui::DebugNodeFont(ImFont* font)
     if (SmallButton("Remove"))
         atlas->RemoveFont(font);
     EndDisabled();
+    SameLine();
+    if (SmallButton("Clear bakes"))
+        ImFontAtlasFontDiscardBakes(atlas, font, 0);
+    SameLine();
+    if (SmallButton("Clear unused"))
+        ImFontAtlasFontDiscardBakes(atlas, font, 2);
 
     // Display details
     SetNextItemWidth(GetFontSize() * 8);
@@ -16769,6 +16790,37 @@ void ImGui::DebugNodeFont(ImFont* font)
             TreePop();
         }
     }
+    if (font->Sources.Size > 1 && TreeNode("Input Glyphs Overlap Detection Tool"))
+    {
+        TextWrapped("- First Input that contains the glyph is used.\n- Use ImFontConfig::GlyphExcludeRanges[] to specify ranges to ignore glyph in given Input.\n- This tool doesn't cache results and is slow, don't keep it open!");
+        if (BeginTable("table", 2))
+        {
+            for (unsigned int c = 0; c < 0x10000; c++)
+                if (int overlap_mask = CalcFontGlyphSrcOverlapMask(atlas, font, c))
+                {
+                    unsigned int c_end = c + 1;
+                    while (c_end < 0x10000 && CalcFontGlyphSrcOverlapMask(atlas, font, c_end) == overlap_mask)
+                        c_end++;
+                    if (TableNextColumn() && TreeNode((void*)(intptr_t)c, "U+%04X-U+%04X: %d codepoints in %d inputs", c, c_end - 1, c_end - c, ImCountSetBits(overlap_mask)))
+                    {
+                        char utf8_buf[5];
+                        for (unsigned int n = c; n < c_end; n++)
+                            BulletText("Codepoint U+%04X (%s)", n, ImTextCharToUtf8(utf8_buf, n));
+                        TreePop();
+                    }
+                    TableNextColumn();
+                    for (int src_n = 0; src_n < font->Sources.Size; src_n++)
+                        if (overlap_mask & (1 << src_n))
+                        {
+                            Text("%d ", src_n);
+                            SameLine();
+                        }
+                    c = c_end - 1;
+                }
+            EndTable();
+        }
+        TreePop();
+    }
 
     // Display all glyphs of the fonts in separate pages of 256 characters
     for (int baked_n = 0; baked_n < atlas->Builder->BakedPool.Size; baked_n++)

imgui.h

@@ -3456,7 +3456,7 @@ 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     // 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.
+    const ImWchar*  GlyphExcludeRanges;     // NULL     // 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. Use "Input Glyphs Overlap Detection Tool" to find about your overlapping ranges.
     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

@@ -3843,13 +3843,17 @@ void ImFontAtlasBakedDiscard(ImFontAtlas* atlas, ImFont* font, ImFontBaked* bake
     font->LastBaked = NULL;
 }
 
-void ImFontAtlasFontDiscardOutputBakes(ImFontAtlas* atlas, ImFont* font)
+// use unused_frames==0 to discard everything.
+void ImFontAtlasFontDiscardBakes(ImFontAtlas* atlas, ImFont* font, int unused_frames)
 {
     if (ImFontAtlasBuilder* builder = atlas->Builder) // This can be called from font destructor
         for (int baked_n = 0; baked_n < builder->BakedPool.Size; baked_n++)
         {
             ImFontBaked* baked = &builder->BakedPool[baked_n];
-            if (baked->ContainerFont == font && !baked->WantDestroy)
+            if (baked->LastUsedFrame + unused_frames > atlas->Builder->FrameCount)
+                continue;
+            if (baked->ContainerFont != font || baked->WantDestroy)
+                continue;
             ImFontAtlasBakedDiscard(atlas, font, baked);
         }
 }
@@ -4364,7 +4368,8 @@ ImTextureRect* ImFontAtlasPackGetRectSafe(ImFontAtlas* atlas, ImFontAtlasRectId
     return &builder->Rects[index_entry->TargetIndex];
 }
 
-// Important! This assume by ImFontConfig::GlyphFilter is a SMALL ARRAY (e.g. <10 entries)
+// Important! This assume by ImFontConfig::GlyphExcludeRanges[] is a SMALL ARRAY (e.g. <10 entries)
+// Use "Input Glyphs Overlap Detection Tool" to display a list of glyphs provided by multiple sources in order to set this array up.
 static bool ImFontAtlasBuildAcceptCodepointForSource(ImFontConfig* src, ImWchar codepoint)
 {
     if (const ImWchar* exclude_list = src->GlyphExcludeRanges)
@@ -5024,7 +5029,7 @@ ImFont::~ImFont()
 void ImFont::ClearOutputData()
 {
     if (ImFontAtlas* atlas = ContainerAtlas)
-        ImFontAtlasFontDiscardOutputBakes(atlas, this);
+        ImFontAtlasFontDiscardBakes(atlas, this, 0);
     FallbackChar = EllipsisChar = 0;
     memset(Used8kPagesMap, 0, sizeof(Used8kPagesMap));
     LastBaked = NULL;

imgui_internal.h

@@ -3815,7 +3815,7 @@ IMGUI_API void              ImFontAtlasFontSourceAddToFont(ImFontAtlas* atlas, I
 IMGUI_API void              ImFontAtlasFontDestroySourceData(ImFontAtlas* atlas, ImFontConfig* src);
 IMGUI_API bool              ImFontAtlasFontInitOutput(ImFontAtlas* atlas, ImFont* font); // Using FontDestroyOutput/FontInitOutput sequence useful notably if font loader params have changed
 IMGUI_API void              ImFontAtlasFontDestroyOutput(ImFontAtlas* atlas, ImFont* font);
-IMGUI_API void              ImFontAtlasFontDiscardOutputBakes(ImFontAtlas* atlas, ImFont* font);
+IMGUI_API void              ImFontAtlasFontDiscardBakes(ImFontAtlas* atlas, ImFont* font, int unused_frames);
 
 IMGUI_API ImGuiID           ImFontAtlasBakedGetId(ImGuiID font_id, float baked_size, float rasterizer_density);
 IMGUI_API ImFontBaked*      ImFontAtlasBakedGetOrAdd(ImFontAtlas* atlas, ImFont* font, float font_size, float font_rasterizer_density);