From 23dc46c4f8bf6aaf83d70f54441916404bf1aba5 Mon Sep 17 00:00:00 2001
From: ocornut <omar@miracleworld.net>
Date: Mon, 31 Mar 2025 19:24:59 +0200
Subject: [PATCH] Fonts: added RemoveCustomRect().

+ internally add ImFontAtlasPackReuseRectEntry()
---
 imgui.h          |  1 +
 imgui_draw.cpp   | 29 +++++++++++++++++++----------
 imgui_internal.h |  4 ++--
 3 files changed, 22 insertions(+), 12 deletions(-)

diff --git a/imgui.h b/imgui.h
index ce5decfa4..a3d70bb98 100644
--- a/imgui.h
+++ b/imgui.h
@@ -3634,6 +3634,7 @@ struct ImFontAtlas
     //   - AddCustomRectFontGlyph() --> Prefer using custom ImFontLoader inside ImFontConfig
     //   - ImFontAtlasCustomRect    --> Renamed to ImFontAtlasRect
     IMGUI_API ImFontAtlasRectId AddCustomRect(int width, int height);                               // Register a rectangle. Return -1 (ImFontAtlasRectId_Invalid) on error.
+    IMGUI_API void              RemoveCustomRect(ImFontAtlasRectId id);                             // Unregister a rectangle. Existing pixels will stay in texture until resized / garbage collected.
     IMGUI_API bool              GetCustomRect(ImFontAtlasRectId id, ImFontAtlasRect* out_r) const;  // Get rectangle coordinates for current texture. Valid immediately, never store this (read above)!
 
     //-------------------------------------------
diff --git a/imgui_draw.cpp b/imgui_draw.cpp
index 83db3576b..7cc1351fb 100644
--- a/imgui_draw.cpp
+++ b/imgui_draw.cpp
@@ -2499,8 +2499,10 @@ void ImTextureData::DestroyPixels()
 // - ImFontAtlasBuildNotifySetFont()
 //-----------------------------------------------------------------------------
 // - ImFontAtlas::AddCustomRect()
-// - ImFontAtlas::AddCustomRectFontGlyph()
+// - ImFontAtlas::RemoveCustomRect()
 // - ImFontAtlas::GetCustomRect()
+// - ImFontAtlas::AddCustomRectFontGlyph() [legacy]
+// - ImFontAtlas::AddCustomRectFontGlyphForSize() [legacy]
 // - ImFontAtlasGetMouseCursorTexData()
 //-----------------------------------------------------------------------------
 // - ImFontAtlasBuildMain()
@@ -2538,6 +2540,7 @@ void ImTextureData::DestroyPixels()
 //-----------------------------------------------------------------------------
 // - ImFontAtlasPackInit()
 // - ImFontAtlasPackAllocRectEntry()
+// - ImFontAtlasPackReuseRectEntry()
 // - ImFontAtlasPackDiscardRect()
 // - ImFontAtlasPackAddRect()
 // - ImFontAtlasPackGetRect()
@@ -3239,6 +3242,12 @@ ImFontAtlasRectId ImFontAtlas::AddCustomRect(int width, int height)
     return r_id;
 }
 
+void ImFontAtlas::RemoveCustomRect(ImFontAtlasRectId id)
+{
+    IM_ASSERT(id != ImFontAtlasRectId_Invalid);
+    ImFontAtlasPackDiscardRect(this, id);
+}
+
 #ifndef IMGUI_DISABLE_OBSOLETE_FUNCTIONS
 // This API does not make sense anymore with scalable fonts.
 // - Prefer adding a font source (ImFontConfig) using a custom/procedural loader.
@@ -4095,7 +4104,7 @@ ImVec2i ImFontAtlasBuildGetTextureSizeEstimate(ImFontAtlas* atlas)
     return ImVec2i(new_tex_w, new_tex_h);
 }
 
-// Clear all output. Invalidates all AddCustomRectXXX return values.
+// Clear all output. Invalidates all AddCustomRect() return values!
 void ImFontAtlasBuildClear(ImFontAtlas* atlas)
 {
     ImVec2i new_tex_size = ImFontAtlasBuildGetTextureSizeEstimate(atlas);
@@ -4237,6 +4246,13 @@ static ImFontAtlasRectId ImFontAtlasPackAllocRectEntry(ImFontAtlas* atlas, int r
     return (ImFontAtlasRectId)index_idx;
 }
 
+static ImFontAtlasRectId ImFontAtlasPackReuseRectEntry(ImFontAtlas* atlas, ImFontAtlasRectEntry* overwrite_entry)
+{
+    IM_ASSERT(overwrite_entry->Used);
+    overwrite_entry->TargetIndex = atlas->Builder->Rects.Size - 1;
+    return atlas->Builder->RectsIndex.index_from_ptr(overwrite_entry);
+}
+
 // This is expected to be called in batches and followed by a repack
 void ImFontAtlasPackDiscardRect(ImFontAtlas* atlas, ImFontAtlasRectId id)
 {
@@ -4300,16 +4316,9 @@ ImFontAtlasRectId ImFontAtlasPackAddRect(ImFontAtlas* atlas, int w, int h, ImFon
 
     builder->Rects.push_back(r);
     if (overwrite_entry != NULL)
-    {
-        // Write into an existing entry instead of adding one (used during repack)
-        IM_ASSERT(overwrite_entry->Used);
-        overwrite_entry->TargetIndex = builder->Rects.Size - 1;
-        return builder->RectsIndex.index_from_ptr(overwrite_entry);
-    }
+        return ImFontAtlasPackReuseRectEntry(atlas, overwrite_entry); // Write into an existing entry instead of adding one (used during repack)
     else
-    {
         return ImFontAtlasPackAllocRectEntry(atlas, builder->Rects.Size - 1);
-    }
 }
 
 // Important: don'return pointer valid until next call to AddRect(), e.g. FindGlyph(), CalcTextSize() can all potentially invalidate previous pointers.
diff --git a/imgui_internal.h b/imgui_internal.h
index 7389c0216..0a9961a45 100644
--- a/imgui_internal.h
+++ b/imgui_internal.h
@@ -3701,8 +3701,8 @@ IMGUI_API const ImFontLoader* ImFontAtlasGetFontLoaderForStbTruetype();
 // Having this also makes it easier to e.g. sort rectangles during repack.
 struct ImFontAtlasRectEntry
 {
-    int             TargetIndex : 31; // When Used: ImFontAtlasRectId -> into Rects[]. When unused: index to next unused RectsIndex[] slot to consume free-list.
-    unsigned int    Used : 1;
+    int                 TargetIndex : 31;   // When Used: ImFontAtlasRectId -> into Rects[]. When unused: index to next unused RectsIndex[] slot to consume free-list.
+    unsigned int        Used : 1;
 };
 
 // Data available to potential texture post-processing functions