From c38526d14b38eff269032ac2b00a748ee16964c6 Mon Sep 17 00:00:00 2001
From: Anthony Pesch <inolen@gmail.com>
Date: Sun, 1 Oct 2017 23:40:29 -0400
Subject: [PATCH 1/3] Completely clear font when rebuilding atlas.

Previously, IndexLookup was not cleared on each font, causing FindGlyph to return old glyphs when using MergeMode.
---
 imgui_draw.cpp | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/imgui_draw.cpp b/imgui_draw.cpp
index 73647689..b45cc1ff 100644
--- a/imgui_draw.cpp
+++ b/imgui_draw.cpp
@@ -1540,7 +1540,6 @@ bool    ImFontAtlasBuildWithStbTruetype(ImFontAtlas* atlas)
         const float off_x = cfg.GlyphOffset.x;
         const float off_y = cfg.GlyphOffset.y + (float)(int)(dst_font->Ascent + 0.5f);
 
-        dst_font->FallbackGlyph = NULL; // Always clear fallback so FindGlyph can return NULL. It will be set again in BuildLookupTable()
         for (int i = 0; i < tmp.RangesCount; i++)
         {
             stbtt_pack_range& range = tmp.Ranges[i];
@@ -1582,14 +1581,16 @@ void ImFontAtlasBuildSetupFont(ImFontAtlas* atlas, ImFont* font, ImFontConfig* f
 {
     if (!font_config->MergeMode)
     {
-        font->ContainerAtlas = atlas;
-        font->ConfigData = font_config;
-        font->ConfigDataCount = 0;
+        ImVec2 display_offset = font->DisplayOffset;
+
+        font->Clear();
+
         font->FontSize = font_config->SizePixels;
+        font->DisplayOffset = display_offset;
+        font->ConfigData = font_config;
+        font->ContainerAtlas = atlas;
         font->Ascent = ascent;
         font->Descent = descent;
-        font->Glyphs.resize(0);
-        font->MetricsTotalSurface = 0;
     }
     font->ConfigDataCount++;
 }

From fce41d0b5569ceaf9e7901a013efc68980d57662 Mon Sep 17 00:00:00 2001
From: omar <omarcornut@gmail.com>
Date: Sun, 22 Oct 2017 10:21:49 +0200
Subject: [PATCH 2/3] Demo: Fixed Fonts "set as default button" not having
 collading id on collapsed nodes.

---
 imgui_demo.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/imgui_demo.cpp b/imgui_demo.cpp
index 404dcbdb..35ee618b 100644
--- a/imgui_demo.cpp
+++ b/imgui_demo.cpp
@@ -1951,6 +1951,7 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
         for (int i = 0; i < atlas->Fonts.Size; i++)
         {
             ImFont* font = atlas->Fonts[i];
+            ImGui::PushID(font);
             bool font_details_opened = ImGui::TreeNode(font, "Font %d: \'%s\', %.2f px, %d glyphs", i, font->ConfigData ? font->ConfigData[0].Name : "", font->FontSize, font->Glyphs.Size);
             ImGui::SameLine(); if (ImGui::SmallButton("Set as default")) ImGui::GetIO().FontDefault = font;
             if (font_details_opened)
@@ -2011,6 +2012,7 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
                 }
                 ImGui::TreePop();
             }
+            ImGui::PopID();
         }
         static float window_scale = 1.0f;
         ImGui::DragFloat("this window scale", &window_scale, 0.005f, 0.3f, 2.0f, "%.1f");              // scale only this window

From 7f880674e5c3e594ac034215252b7d1455a1579f Mon Sep 17 00:00:00 2001
From: omar <omarcornut@gmail.com>
Date: Sun, 22 Oct 2017 10:24:56 +0200
Subject: [PATCH 3/3] Font: Renamed ImFont::Clear() to
 ImFont::ClearOutputData() for consistency with what ImFontAtlas does.
 DisplayOffset is set by constructor but not reset by ClearOutputData. (#1349)

---
 imgui.h        |  2 +-
 imgui_draw.cpp | 14 +++++---------
 2 files changed, 6 insertions(+), 10 deletions(-)

diff --git a/imgui.h b/imgui.h
index e281b4f1..c865d357 100644
--- a/imgui.h
+++ b/imgui.h
@@ -1500,7 +1500,7 @@ struct ImFont
     // Methods
     IMGUI_API ImFont();
     IMGUI_API ~ImFont();
-    IMGUI_API void              Clear();
+    IMGUI_API void              ClearOutputData();
     IMGUI_API void              BuildLookupTable();
     IMGUI_API const ImFontGlyph*FindGlyph(ImWchar c) const;
     IMGUI_API void              SetFallbackChar(ImWchar c);
diff --git a/imgui_draw.cpp b/imgui_draw.cpp
index 302c338b..c3a5f3d5 100644
--- a/imgui_draw.cpp
+++ b/imgui_draw.cpp
@@ -1618,12 +1618,8 @@ void ImFontAtlasBuildSetupFont(ImFontAtlas* atlas, ImFont* font, ImFontConfig* f
 {
     if (!font_config->MergeMode)
     {
-        ImVec2 display_offset = font->DisplayOffset;
-
-        font->Clear();
-
+        font->ClearOutputData();
         font->FontSize = font_config->SizePixels;
-        font->DisplayOffset = display_offset;
         font->ConfigData = font_config;
         font->ContainerAtlas = atlas;
         font->Ascent = ascent;
@@ -1904,7 +1900,8 @@ ImFont::ImFont()
 {
     Scale = 1.0f;
     FallbackChar = (ImWchar)'?';
-    Clear();
+    DisplayOffset = ImVec2(0.0f, 1.0f);
+    ClearOutputData();
 }
 
 ImFont::~ImFont()
@@ -1917,13 +1914,12 @@ ImFont::~ImFont()
     if (g.Font == this)
         g.Font = NULL;
     */
-    Clear();
+    ClearOutputData();
 }
 
-void    ImFont::Clear()
+void    ImFont::ClearOutputData()
 {
     FontSize = 0.0f;
-    DisplayOffset = ImVec2(0.0f, 1.0f);
     Glyphs.clear();
     IndexAdvanceX.clear();
     IndexLookup.clear();