ImFont: Added FindGlyphNoFallback. Fixed MergeMode broken by 1ef1acbd8d

imgui.h

@@ -1784,6 +1784,7 @@ struct 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; }

imgui_demo.cpp

@@ -2222,13 +2222,11 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
                 if (ImGui::TreeNode("Glyphs", "Glyphs (%d)", font->Glyphs.Size))
                 {
                     // Display all glyphs of the fonts in separate pages of 256 characters
-                    const ImFontGlyph* glyph_fallback = font->FallbackGlyph; // Forcefully/dodgily make FindGlyph() return NULL on fallback, which isn't the default behavior.
-                    font->FallbackGlyph = NULL;
                     for (int base = 0; base < 0x10000; base += 256)
                     {
                         int count = 0;
                         for (int n = 0; n < 256; n++)
-                            count += font->FindGlyph((ImWchar)(base + n)) ? 1 : 0;
+                            count += font->FindGlyphNoFallback((ImWchar)(base + n)) ? 1 : 0;
                         if (count > 0 && ImGui::TreeNode((void*)(intptr_t)base, "U+%04X..U+%04X (%d %s)", base, base+255, count, count > 1 ? "glyphs" : "glyph"))
                         {
                             float cell_spacing = style.ItemSpacing.y;
@@ -2239,7 +2237,7 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
                             {
                                 ImVec2 cell_p1(base_pos.x + (n % 16) * (cell_size.x + cell_spacing), base_pos.y + (n / 16) * (cell_size.y + cell_spacing));
                                 ImVec2 cell_p2(cell_p1.x + cell_size.x, cell_p1.y + cell_size.y);
-                                const ImFontGlyph* glyph = font->FindGlyph((ImWchar)(base+n));
+                                const ImFontGlyph* glyph = font->FindGlyphNoFallback((ImWchar)(base+n));
                                 draw_list->AddRect(cell_p1, cell_p2, glyph ? IM_COL32(255,255,255,100) : IM_COL32(255,255,255,50));
                                 font->RenderChar(draw_list, cell_size.x, cell_p1, ImGui::GetColorU32(ImGuiCol_Text), (ImWchar)(base+n)); // We use ImFont::RenderChar as a shortcut because we don't have UTF-8 conversion functions available to generate a string.
                                 if (glyph && ImGui::IsMouseHoveringRect(cell_p1, cell_p2))
@@ -2257,7 +2255,6 @@ void ImGui::ShowStyleEditor(ImGuiStyle* ref)
                             ImGui::TreePop();
                         }
                     }
-                    font->FallbackGlyph = glyph_fallback;
                     ImGui::TreePop();
                 }
                 ImGui::TreePop();

imgui_draw.cpp

@@ -1841,7 +1841,7 @@ bool    ImFontAtlasBuildWithStbTruetype(ImFontAtlas* atlas)
                     continue;
 
                 const int codepoint = range.first_unicode_codepoint_in_range + char_idx;
-                if (cfg.MergeMode && dst_font->FindGlyph((unsigned short)codepoint))
+                if (cfg.MergeMode && dst_font->FindGlyphNoFallback((unsigned short)codepoint))
                     continue;
 
                 stbtt_aligned_quad q;
@@ -2205,8 +2205,7 @@ void ImFont::BuildLookupTable()
         IndexLookup[(int)tab_glyph.Codepoint] = (unsigned short)(Glyphs.Size-1);
     }
 
-    FallbackGlyph = NULL;
+    FallbackGlyph = FindGlyphNoFallback(FallbackChar);
-    FallbackGlyph = FindGlyph(FallbackChar);
     FallbackAdvanceX = FallbackGlyph ? FallbackGlyph->AdvanceX : 0.0f;
     for (int i = 0; i < max_codepoint + 1; i++)
         if (IndexAdvanceX[i] < 0.0f)
@@ -2268,13 +2267,22 @@ void ImFont::AddRemapChar(ImWchar dst, ImWchar src, bool overwrite_dst)
 
 const ImFontGlyph* ImFont::FindGlyph(ImWchar c) const
 {
-    if (c < IndexLookup.Size)
+    if (c >= IndexLookup.Size)
-    {
+        return FallbackGlyph;
-        const unsigned short i = IndexLookup[c];
+    const unsigned short i = IndexLookup[c];
-        if (i != (unsigned short)-1)
+    if (i == (unsigned short)-1)
-            return &Glyphs.Data[i];
+        return FallbackGlyph;
-    }
+    return &Glyphs.Data[i];
-    return FallbackGlyph;
+}
+
+const ImFontGlyph* ImFont::FindGlyphNoFallback(ImWchar c) const
+{
+    if (c >= IndexLookup.Size)
+        return NULL;
+    const unsigned short i = IndexLookup[c];
+    if (i == (unsigned short)-1)
+        return NULL;
+    return &Glyphs.Data[i];
 }
 
 const char* ImFont::CalcWordWrapPositionA(float scale, const char* text, const char* text_end, float wrap_width) const

misc/freetype/imgui_freetype.cpp

@@ -333,7 +333,7 @@ bool ImGuiFreeType::BuildFontAtlas(ImFontAtlas* atlas, unsigned int extra_flags)
         {
             for (uint32_t codepoint = in_range[0]; codepoint <= in_range[1]; ++codepoint) 
             {
-                if (cfg.MergeMode && dst_font->FindGlyph((unsigned short)codepoint))
+                if (cfg.MergeMode && dst_font->FindGlyphNoFallback((unsigned short)codepoint))
                     continue;
 
                 FT_Glyph ft_glyph = NULL;