Fonts: Add U+FFFD ("replacement character") to default asian glyphs ranges. Remove SetFallbackChar() (amend 0ffd99d31). (#4269)

docs/CHANGELOG.txt

@@ -51,6 +51,7 @@ Other Changes:
 - Fonts: Functions with a 'float size_pixels' parameter can accept zero if it is set in ImFontSize::SizePixels.
 - Fonts: Prefer using U+FFFD character for fallback instead of '?', if available. (#4269)
 - Fonts: Use U+FF0E dot character to construct an ellipsis if U+002E '.' is not available. (#4269)
+- Fonts: Add U+FFFD ("replacement character") to default asian glyphs ranges. (#4269)
 - Demo: Fixed requirement in 1.83 to link with imgui_demo.cpp if IMGUI_DISABLE_METRICS_WINDOW is not set. (#4171)
   Normally the right way to disable compiling the demo is to set IMGUI_DISABLE_DEMO_WINDOWS, but we want to avoid
   implying that the file is required.

imgui.h

@@ -2708,9 +2708,9 @@ struct ImFont
     ImFontAtlas*                ContainerAtlas;     // 4-8   // out //            // What we has been loaded into
     const ImFontConfig*         ConfigData;         // 4-8   // in  //            // Pointer within ContainerAtlas->ConfigData
     short                       ConfigDataCount;    // 2     // in  // ~ 1        // Number of ImFontConfig involved in creating this font. Bigger than 1 when merging multiple font sources into one ImFont.
-    ImWchar                     FallbackChar;       // 2     // in  // = '?'      // Replacement character if a glyph isn't found. Only set via SetFallbackChar()
+    ImWchar                     FallbackChar;       // 2     // out // = FFFD/'?' // Character used if a glyph isn't found.
     ImWchar                     EllipsisChar;       // 2     // out // = '...'    // Character used for ellipsis rendering.
-    ImWchar                     DotChar;            // 2     // out // = '.'      // Dot character used for fallback ellipsis rendering.
+    ImWchar                     DotChar;            // 2     // out // = '.'      // Character used for ellipsis rendering (if a single '...' character isn't found)
     bool                        DirtyLookupTables;  // 1     // out //
     float                       Scale;              // 4     // in  // = 1.f      // Base font scale, multiplied by the per-window font scale which you can adjust with SetWindowFontScale()
     float                       Ascent, Descent;    // 4+4   // out //            // Ascent: distance from top to bottom of e.g. 'A' [0..FontSize]
@@ -2740,7 +2740,6 @@ struct ImFont
     IMGUI_API void              AddGlyph(const ImFontConfig* src_cfg, ImWchar c, float x0, float y0, float x1, float y1, float u0, float v0, float u1, float v1, float advance_x);
     IMGUI_API void              AddRemapChar(ImWchar dst, ImWchar src, bool overwrite_dst = true); // Makes 'dst' character/glyph points to 'src' character/glyph. Currently needs to be called AFTER fonts have been built.
     IMGUI_API void              SetGlyphVisible(ImWchar c, bool visible);
-    IMGUI_API void              SetFallbackChar(ImWchar c);
     IMGUI_API bool              IsGlyphRangeUnused(unsigned int c_begin, unsigned int c_last);
 };
 

imgui_draw.cpp

@@ -2815,6 +2815,7 @@ const ImWchar*  ImFontAtlas::GetGlyphRangesKorean()
         0x0020, 0x00FF, // Basic Latin + Latin Supplement
         0x3131, 0x3163, // Korean alphabets
         0xAC00, 0xD7A3, // Korean characters
+        0xFFFD, 0xFFFD, // Invalid
         0,
     };
     return &ranges[0];
@@ -2829,6 +2830,7 @@ const ImWchar*  ImFontAtlas::GetGlyphRangesChineseFull()
         0x3000, 0x30FF, // CJK Symbols and Punctuations, Hiragana, Katakana
         0x31F0, 0x31FF, // Katakana Phonetic Extensions
         0xFF00, 0xFFEF, // Half-width characters
+        0xFFFD, 0xFFFD, // Invalid
         0x4e00, 0x9FAF, // CJK Ideograms
         0,
     };
@@ -2905,7 +2907,8 @@ const ImWchar*  ImFontAtlas::GetGlyphRangesChineseSimplifiedCommon()
         0x2000, 0x206F, // General Punctuation
         0x3000, 0x30FF, // CJK Symbols and Punctuations, Hiragana, Katakana
         0x31F0, 0x31FF, // Katakana Phonetic Extensions
-        0xFF00, 0xFFEF  // Half-width characters
+        0xFF00, 0xFFEF, // Half-width characters
+        0xFFFD, 0xFFFD  // Invalid
     };
     static ImWchar full_ranges[IM_ARRAYSIZE(base_ranges) + IM_ARRAYSIZE(accumulative_offsets_from_0x4E00) * 2 + 1] = { 0 };
     if (!full_ranges[0])
@@ -2994,7 +2997,8 @@ const ImWchar*  ImFontAtlas::GetGlyphRangesJapanese()
         0x0020, 0x00FF, // Basic Latin + Latin Supplement
         0x3000, 0x30FF, // CJK Symbols and Punctuations, Hiragana, Katakana
         0x31F0, 0x31FF, // Katakana Phonetic Extensions
-        0xFF00, 0xFFEF  // Half-width characters
+        0xFF00, 0xFFEF, // Half-width characters
+        0xFFFD, 0xFFFD  // Invalid
     };
     static ImWchar full_ranges[IM_ARRAYSIZE(base_ranges) + IM_ARRAYSIZE(accumulative_offsets_from_0x4E00)*2 + 1] = { 0 };
     if (!full_ranges[0])
@@ -3225,12 +3229,6 @@ void ImFont::SetGlyphVisible(ImWchar c, bool visible)
         glyph->Visible = visible ? 1 : 0;
 }
 
-void ImFont::SetFallbackChar(ImWchar c)
-{
-    FallbackChar = c;
-    BuildLookupTable();
-}
-
 void ImFont::GrowIndex(int new_size)
 {
     IM_ASSERT(IndexAdvanceX.Size == IndexLookup.Size);