BLF: Fallback Font Stack

Allow use of multiple fonts acting together like a fallback stack,
where if a glyph is not found in one it can be retrieved from another.

See D12622 for much more detail

Differential Revision: https://developer.blender.org/D12622

Reviewed by Brecht Van Lommel

10 files changed, 503 insertions, 40 deletions

diff --git a/source/blender/blenfont/BLF_api.h b/source/blender/blenfont/BLF_api.h
index e5e2b1711b1..78c8612f7f5 100644
--- a/source/blender/blenfont/BLF_api.h
+++ b/source/blender/blenfont/BLF_api.h
@@ -14,6 +14,15 @@
 extern "C" {
 #endif
 
+/* Name of subfolder inside BLENDER_DATAFILES that contains font files. */
+#define BLF_DATAFILES_FONTS_DIR "fonts"
+
+/* File name of the default variable-width font. */
+#define BLF_DEFAULT_PROPORTIONAL_FONT "droidsans.ttf"
+
+/* File name of the default fixed-pitch font. */
+#define BLF_DEFAULT_MONOSPACED_FONT "bmonofont-i18n.ttf"
+
 /* enable this only if needed (unused circa 2016) */
 #define BLF_BLUR_ENABLE 0
 
@@ -37,12 +46,14 @@ void BLF_cache_flush_set_fn(void (*cache_flush_fn)(void));
  */
 int BLF_load(const char *name) ATTR_NONNULL();
 int BLF_load_mem(const char *name, const unsigned char *mem, int mem_size) ATTR_NONNULL();
+bool BLF_is_loaded(const char *name) ATTR_NONNULL();
 
 int BLF_load_unique(const char *name) ATTR_NONNULL();
 int BLF_load_mem_unique(const char *name, const unsigned char *mem, int mem_size) ATTR_NONNULL();
 
 void BLF_unload(const char *name) ATTR_NONNULL();
 void BLF_unload_id(int fontid);
+void BLF_unload_all(void);
 
 char *BLF_display_name_from_file(const char *filepath);
 
@@ -312,6 +323,7 @@ int BLF_set_default(void);
 
 int BLF_load_default(bool unique);
 int BLF_load_mono_default(bool unique);
+void BLF_load_font_stack(void);
 
 #ifdef DEBUG
 void BLF_state_print(int fontid);
@@ -331,6 +343,9 @@ void BLF_state_print(int fontid);
 #define BLF_HINTING_FULL (1 << 10)
 #define BLF_BOLD (1 << 11)
 #define BLF_ITALIC (1 << 12)
+#define BLF_MONOSPACED (1 << 13) /* Intended USE is monospaced, regardless of font type. */
+#define BLF_DEFAULT (1 << 14) /* A font within the default stack of fonts. */
+#define BLF_LAST_RESORT (1 << 15) /* Must only be used as last font in the stack. */
 
 #define BLF_DRAW_STR_DUMMY_MAX 1024
 
diff --git a/source/blender/blenfont/intern/blf.c b/source/blender/blenfont/intern/blf.c
index a944ab332bd..a1fcc17ca3f 100644
--- a/source/blender/blenfont/intern/blf.c
+++ b/source/blender/blenfont/intern/blf.c
@@ -34,13 +34,6 @@
 #include "blf_internal.h"
 #include "blf_internal_types.h"
 
-/* Max number of font in memory.
- * Take care that now every font have a glyph cache per size/dpi,
- * so we don't need load the same font with different size, just
- * load one and call BLF_size.
- */
-#define BLF_MAX_FONT 16
-
 #define BLF_RESULT_CHECK_INIT(r_info) \
   if (r_info) { \
     memset(r_info, 0, sizeof(*(r_info))); \
@@ -48,7 +41,7 @@
   ((void)0)
 
 /* Font array. */
-static FontBLF *global_font[BLF_MAX_FONT] = {NULL};
+FontBLF *global_font[BLF_MAX_FONT] = {NULL};
 
 /* XXX: should these be made into global_font_'s too? */
 
@@ -134,6 +127,11 @@ bool BLF_has_glyph(int fontid, unsigned int unicode)
   return false;
 }
 
+bool BLF_is_loaded(const char *name)
+{
+  return blf_search(name) >= 0;
+}
+
 int BLF_load(const char *name)
 {
   /* check if we already load this font. */
@@ -255,6 +253,20 @@ void BLF_unload_id(int fontid)
   }
 }
 
+void BLF_unload_all(void)
+{
+  for (int i = 0; i < BLF_MAX_FONT; i++) {
+    FontBLF *font = global_font[i];
+    if (font) {
+      blf_font_free(font);
+      global_font[i] = NULL;
+    }
+  }
+  blf_mono_font = -1;
+  blf_mono_font_render = -1;
+  BLF_default_set(-1);
+}
+
 void BLF_enable(int fontid, int option)
 {
   FontBLF *font = blf_get(fontid);
diff --git a/source/blender/blenfont/intern/blf_font.c b/source/blender/blenfont/intern/blf_font.c
index a170f27d247..26a72fcb95a 100644
--- a/source/blender/blenfont/intern/blf_font.c
+++ b/source/blender/blenfont/intern/blf_font.c
@@ -18,6 +18,7 @@
 
 #include FT_FREETYPE_H
 #include FT_GLYPH_H
+#include FT_TRUETYPE_TABLES_H /* For TT_OS2 */
 
 #include "MEM_guardedalloc.h"
 
@@ -1288,6 +1289,25 @@ FontBLF *blf_font_new(const char *name, const char *filepath)
   font->filepath = BLI_strdup(filepath);
   blf_font_fill(font);
 
+    /* Save TrueType table with bits to quickly test most unicode block coverage. */
+  TT_OS2 *os2_table = (TT_OS2 *)FT_Get_Sfnt_Table(font->face, FT_SFNT_OS2);
+  if (os2_table) {
+    font->UnicodeRanges[0] = (uint)os2_table->ulUnicodeRange1;
+    font->UnicodeRanges[1] = (uint)os2_table->ulUnicodeRange2;
+    font->UnicodeRanges[2] = (uint)os2_table->ulUnicodeRange3;
+    font->UnicodeRanges[3] = (uint)os2_table->ulUnicodeRange4;
+  }
+
+  /* Detect "Last resort" fonts. They have everything. Usually except last 5 bits.  */
+  if (font->UnicodeRanges[0] == 0xffffffffU && font->UnicodeRanges[1] == 0xffffffffU &&
+      font->UnicodeRanges[2] == 0xffffffffU && font->UnicodeRanges[3] >= 0x7FFFFFFU) {
+    font->flags |= BLF_LAST_RESORT;
+  }
+
+  if (FT_IS_FIXED_WIDTH(font->face)) {
+    font->flags |= BLF_MONOSPACED;
+  }
+
   if (FT_HAS_KERNING(font->face)) {
     /* Create kerning cache table and fill with value indicating "unset". */
     font->kerning_cache = MEM_mallocN(sizeof(KerningCacheBLF), __func__);
diff --git a/source/blender/blenfont/intern/blf_font_default.c b/source/blender/blenfont/intern/blf_font_default.c
index 3a68423e64e..1bde25b5776 100644
--- a/source/blender/blenfont/intern/blf_font_default.c
+++ b/source/blender/blenfont/intern/blf_font_default.c
@@ -11,13 +11,14 @@
 
 #include "BLF_api.h"
 
+#include "BLI_fileops.h"
 #include "BLI_path_util.h"
 
 #include "BKE_appdir.h"
 
 static int blf_load_font_default(const char *filename, const bool unique)
 {
-  const char *dir = BKE_appdir_folder_id(BLENDER_DATAFILES, "fonts");
+  const char *dir = BKE_appdir_folder_id(BLENDER_DATAFILES, BLF_DATAFILES_FONTS_DIR);
   if (dir == NULL) {
     fprintf(stderr,
             "%s: 'fonts' data path not found for '%s', will not be able to display text\n",
@@ -34,10 +35,46 @@ static int blf_load_font_default(const char *filename, const bool unique)
 
 int BLF_load_default(const bool unique)
 {
-  return blf_load_font_default("droidsans.ttf", unique);
+  int font_id = blf_load_font_default(BLF_DEFAULT_PROPORTIONAL_FONT, unique);
+  BLF_enable(font_id, BLF_DEFAULT);
+  return font_id;
 }
 
 int BLF_load_mono_default(const bool unique)
 {
-  return blf_load_font_default("bmonofont-i18n.ttf", unique);
+  int font_id = blf_load_font_default(BLF_DEFAULT_MONOSPACED_FONT, unique);
+  BLF_enable(font_id, BLF_MONOSPACED | BLF_DEFAULT);
+  return font_id;
+}
+
+void BLF_load_font_stack()
+{
+  /* Load these if not already, might have been replaced by user custom. */
+  BLF_load_default(false);
+  BLF_load_mono_default(false);
+
+  const char *path = BKE_appdir_folder_id(BLENDER_DATAFILES, BLF_DATAFILES_FONTS_DIR SEP_STR);
+  if (path && BLI_exists(path)) {
+    struct direntry *dir;
+    uint num_files = BLI_filelist_dir_contents(path, &dir);
+    for (int f = 0; f < num_files; f++) {
+      if (!FILENAME_IS_CURRPAR(dir[f].relname) && !BLI_is_dir(dir[f].path)) {
+        if (!BLF_is_loaded(dir[f].path)) {
+          int font_id = BLF_load(dir[f].path);
+          if (font_id == -1) {
+            fprintf(stderr, "Unable to load font: %s\n", dir[f].path);
+          }
+          else {
+            BLF_enable(font_id, BLF_DEFAULT);
+            /* TODO: FontBLF will later load FT_Face on demand.  When this is in
+             * place we can drop this face now since we have all needed data. */
+          }
+        }
+      }
+    }
+    BLI_filelist_free(dir, num_files);
+  }
+  else {
+    fprintf(stderr, "Fonts not found at %s\n", path);
+  }
 }
diff --git a/source/blender/blenfont/intern/blf_glyph.c b/source/blender/blenfont/intern/blf_glyph.c
index 2694b179a11..32d4be3be0c 100644
--- a/source/blender/blenfont/intern/blf_glyph.c
+++ b/source/blender/blenfont/intern/blf_glyph.c
@@ -39,6 +39,7 @@
 
 #include "BLI_math_vector.h"
 #include "BLI_strict_flags.h"
+#include "BLI_string_utf8.h"
 
 /* -------------------------------------------------------------------- */
 /** \name Internal Utilities
@@ -222,6 +223,335 @@ static GlyphBLF *blf_glyph_cache_add_glyph(
   return g;
 }
 
+/* This table can be used to find a coverage bit based on a charcode. later we can get default
+ * language and script from codepoint.  */
+
+typedef struct eUnicodeBlock {
+  unsigned int first;
+  unsigned int last;
+  int coverage_bit; /* 0-122. -1 is N/A. */
+  /* Later we add primary script and language for Harfbuzz, data from
+   * https://en.wikipedia.org/wiki/Unicode_block */
+} eUnicodeBlock;
+
+static eUnicodeBlock unicode_blocks[] = {
+    /* Must be in ascending order by start of range. */
+    {0x0, 0x7F, 0},           /* Basic Latin. */
+    {0x80, 0xFF, 1},          /* Latin-1 Supplement. */
+    {0x100, 0x17F, 2},        /* Latin Extended-A. */
+    {0x180, 0x24F, 3},        /* Latin Extended-B. */
+    {0x250, 0x2AF, 4},        /* IPA Extensions. */
+    {0x2B0, 0x2FF, 5},        /* Spacing Modifier Letters. */
+    {0x300, 0x36F, 6},        /* Combining Diacritical Marks. */
+    {0x370, 0x3FF, 7},        /* Greek. */
+    {0x400, 0x52F, 9},        /* Cyrillic. */
+    {0x530, 0x58F, 10},       /* Armenian. */
+    {0x590, 0x5FF, 11},       /* Hebrew. */
+    {0x600, 0x6FF, 13},       /* Arabic. */
+    {0x700, 0x74F, 71},       /* Syriac. */
+    {0x750, 0x77F, 13},       /* Arabic Supplement. */
+    {0x780, 0x7BF, 72},       /* Thaana. */
+    {0x7C0, 0x7FF, 14},       /* NKo. */
+    {0x800, 0x83F, -1},       /* Samaritan. */
+    {0x840, 0x85F, -1},       /* Mandaic. */
+    {0x900, 0x97F, 15},       /* Devanagari. */
+    {0x980, 0x9FF, 16},       /* Bengali. */
+    {0xA00, 0xA7F, 17},       /* Gurmukhi. */
+    {0xA80, 0xAFF, 18},       /* Gujarati. */
+    {0xB00, 0xB7F, 19},       /* Oriya. */
+    {0xB80, 0xBFF, 20},       /* Tamil. */
+    {0xC00, 0xC7F, 21},       /* Telugu. */
+    {0xC80, 0xCFF, 22},       /* Kannada. */
+    {0xD00, 0xD7F, 23},       /* Malayalam. */
+    {0xD80, 0xDFF, 73},       /* Sinhala. */
+    {0xE00, 0xE7F, 24},       /* Thai. */
+    {0xE80, 0xEFF, 25},       /* Lao. */
+    {0xF00, 0xFFF, 70},       /* Tibetan. */
+    {0x1000, 0x109F, 74},     /* Myanmar. */
+    {0x10A0, 0x10FF, 26},     /* Georgian. */
+    {0x1100, 0x11FF, 28},     /* Hangul Jamo. */
+    {0x1200, 0x139F, 75},     /* Ethiopic. */
+    {0x13A0, 0x13FF, 76},     /* Cherokee. */
+    {0x1400, 0x167F, 77},     /* Canadian Aboriginal. */
+    {0x1680, 0x169F, 78},     /* Ogham. */
+    {0x16A0, 0x16FF, 79},     /* unic. */
+    {0x1700, 0x171F, 84},     /* Tagalog. */
+    {0x1720, 0x173F, 84},     /* Hanunoo. */
+    {0x1740, 0x175F, 84},     /* Buhid. */
+    {0x1760, 0x177F, 84},     /* Tagbanwa. */
+    {0x1780, 0x17FF, 80},     /* Khmer. */
+    {0x1800, 0x18AF, 81},     /* Mongolian. */
+    {0x1900, 0x194F, 93},     /* Limbu. */
+    {0x1950, 0x197F, 94},     /* Tai Le. */
+    {0x1980, 0x19DF, 95},     /* New Tai Lue". */
+    {0x19E0, 0x19FF, 80},     /* Khmer. */
+    {0x1A00, 0x1A1F, 96},     /* Buginese. */
+    {0x1A20, 0x1AAF, -1},     /* Tai Tham. */
+    {0x1B00, 0x1B7F, 27},     /* Balinese. */
+    {0x1B80, 0x1BBF, 112},    /* Sundanese. */
+    {0x1BC0, 0x1BFF, -1},     /* Batak. */
+    {0x1C00, 0x1C4F, 113},    /* Lepcha. */
+    {0x1C50, 0x1C7F, 114},    /* Ol Chiki. */
+    {0x1D00, 0x1DBF, 4},      /* IPA Extensions. */
+    {0x1DC0, 0x1DFF, 6},      /* Combining Diacritical Marks. */
+    {0x1E00, 0x1EFF, 29},     /* Latin Extended Additional. */
+    {0x1F00, 0x1FFF, 30},     /* Greek Extended. */
+    {0x2000, 0x206F, 31},     /* General Punctuation. */
+    {0x2070, 0x209F, 32},     /* Superscripts And Subscripts. */
+    {0x20A0, 0x20CF, 33},     /* Currency Symbols. */
+    {0x20D0, 0x20FF, 34},     /* Combining Diacritical Marks For Symbols. */
+    {0x2100, 0x214F, 35},     /* Letterlike Symbols. */
+    {0x2150, 0x218F, 36},     /* Number Forms. */
+    {0x2190, 0x21FF, 37},     /* Arrows. */
+    {0x2200, 0x22FF, 38},     /* Mathematical Operators. */
+    {0x2300, 0x23FF, 39},     /* Miscellaneous Technical. */
+    {0x2400, 0x243F, 40},     /* Control Pictures. */
+    {0x2440, 0x245F, 41},     /* Optical Character Recognition. */
+    {0x2460, 0x24FF, 42},     /* Enclosed Alphanumerics. */
+    {0x2500, 0x257F, 43},     /* Box Drawing. */
+    {0x2580, 0x259F, 44},     /* Block Elements. */
+    {0x25A0, 0x25FF, 45},     /* Geometric Shapes. */
+    {0x2600, 0x26FF, 46},     /* Miscellaneous Symbols. */
+    {0x2700, 0x27BF, 47},     /* Dingbats. */
+    {0x27C0, 0x27EF, 38},     /* Mathematical Operators. */
+    {0x27F0, 0x27FF, 37},     /* Arrows. */
+    {0x2800, 0x28FF, 82},     /* Braille. */
+    {0x2900, 0x297F, 37},     /* Arrows. */
+    {0x2980, 0x2AFF, 38},     /* Mathematical Operators. */
+    {0x2B00, 0x2BFF, 37},     /* Arrows. */
+    {0x2C00, 0x2C5F, 97},     /* Glagolitic. */
+    {0x2C60, 0x2C7F, 29},     /* Latin Extended Additional. */
+    {0x2C80, 0x2CFF, 8},      /* Coptic. */
+    {0x2D00, 0x2D2F, 26},     /* Georgian. */
+    {0x2D30, 0x2D7F, 98},     /* Tifinagh. */
+    {0x2D80, 0x2DDF, 75},     /* Ethiopic. */
+    {0x2DE0, 0x2DFF, 9},      /* Cyrillic. */
+    {0x2E00, 0x2E7F, 31},     /* General Punctuation. */
+    {0x2E80, 0x2FFF, 59},     /* CJK Unified Ideographs. */
+    {0x3000, 0x303F, 48},     /* CJK Symbols And Punctuation. */
+    {0x3040, 0x309F, 49},     /* Hiragana. */
+    {0x30A0, 0x30FF, 50},     /* Katakana. */
+    {0x3100, 0x312F, 51},     /* Bopomofo. */
+    {0x3130, 0x318F, 52},     /* Hangul Compatibility Jamo. */
+    {0x3190, 0x319F, 59},     /* CJK Unified Ideographs. */
+    {0x31A0, 0x31BF, 51},     /* Bopomofo. */
+    {0x31C0, 0x31EF, 59},     /* CJK Unified Ideographs. */
+    {0x31F0, 0x31FF, 50},     /* Katakana. */
+    {0x3200, 0x32FF, 54},     /* Enclosed CJK Letters And Months. */
+    {0x3300, 0x33FF, 55},     /* CJK Compatibility. */
+    {0x3400, 0x4DBF, 59},     /* CJK Unified Ideographs. */
+    {0x4DC0, 0x4DFF, 99},     /* Yijing. */
+    {0x4E00, 0x9FFF, 59},     /* CJK Unified Ideographs. */
+    {0xA000, 0xA4CF, 83},     /* Yi. */
+    {0xA4D0, 0xA4FF, -1},     /* Lisu. */
+    {0xA500, 0xA63F, 12},     /* Vai. */
+    {0xA640, 0xA69F, 9},      /* Cyrillic. */
+    {0xA6A0, 0xA6FF, -1},     /* Bamum. */
+    {0xA700, 0xA71F, 5},      /* Spacing Modifier Letters. */
+    {0xA720, 0xA7FF, 29},     /* Latin Extended Additional. */
+    {0xA800, 0xA82F, 100},    /* Syloti Nagri. */
+    {0xA840, 0xA87F, 53},     /* Phags-pa. */
+    {0xA880, 0xA8DF, 115},    /* Saurashtra. */
+    {0xA900, 0xA92F, 116},    /* Kayah Li. */
+    {0xA930, 0xA95F, 117},    /* Rejang. */
+    {0xA960, 0xA97F, 56},     /* Hangul Syllables. */
+    {0xA980, 0xA9DF, -1},     /* Javanese. */
+    {0xA9E0, 0xA9FF, 74},     /* Myanmar. */
+    {0xAA00, 0xAA5F, 118},    /* Cham. */
+    {0xAA60, 0xAA7F, 74},     /* Myanmar. */
+    {0xAA80, 0xAADF, -1},     /* Tai Viet. */
+    {0xAAE0, 0xAAFF, -1},     /* Meetei Mayek. */
+    {0xAB00, 0xAB2F, 75},     /* Ethiopic. */
+    {0xAB70, 0xABBF, 76},     /* Cherokee. */
+    {0xABC0, 0xABFF, -1},     /* Meetei Mayek. */
+    {0xAC00, 0xD7AF, 56},     /* Hangul Syllables. */
+    {0xD800, 0xDFFF, 57},     /* Non-Plane 0. */
+    {0xE000, 0xF6FF, 60},     /* Private Use Area. */
+    {0xE700, 0xEFFF, -1},     /* MS Wingdings. */
+    {0xF000, 0xF8FF, -1},     /* MS Symbols. */
+    {0xF900, 0xFAFF, 61},     /* CJK Compatibility Ideographs. */
+    {0xFB00, 0xFB4F, 62},     /* Alphabetic Presentation Forms. */
+    {0xFB50, 0xFDFF, 63},     /* Arabic Presentation Forms-A. */
+    {0xFE00, 0xFE0F, 91},     /* Variation Selectors. */
+    {0xFE10, 0xFE1F, 65},     /* CJK Compatibility Forms. */
+    {0xFE20, 0xFE2F, 64},     /* Combining Half Marks. */
+    {0xFE30, 0xFE4F, 65},     /* CJK Compatibility Forms. */
+    {0xFE50, 0xFE6F, 66},     /* Small Form Variants. */
+    {0xFE70, 0xFEFF, 67},     /* Arabic Presentation Forms-B. */
+    {0xFF00, 0xFFEF, 68},     /* Halfwidth And Fullwidth Forms. */
+    {0xFFF0, 0xFFFF, 69},     /* Specials. */
+    {0x10000, 0x1013F, 101},  /* Linear B. */
+    {0x10140, 0x1018F, 102},  /* Ancient Greek Numbers. */
+    {0x10190, 0x101CF, 119},  /* Ancient Symbols. */
+    {0x101D0, 0x101FF, 120},  /* Phaistos Disc. */
+    {0x10280, 0x1029F, 121},  /* Lycian. */
+    {0x102A0, 0x102DF, 121},  /* Carian. */
+    {0x10300, 0x1032F, 85},   /* Old Italic. */
+    {0x10330, 0x1034F, 86},   /* Gothic. */
+    {0x10350, 0x1037F, -1},   /* Old Permic. */
+    {0x10380, 0x1039F, 103},  /* Ugaritic. */
+    {0x103A0, 0x103DF, 104},  /* Old Persian. */
+    {0x10400, 0x1044F, 87},   /* Deseret. */
+    {0x10450, 0x1047F, 105},  /* Shavian. */
+    {0x10480, 0x104AF, 106},  /* Osmanya. */
+    {0x104B0, 0x104FF, -1},   /* Osage. */
+    {0x10500, 0x1052F, -1},   /* Elbasan. */
+    {0x10530, 0x1056F, -1},   /* Caucasian Albanian. */
+    {0x10570, 0x105BF, -1},   /* Vithkuqi. */
+    {0x10600, 0x1077F, -1},   /* Linear A. */
+    {0x10780, 0x107BF, 3},    /* Latin Extended-B. */
+    {0x10800, 0x1083F, 107},  /* Cypriot Syllabary. */
+    {0x10840, 0x1085F, -1},   /* Imperial Aramaic. */
+    {0x10860, 0x1087F, -1},   /* Palmyrene. */
+    {0x10880, 0x108AF, -1},   /* Nabataean. */
+    {0x108E0, 0x108FF, -1},   /* Hatran. */
+    {0x10900, 0x1091F, 58},   /* Phoenician. */
+    {0x10920, 0x1093F, 121},  /* Lydian. */
+    {0x10980, 0x1099F, -1},   /* Meroitic Hieroglyphs. */
+    {0x109A0, 0x109FF, -1},   /* Meroitic Cursive. */
+    {0x10A00, 0x10A5F, 108},  /* Kharoshthi. */
+    {0x10A60, 0x10A7F, -1},   /* Old South Arabian. */
+    {0x10A80, 0x10A9F, -1},   /* Old North Arabian. */
+    {0x10AC0, 0x10AFF, -1},   /* Manichaean. */
+    {0x10B00, 0x10B3F, -1},   /* Avestan. */
+    {0x10B40, 0x10B5F, -1},   /* Inscriptional Parthian. */
+    {0x10B60, 0x10B7F, -1},   /* Inscriptional Pahlavi. */
+    {0x10B80, 0x10BAF, -1},   /* Psalter Pahlavi. */
+    {0x10C00, 0x10C4F, -1},   /* Old Turkic. */
+    {0x10C80, 0x10CFF, -1},   /* Old Hungarian. */
+    {0x10D00, 0x10D3F, -1},   /* Hanifi Rohingya. */
+    {0x108E0, 0x10E7F, -1},   /* Rumi Numeral Symbols. */
+    {0x10E80, 0x10EBF, -1},   /* Yezidi. */
+    {0x10F00, 0x10F2F, -1},   /* Old Sogdian. */
+    {0x10F30, 0x10F6F, -1},   /* Sogdian. */
+    {0x10F70, 0x10FAF, -1},   /* Old Uyghur. */
+    {0x10FB0, 0x10FDF, -1},   /* Chorasmian. */
+    {0x10FE0, 0x10FFF, -1},   /* Elymaic. */
+    {0x11000, 0x1107F, -1},   /* Brahmi. */
+    {0x11080, 0x110CF, -1},   /* Kaithi. */
+    {0x110D0, 0x110FF, -1},   /* Sora Sompeng. */
+    {0x11100, 0x1114F, -1},   /* Chakma. */
+    {0x11150, 0x1117F, -1},   /* Mahajani. */
+    {0x11180, 0x111DF, -1},   /* Sharada. */
+    {0x111E0, 0x111FF, -1},   /* Sinhala Archaic Numbers. */
+    {0x11200, 0x1124F, -1},   /* Khojki. */
+    {0x11280, 0x112AF, -1},   /* Multani. */
+    {0x112B0, 0x112FF, -1},   /* Khudawadi. */
+    {0x11300, 0x1137F, -1},   /* Grantha. */
+    {0x11400, 0x1147F, -1},   /* Newa. */
+    {0x11480, 0x114DF, -1},   /* Tirhuta. */
+    {0x11580, 0x115FF, -1},   /* Siddham. */
+    {0x11600, 0x1165F, -1},   /* Modi. */
+    {0x11660, 0x1167F, 81},   /* Mongolian. */
+    {0x11680, 0x116CF, -1},   /* Takri. */
+    {0x11700, 0x1174F, -1},   /* Ahom. */
+    {0x11800, 0x1184F, -1},   /* Dogra. */
+    {0x118A0, 0x118FF, -1},   /* Warang Citi. */
+    {0x11900, 0x1195F, -1},   /* Dives Akuru. */
+    {0x119A0, 0x119FF, -1},   /* Nandinagari. */
+    {0x11A00, 0x11A4F, -1},   /* Zanabazar Square. */
+    {0x11A50, 0x11AAF, -1},   /* Soyombo. */
+    {0x11AB0, 0x11ABF, 77},   /* Canadian Aboriginal Syllabics. */
+    {0x11AC0, 0x11AFF, -1},   /* Pau Cin Hau. */
+    {0x11C00, 0x11C6F, -1},   /* Bhaiksuki. */
+    {0x11C70, 0x11CBF, -1},   /* Marchen. */
+    {0x11D00, 0x11D5F, -1},   /* Masaram Gondi. */
+    {0x11D60, 0x11DAF, -1},   /* Gunjala Gondi. */
+    {0x11EE0, 0x11EFF, -1},   /* Makasar. */
+    {0x11FB0, 0x11FBF, -1},   /* Lisu. */
+    {0x11FC0, 0x11FFF, 20},   /* Tamil. */
+    {0x12000, 0x1254F, 110},  /* Cuneiform. */
+    {0x12F90, 0x12FFF, -1},   /* Cypro-Minoan. */
+    {0x13000, 0x1343F, -1},   /* Egyptian Hieroglyphs. */
+    {0x14400, 0x1467F, -1},   /* Anatolian Hieroglyphs. */
+    {0x16800, 0x16A3F, -1},   /* Bamum. */
+    {0x16A40, 0x16A6F, -1},   /* Mro. */
+    {0x16A70, 0x16ACF, -1},   /* Tangsa. */
+    {0x16AD0, 0x16AFF, -1},   /* Bassa Vah. */
+    {0x16B00, 0x16B8F, -1},   /* Pahawh Hmong. */
+    {0x16E40, 0x16E9F, -1},   /* Medefaidrin. */
+    {0x16F00, 0x16F9F, -1},   /* Miao. */
+    {0x16FE0, 0x16FFF, -1},   /* Ideographic Symbols. */
+    {0x17000, 0x18AFF, -1},   /* Tangut. */
+    {0x1B170, 0x1B2FF, -1},   /* Nushu. */
+    {0x1BC00, 0x1BC9F, -1},   /* Duployan. */
+    {0x1D000, 0x1D24F, 88},   /* Musical Symbols. */
+    {0x1D2E0, 0x1D2FF, -1},   /* Mayan Numerals. */
+    {0x1D300, 0x1D35F, 109},  /* Tai Xuan Jing. */
+    {0x1D360, 0x1D37F, 111},  /* Counting Rod Numerals. */
+    {0x1D400, 0x1D7FF, 89},   /* Mathematical Alphanumeric Symbols. */
+    {0x1E2C0, 0x1E2FF, -1},   /* Wancho. */
+    {0x1E800, 0x1E8DF, -1},   /* Mende Kikakui. */
+    {0x1E900, 0x1E95F, -1},   /* Adlam. */
+    {0x1EC70, 0x1ECBF, -1},   /* Indic Siyaq Numbers. */
+    {0x1F000, 0x1F02F, 122},  /* Mahjong Tiles. */
+    {0x1F030, 0x1F09F, 122},  /* Domino Tiles. */
+    {0x1F600, 0x1F64F, -1},   /* Emoticons. */
+    {0x20000, 0x2A6DF, 59},   /* CJK Unified Ideographs. */
+    {0x2F800, 0x2FA1F, 61},   /* CJK Compatibility Ideographs. */
+    {0xE0000, 0xE007F, 92},   /* Tags. */
+    {0xE0100, 0xE01EF, 91},   /* Variation Selectors. */
+    {0xF0000, 0x10FFFD, 90}}; /* Private Use Supplementary. */
+
+/* Find a unicode block that a charcode belongs to. */
+static eUnicodeBlock *blf_charcode_to_unicode_block(uint charcode)
+{
+  if (charcode < 0x80) {
+    /* Shortcut to Basic Latin. */
+    return &unicode_blocks[0];
+  }
+
+  /* Binary search for other blocks. */
+
+  int min = 0;
+  int max = ARRAY_SIZE(unicode_blocks) - 1;
+  int mid;
+
+  if (charcode < unicode_blocks[0].first || charcode > unicode_blocks[max].last) {
+    return NULL;
+  }
+
+  while (max >= min) {
+    mid = (min + max) / 2;
+    if (charcode > unicode_blocks[mid].last) {
+      min = mid + 1;
+    }
+    else if (charcode < unicode_blocks[mid].first) {
+      max = mid - 1;
+    }
+    else {
+      return &unicode_blocks[mid];
+    }
+  }
+
+  return NULL;
+}
+
+static int blf_charcode_to_coverage_bit(uint charcode)
+{
+  int coverage_bit = -1;
+  eUnicodeBlock *block = blf_charcode_to_unicode_block(charcode);
+  if (block) {
+    coverage_bit = block->coverage_bit;
+  }
+
+  if (coverage_bit < 0 && charcode > 0xFFFF) {
+    /* No coverage bit, but OpenType specs v.1.3+ says bit 57 implies that there
+     * are codepoints supported beyond the BMP, so only check fonts with this set. */
+    coverage_bit = 57;
+  }
+
+  return coverage_bit;
+}
+
+static bool blf_font_has_coverage_bit(FontBLF *font, int coverage_bit)
+{
+  if (coverage_bit < 0) {
+    return false;
+  }
+  return (font->UnicodeRanges[coverage_bit >> 5] & (1 << (coverage_bit % 32)));
+}
+
 /**
  * Return a glyph index from `charcode`. Not found returns zero, which is a valid
  * printable character (`.notdef` or `tofu`). Font is allowed to change here.
@@ -229,8 +559,42 @@ static GlyphBLF *blf_glyph_cache_add_glyph(
 static FT_UInt blf_glyph_index_from_charcode(FontBLF **font, const uint charcode)
 {
   FT_UInt glyph_index = FT_Get_Char_Index((*font)->face, charcode);
-  /* TODO: If not found in this font, check others, update font pointer. */
-  return glyph_index;
+  if (glyph_index) {
+    return glyph_index;
+  }
+
+  /* Not found in main font, so look in the others. */
+  FontBLF *last_resort = NULL;
+  int coverage_bit = blf_charcode_to_coverage_bit(charcode);
+  for (int i = 0; i < BLF_MAX_FONT; i++) {
+    FontBLF *f = global_font[i];
+    if (!f || f == *font || !(f->flags & BLF_DEFAULT)) {
+      continue;
+    }
+
+    if (f->flags & BLF_LAST_RESORT) {
+      last_resort = f;
+      continue;
+    }
+    if (coverage_bit < 0 || blf_font_has_coverage_bit(f, coverage_bit)) {
+      glyph_index = FT_Get_Char_Index(f->face, charcode);
+      if (glyph_index) {
+        *font = f;
+        return glyph_index;
+      }
+    }
+  }
+
+  /* Not found in the stack, return from Last Resort if there is one. */
+  if (last_resort) {
+    glyph_index = FT_Get_Char_Index(last_resort->face, charcode);
+    if (glyph_index) {
+      *font = last_resort;
+      return glyph_index;
+    }
+  }
+
+  return 0;
 }
 
 /**
@@ -377,24 +741,24 @@ static bool UNUSED_FUNCTION(blf_glyph_transform_width)(FT_GlyphSlot glyph, float
 /**
  * Transform glyph to fit nicely within a fixed column width.
  */
-static bool UNUSED_FUNCTION(blf_glyph_transform_monospace)(FT_GlyphSlot glyph, int width)
+static bool blf_glyph_transform_monospace(FT_GlyphSlot glyph, int width)
 {
   if (glyph->format == FT_GLYPH_FORMAT_OUTLINE) {
-    int gwidth = (int)(glyph->linearHoriAdvance >> 16);
-    if (gwidth > width) {
-      float scale = (float)width / (float)gwidth;
+    FT_Fixed current = glyph->linearHoriAdvance;
+    FT_Fixed target = width << 16; /* Do math in 16.16 values. */
+    if (target < current) {
+      const FT_Pos embolden = (FT_Pos)((current - target) >> 13);
+      /* Horizontally widen strokes to counteract narrowing. */
+      FT_Outline_EmboldenXY(&glyph->outline, embolden, 0);
+      const float scale = (float)(target - (embolden << 9)) / (float)current;
       FT_Matrix matrix = {to_16dot16(scale), 0, 0, to_16dot16(1)};
-      /* Narrowing all points also thins vertical strokes. */
       FT_Outline_Transform(&glyph->outline, &matrix);
-      const FT_Pos extra_x = (int)((float)(gwidth - width) * 5.65f);
-      /* Horizontally widen strokes to counteract narrowing. */
-      FT_Outline_EmboldenXY(&glyph->outline, extra_x, 0);
     }
-    else if (gwidth < width) {
-      /* Narrow glyphs only need to be centered. */
-      int nudge = (width - gwidth) / 2;
-      FT_Outline_Translate(&glyph->outline, (FT_Pos)nudge * 64, 0);
+    else if (target > current) {
+      /* Center narrow glyphs. */
+      FT_Outline_Translate(&glyph->outline, (FT_Pos)((target - current) >> 11), 0);
     }
+    glyph->advance.x = width << 6;
     return true;
   }
   return false;
@@ -411,7 +775,9 @@ static bool UNUSED_FUNCTION(blf_glyph_transform_monospace)(FT_GlyphSlot glyph, i
  */
 static FT_GlyphSlot blf_glyph_render(FontBLF *settings_font,
                                      FontBLF *glyph_font,
-                                     FT_UInt glyph_index)
+                                     FT_UInt glyph_index,
+                                     uint charcode,
+                                     int fixed_width)
 {
   if (glyph_font != settings_font) {
     FT_Set_Char_Size(glyph_font->face,
@@ -428,6 +794,10 @@ static FT_GlyphSlot blf_glyph_render(FontBLF *settings_font,
     return NULL;
   }
 
+  if ((settings_font->flags & BLF_MONOSPACED) && (settings_font != glyph_font)) {
+    blf_glyph_transform_monospace(glyph, BLI_wcwidth((char32_t)charcode) * fixed_width);
+  }
+
   if ((settings_font->flags & BLF_ITALIC) != 0) {
     /* 37.5% of maximum rightward slant results in 6 degree slope, matching italic
      * version (`DejaVuSans-Oblique.ttf`) of our current font. But a nice median when
@@ -466,7 +836,8 @@ GlyphBLF *blf_glyph_ensure(FontBLF *font, GlyphCacheBLF *gc, uint charcode)
    * renderer uses a shared buffer internally. */
   BLI_spin_lock(font_with_glyph->ft_lib_mutex);
 
-  FT_GlyphSlot glyph = blf_glyph_render(font, font_with_glyph, glyph_index);
+  FT_GlyphSlot glyph = blf_glyph_render(
+      font, font_with_glyph, glyph_index, charcode, gc->fixed_width);
 
   if (glyph) {
     /* Save this glyph in the initial font's cache. */
diff --git a/source/blender/blenfont/intern/blf_internal.h b/source/blender/blenfont/intern/blf_internal.h
index 7754f960043..84037ff4bd0 100644
--- a/source/blender/blenfont/intern/blf_internal.h
+++ b/source/blender/blenfont/intern/blf_internal.h
@@ -14,6 +14,12 @@ struct ResultBLF;
 struct rctf;
 struct rcti;
 
+/* Max number of fonts in memory. Take care that every font has a glyph cache per size/dpi,
+ * so we don't need load the same font with different size, just load one and call BLF_size. */
+#define BLF_MAX_FONT 32
+
+extern struct FontBLF *global_font[BLF_MAX_FONT];
+
 void blf_batch_draw_begin(struct FontBLF *font);
 void blf_batch_draw(void);
 
diff --git a/source/blender/blenfont/intern/blf_internal_types.h b/source/blender/blenfont/intern/blf_internal_types.h
index 9dfcb1a4ad6..998093dae70 100644
--- a/source/blender/blenfont/intern/blf_internal_types.h
+++ b/source/blender/blenfont/intern/blf_internal_types.h
@@ -226,6 +226,11 @@ typedef struct FontBLF {
   /** File-path or NULL. */
   char *filepath;
 
+  /* Copied from the SFNT OS/2 table. Bit flags for unicode blocks and ranges
+   * considered "functional". Cached here because face might not always exist.
+   * See: https://docs.microsoft.com/en-us/typography/opentype/spec/os2#ur */
+  uint UnicodeRanges[4];
+
   /* aspect ratio or scale. */
   float aspect[3];
 
diff --git a/source/blender/blenlib/intern/string_utf8.c b/source/blender/blenlib/intern/string_utf8.c
index 94efb0dd9e7..0cbf62cce03 100644
--- a/source/blender/blenlib/intern/string_utf8.c
+++ b/source/blender/blenlib/intern/string_utf8.c
@@ -363,6 +363,10 @@ size_t BLI_strncpy_wchar_from_utf8(wchar_t *__restrict dst_w,
 
 int BLI_wcwidth(char32_t ucs)
 {
+  /* Treat private use areas (icon fonts), symbols, and emoticons as double-width. */
+  if (ucs >= 0xf0000 || (ucs >= 0xe000 && ucs < 0xf8ff) || (ucs >= 0x1f300 && ucs < 0x1fbff)) {
+    return 2;
+  }
   return mk_wcwidth(ucs);
 }
 
diff --git a/source/blender/editors/interface/interface_style.cc b/source/blender/editors/interface/interface_style.cc
index 291ede05730..904765f6dc4 100644
--- a/source/blender/editors/interface/interface_style.cc
+++ b/source/blender/editors/interface/interface_style.cc
@@ -382,19 +382,8 @@ void uiStyleInit(void)
   }
   CLAMP(U.dpi, 48, 144);
 
-  LISTBASE_FOREACH (uiFont *, font, &U.uifonts) {
-    BLF_unload_id(font->blf_id);
-  }
-
-  if (blf_mono_font != -1) {
-    BLF_unload_id(blf_mono_font);
-    blf_mono_font = -1;
-  }
-
-  if (blf_mono_font_render != -1) {
-    BLF_unload_id(blf_mono_font_render);
-    blf_mono_font_render = -1;
-  }
+  /* Needed so that custom fonts are always first. */
+  BLF_unload_all();
 
   uiFont *font_first = static_cast<uiFont *>(U.uifonts.first);
 
@@ -498,6 +487,9 @@ void uiStyleInit(void)
     const bool unique = true;
     blf_mono_font_render = BLF_load_mono_default(unique);
   }
+
+  /* Load the fallback fonts last. */
+  BLF_load_font_stack();
 }
 
 void UI_fontstyle_set(const uiFontStyle *fs)
diff --git a/source/blender/windowmanager/intern/wm_playanim.c b/source/blender/windowmanager/intern/wm_playanim.c
index 3100e6e4fd3..9c97b05f79b 100644
--- a/source/blender/windowmanager/intern/wm_playanim.c
+++ b/source/blender/windowmanager/intern/wm_playanim.c
@@ -1555,6 +1555,7 @@ static char *wm_main_playanim_intern(int argc, const char **argv)
 
   /* initialize the font */
   BLF_init();
+  BLF_load_font_stack();
   ps.fontid = BLF_load_mono_default(false);
   BLF_size(ps.fontid, 11.0f, 72);