Merge pull request #6324 from Sokigo-GLS/branch-allow-missing-glyph

Try to fallback to using a question mark if a glyph is missing in a font

fontcache.c

@@ -287,8 +287,14 @@ glyph_element* msGetGlyphByIndex(face_element *face, unsigned int size, unsigned
       FT_Set_Pixel_Sizes(face->face,0,MS_NINT(size * 96/72.0));
     }
     error = FT_Load_Glyph(face->face,key.codepoint,FT_LOAD_DEFAULT|FT_LOAD_NO_BITMAP|FT_LOAD_NO_HINTING|FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH);
+    if (error) {
+      msDebug("Unable to load glyph %u for font \"%s\". Using ? as fallback.\n", key.codepoint, face->font);
+      // If we can't find a glyph then try to fallback to a question mark.
+      unsigned int fallbackCodepoint = msGetGlyphIndex(face, 0x3F);
+      error = FT_Load_Glyph(face->face,fallbackCodepoint,FT_LOAD_DEFAULT|FT_LOAD_NO_BITMAP|FT_LOAD_NO_HINTING|FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH);
+    }
     if(error) {
-      msSetError(MS_MISCERR, "unable to load glyph %ud for font \"%s\"", "msGetGlyphByIndex()",key.codepoint, face->font);
+      msSetError(MS_MISCERR, "unable to load glyph %u for font \"%s\"", "msGetGlyphByIndex()",key.codepoint, face->font);
       free(gc);
 #ifdef USE_THREAD
       if (use_global_ft_cache)
@@ -335,8 +341,14 @@ outline_element* msGetGlyphOutline(face_element *face, glyph_element *glyph) {
     pen.x = pen.y = 0;
     FT_Set_Transform(face->face, &matrix, &pen);
     error = FT_Load_Glyph(face->face,glyph->key.codepoint,FT_LOAD_DEFAULT|FT_LOAD_NO_BITMAP/*|FT_LOAD_IGNORE_TRANSFORM*/|FT_LOAD_NO_HINTING|FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH);
+    if (error) {
+      msDebug("Unable to load glyph %u for font \"%s\". Using ? as fallback.\n", glyph->key.codepoint, face->font);
+      // If we can't find a glyph then try to fallback to a question mark.
+      unsigned int fallbackCodepoint = msGetGlyphIndex(face, 0x3F);
+      error = FT_Load_Glyph(face->face,fallbackCodepoint,FT_LOAD_DEFAULT|FT_LOAD_NO_BITMAP/*|FT_LOAD_IGNORE_TRANSFORM*/|FT_LOAD_NO_HINTING|FT_LOAD_IGNORE_GLOBAL_ADVANCE_WIDTH);
+    }
     if(error) {
-      msSetError(MS_MISCERR, "unable to load glyph %ud for font \"%s\"", "msGetGlyphByIndex()",glyph->key.codepoint, face->font);
+      msSetError(MS_MISCERR, "unable to load glyph %u for font \"%s\"", "msGetGlyphOutline()",glyph->key.codepoint, face->font);
 #ifdef USE_THREAD
       if (use_global_ft_cache)
         msReleaseLock(TLOCK_TTF);

msautotest/renderers/font-fail.map

@@ -1,5 +1,6 @@
 # RUN_PARMS: font-fail-key.txt [MAPSERV] QUERY_STRING="map=[MAPFILE]&mode=map&layer=l1" > [RESULT_DEVERSION]
 # RUN_PARMS: font-fail-file.txt [MAPSERV] QUERY_STRING="map=[MAPFILE]&mode=map&layer=l2" > [RESULT_DEVERSION]
+# RUN_PARMS: font-fail-missing-glyph.png [SHP2IMG] -m [MAPFILE] -l missing_glyph -i png -o [RESULT]
 
 MAP
 
@@ -41,4 +42,21 @@ LAYER
  FEATURE POINTS 50 50 END END
 END
 
+LAYER
+    NAME "missing_glyph"
+    STATUS ON
+    TYPE POLYGON
+    FEATURE
+      POINTS 0 0 400 0 400 300 0 300 0 0 END
+    END
+    CLASS
+        LABEL
+            TEXT 'this is a test: это проверка'
+            TYPE truetype
+            SIZE 8
+            FONT "default"
+        END
+    END
+END
+
 END

textlayout.c

@@ -242,7 +242,7 @@ static hb_position_t _ms_get_glyph_v_advance_func (hb_font_t *font, void *font_d
 }
 #endif
 
-int WARN_UNUSED check_single_font(fontSetObj *fontset, char *fontkey, text_run *run, TextInfo *glyphs, int ignore_missing) {
+static int check_single_font(fontSetObj *fontset, char *fontkey, text_run *run, TextInfo *glyphs, int ignore_missing) {
   int i;
   face_element *fcache = NULL;
   if(fontset && fontkey) {
@@ -256,16 +256,23 @@ int WARN_UNUSED check_single_font(fontSetObj *fontset, char *fontkey, text_run *
   run->face = fcache;
   if(MS_UNLIKELY(!fcache)) return MS_FAILURE;
   for(i=0; i<run->length; i++) {
-    int codepoint = msGetGlyphIndex(fcache, glyphs->unicodes[run->offset+i]);
+    unsigned int codepoint = msGetGlyphIndex(fcache, glyphs->unicodes[run->offset+i]);
     if(codepoint || ignore_missing)
+    {
+      if( codepoint == 0 )
+      {
+          msDebug("Unable to find glyph for codepoint %u. Using ? as fallback.\n", glyphs->unicodes[run->offset+i]);
+          codepoint = msGetGlyphIndex(fcache, '?');
+      }
       glyphs->codepoints[run->offset+i] = codepoint;
+    }
     else
       return MS_FAILURE;
   }
   return MS_SUCCESS;
 }
 
-int WARN_UNUSED get_face_for_run(fontSetObj *fontset, char *fontlist, text_run *run, TextInfo *glyphs) {
+static int get_face_for_run(fontSetObj *fontset, char *fontlist, text_run *run, TextInfo *glyphs) {
   char *startfont, *endfont;
 #if defined(USE_HARFBUZZ) && defined(USE_FRIBIDI)
   const char *prefix = NULL;