From 419a0b803c0663490258cb1f6f23d2334cd08489 Mon Sep 17 00:00:00 2001
From: Fabian Greffrath <fabian@greffrath.com>
Date: Mon, 25 Aug 2014 18:21:32 +0200
Subject: [PATCH] if glyph name lookup failed, try alternate naming scheme for
 ligatures

According to the Adobe spec., ligature glyphs may be named either e.g.
"fi" ot "f_i". If text has been set with a font using the one naming
scheme but is rendered with a font using the other, ligature glyphs
may be missing from the rendering. Therefore, if a glyph name lookup
failed, try again using the other naming scheme.

This happened e.g. for the "fl" and "fi" ligatures in texts set in
Times but rendered in Tex Gyre Termes.

Closes Bug #73291, Bug #80093.
---
 poppler/CairoFontEngine.cc | 41 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/poppler/CairoFontEngine.cc b/poppler/CairoFontEngine.cc
index 1546594..c30c7da 100644
--- a/poppler/CairoFontEngine.cc
+++ b/poppler/CairoFontEngine.cc
@@ -458,6 +458,47 @@ CairoFreeTypeFont *CairoFreeTypeFont::create(GfxFont *gfxFont, XRef *xref,
       codeToGID[i] = 0;
       if ((name = enc[i])) {
 	codeToGID[i] = FT_Get_Name_Index(face, name);
+
+	// glyph lookup failed, try alternate naming scheme for ligatures
+	if (!codeToGID[i])
+	{
+	  size_t j, k;
+	  char newname[14];
+	  const size_t namelen = strlen(name);
+
+	  // unusual glyph name size for a ligature
+	  if (namelen < 2 || namelen > 7)
+		continue;
+
+	  if (!strchr(name, '_'))
+	  {
+	    // glyph name contains no underscores,
+	    // now try with interleaving them
+	    newname[0] = name[0];
+	    for (j = k = 1; j < namelen; j++)
+	    {
+	      newname[k++] = '_';
+	      newname[k++] = name[j];
+	    }
+	    newname[k] = '\0';
+	  }
+	  else
+	  {
+	    // glyph name already contains underscores,
+	    // now try without them
+	    for (j = k = 0; j < namelen; j++)
+	    {
+	      if (name[j] != '_')
+	      {
+		newname[k++] = name[j];
+	      }
+	    }
+	    newname[k] = '\0';
+	  }
+
+	  // repeat glyph lookup for the alternate name
+	  codeToGID[i] = FT_Get_Name_Index(face, newname);
+	}
       }
     }
     break;
-- 
2.1.0