Adding upstream version 2.10.36.upstream/2.10.36

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 820 insertions, 0 deletions

diff --git a/app/text/gimpfont.c b/app/text/gimpfont.c
new file mode 100644
index 0000000..148275d
--- /dev/null
+++ b/app/text/gimpfont.c
@@ -0,0 +1,820 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995 Spencer Kimball and Peter Mattis
+ *
+ * gimpfont.c
+ * Copyright (C) 2003 Michael Natterer <mitch@gimp.org>
+ *                    Sven Neumann <sven@gimp.org>
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <gdk-pixbuf/gdk-pixbuf.h>
+#include <gegl.h>
+
+#include <pango/pangocairo.h>
+
+#include <hb.h>
+#include <hb-ot.h>
+#include <hb-ft.h>
+
+#define PANGO_ENABLE_ENGINE  1   /* Argh */
+#include <pango/pango-ot.h>
+
+#include <ft2build.h>
+#include FT_TRUETYPE_TABLES_H
+
+#include "text-types.h"
+
+#include "core/gimptempbuf.h"
+
+#include "gimpfont.h"
+
+#include "gimp-intl.h"
+
+
+/* This is a so-called pangram; it's supposed to
+   contain all characters found in the alphabet. */
+#define GIMP_TEXT_PANGRAM     N_("Pack my box with\nfive dozen liquor jugs.")
+
+#define GIMP_FONT_POPUP_SIZE  (PANGO_SCALE * 30)
+
+#define DEBUGPRINT(x) /* g_print x */
+
+enum
+{
+  PROP_0,
+  PROP_PANGO_CONTEXT
+};
+
+
+struct _GimpFont
+{
+  GimpData      parent_instance;
+
+  PangoContext *pango_context;
+
+  PangoLayout  *popup_layout;
+  gint          popup_width;
+  gint          popup_height;
+};
+
+struct _GimpFontClass
+{
+  GimpDataClass   parent_class;
+};
+
+
+static void          gimp_font_constructed      (GObject       *object);
+static void          gimp_font_finalize         (GObject       *object);
+static void          gimp_font_set_property     (GObject       *object,
+                                                 guint          property_id,
+                                                 const GValue  *value,
+                                                 GParamSpec    *pspec);
+
+static void          gimp_font_get_preview_size (GimpViewable  *viewable,
+                                                 gint           size,
+                                                 gboolean       popup,
+                                                 gboolean       dot_for_dot,
+                                                 gint          *width,
+                                                 gint          *height);
+static gboolean      gimp_font_get_popup_size   (GimpViewable  *viewable,
+                                                 gint           width,
+                                                 gint           height,
+                                                 gboolean       dot_for_dot,
+                                                 gint          *popup_width,
+                                                 gint          *popup_height);
+static GimpTempBuf * gimp_font_get_new_preview  (GimpViewable  *viewable,
+                                                 GimpContext   *context,
+                                                 gint           width,
+                                                 gint           height);
+
+static const gchar * gimp_font_get_sample_string (PangoContext         *context,
+                                                  PangoFontDescription *font_desc);
+
+
+G_DEFINE_TYPE (GimpFont, gimp_font, GIMP_TYPE_DATA)
+
+#define parent_class gimp_font_parent_class
+
+
+static void
+gimp_font_class_init (GimpFontClass *klass)
+{
+  GObjectClass      *object_class   = G_OBJECT_CLASS (klass);
+  GimpViewableClass *viewable_class = GIMP_VIEWABLE_CLASS (klass);
+
+  object_class->constructed         = gimp_font_constructed;
+  object_class->finalize            = gimp_font_finalize;
+  object_class->set_property        = gimp_font_set_property;
+
+  viewable_class->get_preview_size  = gimp_font_get_preview_size;
+  viewable_class->get_popup_size    = gimp_font_get_popup_size;
+  viewable_class->get_new_preview   = gimp_font_get_new_preview;
+
+  viewable_class->default_icon_name = "gtk-select-font";
+
+  g_object_class_install_property (object_class, PROP_PANGO_CONTEXT,
+                                   g_param_spec_object ("pango-context",
+                                                        NULL, NULL,
+                                                        PANGO_TYPE_CONTEXT,
+                                                        GIMP_PARAM_WRITABLE));
+}
+
+static void
+gimp_font_init (GimpFont *font)
+{
+}
+
+static void
+gimp_font_constructed (GObject *object)
+{
+  G_OBJECT_CLASS (parent_class)->constructed (object);
+
+  gimp_data_make_internal (GIMP_DATA (object),
+                           gimp_object_get_name (object));
+}
+
+static void
+gimp_font_finalize (GObject *object)
+{
+  GimpFont *font = GIMP_FONT (object);
+
+  g_clear_object (&font->pango_context);
+  g_clear_object (&font->popup_layout);
+
+  G_OBJECT_CLASS (parent_class)->finalize (object);
+}
+
+static void
+gimp_font_set_property (GObject       *object,
+                        guint          property_id,
+                        const GValue  *value,
+                        GParamSpec    *pspec)
+{
+  GimpFont *font = GIMP_FONT (object);
+
+  switch (property_id)
+    {
+    case PROP_PANGO_CONTEXT:
+      if (font->pango_context)
+        g_object_unref (font->pango_context);
+      font->pango_context = g_value_dup_object (value);
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+      break;
+    }
+}
+
+static void
+gimp_font_get_preview_size (GimpViewable *viewable,
+                            gint          size,
+                            gboolean      popup,
+                            gboolean      dot_for_dot,
+                            gint         *width,
+                            gint         *height)
+{
+  *width  = size;
+  *height = size;
+}
+
+static gboolean
+gimp_font_get_popup_size (GimpViewable *viewable,
+                          gint          width,
+                          gint          height,
+                          gboolean      dot_for_dot,
+                          gint         *popup_width,
+                          gint         *popup_height)
+{
+  GimpFont             *font = GIMP_FONT (viewable);
+  PangoFontDescription *font_desc;
+  PangoRectangle        ink;
+  PangoRectangle        logical;
+  const gchar          *name;
+
+  if (! font->pango_context)
+    return FALSE;
+
+  name = gimp_object_get_name (font);
+
+  font_desc = pango_font_description_from_string (name);
+  g_return_val_if_fail (font_desc != NULL, FALSE);
+
+  pango_font_description_set_size (font_desc, GIMP_FONT_POPUP_SIZE);
+
+  if (font->popup_layout)
+    g_object_unref (font->popup_layout);
+
+  font->popup_layout = pango_layout_new (font->pango_context);
+  pango_layout_set_font_description (font->popup_layout, font_desc);
+  pango_font_description_free (font_desc);
+
+  pango_layout_set_text (font->popup_layout, gettext (GIMP_TEXT_PANGRAM), -1);
+  pango_layout_get_pixel_extents (font->popup_layout, &ink, &logical);
+
+  *popup_width  = MAX (ink.width,  logical.width)  + 6;
+  *popup_height = MAX (ink.height, logical.height) + 6;
+
+  *popup_width = cairo_format_stride_for_width (CAIRO_FORMAT_A8, *popup_width);
+
+  font->popup_width  = *popup_width;
+  font->popup_height = *popup_height;
+
+  return TRUE;
+}
+
+static GimpTempBuf *
+gimp_font_get_new_preview (GimpViewable *viewable,
+                           GimpContext  *context,
+                           gint          width,
+                           gint          height)
+{
+  GimpFont        *font = GIMP_FONT (viewable);
+  PangoLayout     *layout;
+  PangoRectangle   ink;
+  PangoRectangle   logical;
+  gint             layout_width;
+  gint             layout_height;
+  gint             layout_x;
+  gint             layout_y;
+  GimpTempBuf     *temp_buf;
+  cairo_t         *cr;
+  cairo_surface_t *surface;
+
+  if (! font->pango_context)
+    return NULL;
+
+  if (! font->popup_layout ||
+      font->popup_width != width || font->popup_height != height)
+    {
+      PangoFontDescription *font_desc;
+      const gchar          *name;
+
+      name = gimp_object_get_name (font);
+
+      DEBUGPRINT (("%s: ", name));
+
+      font_desc = pango_font_description_from_string (name);
+      g_return_val_if_fail (font_desc != NULL, NULL);
+
+      pango_font_description_set_size (font_desc,
+                                       PANGO_SCALE * height * 2.0 / 3.0);
+
+      layout = pango_layout_new (font->pango_context);
+
+      pango_layout_set_font_description (layout, font_desc);
+      pango_layout_set_text (layout,
+                             gimp_font_get_sample_string (font->pango_context,
+                                                          font_desc),
+                             -1);
+
+      pango_font_description_free (font_desc);
+    }
+  else
+    {
+      layout = g_object_ref (font->popup_layout);
+    }
+
+  width = cairo_format_stride_for_width (CAIRO_FORMAT_A8, width);
+
+  temp_buf = gimp_temp_buf_new (width, height, babl_format ("Y' u8"));
+  memset (gimp_temp_buf_get_data (temp_buf), 255, width * height);
+
+  surface = cairo_image_surface_create_for_data (gimp_temp_buf_get_data (temp_buf),
+                                                 CAIRO_FORMAT_A8,
+                                                 width, height, width);
+
+  pango_layout_get_pixel_extents (layout, &ink, &logical);
+
+  layout_width  = MAX (ink.width,  logical.width);
+  layout_height = MAX (ink.height, logical.height);
+
+  layout_x = (width - layout_width)  / 2;
+  layout_y = (height - layout_height) / 2;
+
+  if (ink.x < logical.x)
+    layout_x += logical.x - ink.x;
+
+  if (ink.y < logical.y)
+    layout_y += logical.y - ink.y;
+
+  cr = cairo_create (surface);
+
+  cairo_translate (cr, layout_x, layout_y);
+  cairo_set_operator (cr, CAIRO_OPERATOR_CLEAR);
+  pango_cairo_show_layout (cr, layout);
+
+  cairo_destroy (cr);
+  cairo_surface_destroy (surface);
+
+  g_object_unref (layout);
+
+  return temp_buf;
+}
+
+GimpData *
+gimp_font_get_standard (void)
+{
+  static GimpData *standard_font = NULL;
+
+  if (! standard_font)
+    {
+      standard_font = g_object_new (GIMP_TYPE_FONT,
+                                    "name", "",
+                                    NULL);
+
+      gimp_data_clean (standard_font);
+      gimp_data_make_internal (standard_font, "gimp-font-standard");
+
+      g_object_add_weak_pointer (G_OBJECT (standard_font),
+                                 (gpointer *) &standard_font);
+    }
+
+  return standard_font;
+}
+
+
+static inline gboolean
+gimp_font_covers_string (PangoFcFont *font,
+                         const gchar *sample)
+{
+  const gchar *p;
+
+  for (p = sample; *p; p = g_utf8_next_char (p))
+    {
+      if (! pango_fc_font_has_char (font, g_utf8_get_char (p)))
+        return FALSE;
+    }
+
+  return TRUE;
+}
+
+/* This function was picked up from Pango's pango-ot-info.c. Until there
+ * is a better way to get the tag, we use this.
+ */
+static hb_tag_t
+get_hb_table_type (PangoOTTableType table_type)
+{
+  switch (table_type)
+    {
+    case PANGO_OT_TABLE_GSUB:
+      return HB_OT_TAG_GSUB;
+    case PANGO_OT_TABLE_GPOS:
+      return HB_OT_TAG_GPOS;
+    default:
+      return HB_TAG_NONE;
+    }
+}
+
+/* Guess a suitable short sample string for the font. */
+static const gchar *
+gimp_font_get_sample_string (PangoContext         *context,
+                             PangoFontDescription *font_desc)
+{
+  PangoFont        *font;
+  hb_face_t        *hb_face;
+  FT_Face           face;
+  TT_OS2           *os2;
+  PangoOTTableType  tt;
+  gint              i;
+
+  /* This is a table of scripts and corresponding short sample strings
+   * to be used instead of the Latin sample string Aa. The script
+   * codes are as in ISO15924 (see
+   * https://www.unicode.org/iso15924/iso15924-codes.html), but in
+   * lower case. The Unicode subrange bit numbers, as used in TrueType
+   * so-called OS/2 tables, are from
+   * https://www.microsoft.com/typography/otspec/os2.htm#ur .
+   *
+   * The table is mostly ordered by Unicode order. But as there are
+   * fonts that support several of these scripts, the ordering is
+   * be modified so that the script which such a font is more likely
+   * to be actually designed for comes first and matches.
+   *
+   * These sample strings are mostly just guesswork as for their
+   * usefulness. Usually they contain what I assume is the first
+   * letter in the corresponding alphabet, or two first letters if the
+   * first one happens to look too "trivial" to be recognizable by
+   * itself.
+   *
+   * This table is used to determine the primary script a font has
+   * been designed for.
+   *
+   * Very useful link: https://www.wazu.jp/index.html
+   */
+  static const struct
+  {
+    const gchar  script[4];
+    gint         bit;
+    const gchar *sample;
+  } scripts[] = {
+    /* Han is first because fonts that support it presumably are primarily
+     * designed for it.
+     */
+    {
+      "hani",                   /* Han Ideographic */
+      59,
+      "\346\260\270"            /* U+6C38 "forever". Ed Trager says
+                                 * this is a "pan-stroke" often used
+                                 * in teaching Chinese calligraphy. It
+                                 * contains the eight basic Chinese
+                                 * stroke forms.
+                                 */
+    },
+    {
+      "copt",                   /* Coptic */
+      7,
+      "\316\221\316\261"        /* U+0410 GREEK CAPITAL LETTER ALPHA
+                                   U+0430 GREEK SMALL LETTER ALPHA
+                                 */
+    },
+    {
+      "grek",                   /* Greek */
+      7,
+      "\316\221\316\261"        /* U+0410 GREEK CAPITAL LETTER ALPHA
+                                   U+0430 GREEK SMALL LETTER ALPHA
+                                 */
+    },
+    {
+      "cyrl",                   /* Cyrillic */
+      9,
+      "\320\220\325\260"        /* U+0410 CYRILLIC CAPITAL LETTER A
+                                   U+0430 CYRILLIC SMALL LETTER A
+                                 */
+    },
+    {
+      "armn",                   /* Armenian */
+      10,
+      "\324\261\325\241"        /* U+0531 ARMENIAN CAPITAL LETTER AYB
+                                   U+0561 ARMENIAN SMALL LETTER AYB
+                                 */
+    },
+    {
+      "hebr",                   /* Hebrew */
+      11,
+      "\327\220"                /* U+05D0 HEBREW LETTER ALEF */
+    },
+    {
+      "arab",                   /* Arabic */
+      13,
+      "\330\247\330\250"        /* U+0627 ARABIC LETTER ALEF
+                                 * U+0628 ARABIC LETTER BEH
+                                 */
+    },
+    {
+      "syrc",                   /* Syriac */
+      71,
+      "\334\220\334\222"        /* U+0710 SYRIAC LETTER ALAPH
+                                 * U+0712 SYRIAC LETTER BETH
+                                 */
+    },
+    {
+      "thaa",                   /* Thaana */
+      72,
+      "\336\200\336\201"        /* U+0780 THAANA LETTER HAA
+                                 * U+0781 THAANA LETTER SHAVIYANI
+                                 */
+    },
+    /* Should really use some better sample strings for the complex
+     * scripts. Something that shows how well the font handles the
+     * complex processing for each script.
+     */
+    {
+      "deva",                   /* Devanagari */
+      15,
+      "\340\244\205"            /* U+0905 DEVANAGARI LETTER A*/
+    },
+    {
+      "beng",                   /* Bengali */
+      16,
+      "\340\246\205"            /* U+0985 BENGALI LETTER A */
+    },
+    {
+      "guru",                   /* Gurmukhi */
+      17,
+      "\340\250\205"            /* U+0A05 GURMUKHI LETTER A */
+    },
+    {
+      "gujr",                   /* Gujarati */
+      18,
+      "\340\252\205"            /* U+0A85 GUJARATI LETTER A */
+    },
+    {
+      "orya",                   /* Oriya */
+      19,
+      "\340\254\205"            /* U+0B05 ORIYA LETTER A */
+    },
+    {
+      "taml",                   /* Tamil */
+      20,
+      "\340\256\205"            /* U+0B85 TAMIL LETTER A */
+    },
+    {
+      "telu",                   /* Telugu */
+      21,
+      "\340\260\205"            /* U+0C05 TELUGU LETTER A */
+    },
+    {
+      "knda",                   /* Kannada */
+      22,
+      "\340\262\205"            /* U+0C85 KANNADA LETTER A */
+    },
+    {
+      "mylm",                   /* Malayalam */
+      23,
+      "\340\264\205"            /* U+0D05 MALAYALAM LETTER A */
+    },
+    {
+      "sinh",                   /* Sinhala */
+      73,
+      "\340\266\205"            /* U+0D85 SINHALA LETTER AYANNA */
+    },
+    {
+      "thai",                   /* Thai */
+      24,
+      "\340\270\201\340\270\264"/* U+0E01 THAI CHARACTER KO KAI
+                                 * U+0E34 THAI CHARACTER SARA I
+                                 */
+    },
+    {
+      "laoo",                   /* Lao */
+      25,
+      "\340\272\201\340\272\264"/* U+0E81 LAO LETTER KO
+                                 * U+0EB4 LAO VOWEL SIGN I
+                                 */
+    },
+    {
+      "tibt",                   /* Tibetan */
+      70,
+      "\340\274\200"            /* U+0F00 TIBETAN SYLLABLE OM */
+    },
+    {
+      "mymr",                   /* Myanmar */
+      74,
+      "\341\200\200"            /* U+1000 MYANMAR LETTER KA */
+    },
+    {
+      "geor",                   /* Georgian */
+      26,
+      "\341\202\240\341\203\200" /* U+10A0 GEORGIAN CAPITAL LETTER AN
+                                  * U+10D0 GEORGIAN LETTER AN
+                                  */
+    },
+    {
+      "hang",                   /* Hangul */
+      28,
+      "\341\204\200\341\204\201"/* U+1100 HANGUL CHOSEONG KIYEOK
+                                 * U+1101 HANGUL CHOSEONG SSANGKIYEOK
+                                 */
+    },
+    {
+      "ethi",                   /* Ethiopic */
+      75,
+      "\341\210\200"            /* U+1200 ETHIOPIC SYLLABLE HA */
+    },
+    {
+      "cher",                   /* Cherokee */
+      76,
+      "\341\216\243"            /* U+13A3 CHEROKEE LETTER O */
+    },
+    {
+      "cans",                   /* Unified Canadian Aboriginal Syllabics */
+      77,
+      "\341\220\201"            /* U+1401 CANADIAN SYLLABICS E */
+    },
+    {
+      "ogam",                   /* Ogham */
+      78,
+      "\341\232\201"            /* U+1681 OGHAM LETTER BEITH */
+    },
+    {
+      "runr",                   /* Runic */
+      79,
+      "\341\232\240"            /* U+16A0 RUNIC LETTER FEHU FEOH FE F */
+    },
+    {
+      "tglg",                   /* Tagalog */
+      84,
+      "\341\234\200"            /* U+1700 TAGALOG LETTER A */
+    },
+    {
+      "hano",                   /* Hanunoo */
+      -1,
+      "\341\234\240"            /* U+1720 HANUNOO LETTER A */
+    },
+    {
+      "buhd",                   /* Buhid */
+      -1,
+      "\341\235\200"            /* U+1740 BUHID LETTER A */
+    },
+    {
+      "tagb",                   /* Tagbanwa */
+      -1,
+      "\341\235\240"            /* U+1760 TAGBANWA LETTER A */
+    },
+    {
+      "khmr",                   /* Khmer */
+      80,
+      "\341\236\201\341\237\222\341\236\211\341\236\273\341\237\206"
+                                /* U+1781 KHMER LETTER KHA
+                                 * U+17D2 KHMER LETTER SIGN COENG
+                                 * U+1789 KHMER LETTER NYO
+                                 * U+17BB KHMER VOWEL SIGN U
+                                 * U+17C6 KHMER SIGN NIKAHIT
+                                 * A common word meaning "I" that contains
+                                 * lots of complex processing.
+                                 */
+    },
+    {
+      "mong",                   /* Mongolian */
+      81,
+      "\341\240\240"            /* U+1820 MONGOLIAN LETTER A */
+    },
+    {
+      "limb",                   /* Limbu */
+      -1,
+      "\341\244\201"            /* U+1901 LIMBU LETTER KA */
+    },
+    {
+      "tale",                   /* Tai Le */
+      -1,
+      "\341\245\220"            /* U+1950 TAI LE LETTER KA */
+    },
+    {
+      "latn",                   /* Latin */
+      0,
+      "Aa"
+    }
+  };
+
+  gint ot_alts[4];
+  gint n_ot_alts = 0;
+  gint sr_alts[20];
+  gint n_sr_alts = 0;
+
+  font = pango_context_load_font (context, font_desc);
+
+  g_return_val_if_fail (PANGO_IS_FC_FONT (font), "Aa");
+
+  face = pango_fc_font_lock_face (PANGO_FC_FONT (font));
+  g_return_val_if_fail (face != NULL, "Aa");
+  hb_face = hb_ft_face_create (face, NULL);
+
+  /* First check what script(s), if any, the font has GSUB or GPOS
+   * OpenType layout tables for.
+   */
+  for (tt = PANGO_OT_TABLE_GSUB;
+       n_ot_alts < G_N_ELEMENTS (ot_alts) && tt <= PANGO_OT_TABLE_GPOS;
+       tt++)
+    {
+      hb_tag_t tag;
+      unsigned int count;
+      PangoOTTag *slist;
+
+      tag = get_hb_table_type (tt);
+      count = hb_ot_layout_table_get_script_tags (hb_face, tag, 0, NULL, NULL);
+      slist = g_new (PangoOTTag, count + 1);
+      hb_ot_layout_table_get_script_tags (hb_face, tag, 0, &count, slist);
+      slist[count] = 0;
+
+      for (i = 0;
+           n_ot_alts < G_N_ELEMENTS (ot_alts) && i < G_N_ELEMENTS (scripts);
+           i++)
+        {
+          gint j, k;
+
+          for (k = 0; k < n_ot_alts; k++)
+            if (ot_alts[k] == i)
+              break;
+
+          if (k == n_ot_alts)
+            {
+              for (j = 0;
+                   n_ot_alts < G_N_ELEMENTS (ot_alts) && slist[j];
+                   j++)
+                {
+#define TAG(s) FT_MAKE_TAG (s[0], s[1], s[2], s[3])
+
+                  if (slist[j] == TAG (scripts[i].script) &&
+                      gimp_font_covers_string (PANGO_FC_FONT (font),
+                                               scripts[i].sample))
+                    {
+                      ot_alts[n_ot_alts++] = i;
+                      DEBUGPRINT (("%.4s ", scripts[i].script));
+                    }
+#undef TAG
+                }
+            }
+        }
+
+      g_free (slist);
+    }
+
+  hb_face_destroy (hb_face);
+
+  DEBUGPRINT (("; OS/2: "));
+
+  /* Next check the OS/2 table for Unicode ranges the font claims
+   * to cover.
+   */
+
+  os2 = FT_Get_Sfnt_Table (face, ft_sfnt_os2);
+
+  if (os2)
+    {
+      for (i = 0;
+           n_sr_alts < G_N_ELEMENTS (sr_alts) && i < G_N_ELEMENTS (scripts);
+           i++)
+        {
+          if (scripts[i].bit >= 0 &&
+              (&os2->ulUnicodeRange1)[scripts[i].bit/32] & (1 << (scripts[i].bit % 32)) &&
+              gimp_font_covers_string (PANGO_FC_FONT (font),
+                                       scripts[i].sample))
+            {
+              sr_alts[n_sr_alts++] = i;
+              DEBUGPRINT (("%.4s ", scripts[i].script));
+            }
+        }
+    }
+
+  pango_fc_font_unlock_face (PANGO_FC_FONT (font));
+
+  g_object_unref (font);
+
+  if (n_ot_alts > 2)
+    {
+      /* The font has OpenType tables for several scripts. If it
+       * support Basic Latin as well, use Aa.
+       */
+      gint i;
+
+      for (i = 0; i < n_sr_alts; i++)
+        if (scripts[sr_alts[i]].bit == 0)
+          {
+            DEBUGPRINT (("=> several OT, also latin, use Aa\n"));
+            return "Aa";
+          }
+    }
+
+  if (n_ot_alts > 0 && n_sr_alts >= n_ot_alts + 3)
+    {
+      /* At least one script with an OpenType table, but many more
+       * subranges than such scripts. If it supports Basic Latin,
+       * use Aa, else the highest priority subrange.
+       */
+      gint i;
+
+      for (i = 0; i < n_sr_alts; i++)
+        if (scripts[sr_alts[i]].bit == 0)
+          {
+            DEBUGPRINT (("=> several SR, also latin, use Aa\n"));
+            return "Aa";
+          }
+
+      DEBUGPRINT (("=> several SR, use %.4s\n", scripts[sr_alts[0]].script));
+      return scripts[sr_alts[0]].sample;
+    }
+
+  if (n_ot_alts > 0)
+    {
+      /* OpenType tables for at least one script, use the
+       * highest priority one
+       */
+      DEBUGPRINT (("=> at least one OT, use %.4s\n",
+                   scripts[sr_alts[0]].script));
+      return scripts[ot_alts[0]].sample;
+    }
+
+  if (n_sr_alts > 0)
+    {
+      /* Use the highest priority subrange.  This means that a
+       * font that supports Greek, Cyrillic and Latin (quite
+       * common), will get the Greek sample string. That is
+       * capital and lowercase alpha, which looks like capital A
+       * and lowercase alpha, so it's actually quite nice, and
+       * doesn't give a too strong impression that the font would
+       * be for Greek only.
+       */
+      DEBUGPRINT (("=> at least one SR, use %.4s\n",
+                   scripts[sr_alts[0]].script));
+     return scripts[sr_alts[0]].sample;
+    }
+
+  /* Final fallback */
+  DEBUGPRINT (("=> fallback, use Aa\n"));
+  return "Aa";
+}