[gucharmap] charmap: Enhance the font name combo box by an entry with completion

[Christian Persch <chpe src gnome org>]

commit 5e4c982a1afb6fcdc1f59b01a6fa55c50a6b3ad1
Author: Dov Grobgeld <dov grobgeld gmail com>
Date:   Mon Jul 30 12:51:56 2018 +0200

    charmap: Enhance the font name combo box by an entry with completion
    
    The font name entry combo box has been enhanced with an entry
    widget that does partial font name completion. This makes
    searching for a font much faster when a large number of fonts
    are installed.
    
    https://gitlab.gnome.org/GNOME/gucharmap/issues/7

 gucharmap/gucharmap-mini-fontsel.c | 82 ++++++++++++++++++++++++++++++++------
 gucharmap/gucharmap-mini-fontsel.h |  1 +
 2 files changed, 70 insertions(+), 13 deletions(-)
---
diff --git a/gucharmap/gucharmap-mini-fontsel.c b/gucharmap/gucharmap-mini-fontsel.c
index 746153fa..fe8a8a27 100644
--- a/gucharmap/gucharmap-mini-fontsel.c
+++ b/gucharmap/gucharmap-mini-fontsel.c
@@ -55,12 +55,9 @@ G_DEFINE_TYPE (GucharmapMiniFontSelection, gucharmap_mini_font_selection, GTK_TY
 static void
 fill_font_families_combo (GucharmapMiniFontSelection *fontsel)
 {
-  GtkComboBox *combo = GTK_COMBO_BOX (fontsel->family);
   PangoFontFamily **families;
   int n_families, i;
 
-  fontsel->family_store = gtk_list_store_new (1, G_TYPE_STRING);
-
   pango_context_list_families (
           gtk_widget_get_pango_context (GTK_WIDGET (fontsel)),
           &families, &n_families);
@@ -83,9 +80,6 @@ fill_font_families_combo (GucharmapMiniFontSelection *fontsel)
   gtk_tree_sortable_set_sort_column_id (GTK_TREE_SORTABLE (fontsel->family_store),
                                         COL_FAMILIY,
                                         GTK_SORT_ASCENDING);
-
-  gtk_combo_box_set_model (combo, GTK_TREE_MODEL (fontsel->family_store));
-  g_object_unref (fontsel->family_store);
 }
 
 static void
@@ -143,6 +137,63 @@ family_combo_changed (GtkComboBox *combo,
   g_object_notify (G_OBJECT (fontsel), "font-desc");
 }
 
+static gboolean
+match_function (GtkEntryCompletion *completion,
+                const gchar *key,
+                GtkTreeIter *iter,
+                gpointer user_data)
+{
+  GucharmapMiniFontSelection *fontsel = GUCHARMAP_MINI_FONT_SELECTION (user_data);
+  char *family, *family_fold;
+  gchar **sub_match, **p;
+  gboolean all_matches = TRUE;
+
+  gtk_tree_model_get (GTK_TREE_MODEL (fontsel->family_store),
+                      iter,
+                      COL_FAMILIY, &family,
+                      -1);
+  family_fold = g_utf8_casefold (family, -1);
+
+  /* Match if all space separated substrings are part of family string */
+  sub_match = g_strsplit (key, " ", -1);
+  p = sub_match;
+  while (*p) {
+      gchar *match_fold = g_utf8_casefold (*p++, -1);
+      if (!g_strstr_len (family_fold, -1, match_fold))
+          all_matches = FALSE;
+      g_free (match_fold);
+      if (!all_matches)
+          break;
+  }
+
+  g_free (family);
+  g_free (family_fold);
+  g_strfreev (sub_match);
+
+  return all_matches;
+}
+
+static gboolean
+completion_match_selected(GtkEntryCompletion *widget,
+                          GtkTreeModel       *model,
+                          GtkTreeIter        *iter,
+                          GucharmapMiniFontSelection *fontsel)
+{
+  char *family;
+
+  gtk_tree_model_get (GTK_TREE_MODEL (fontsel->family_store),
+                      iter,
+                      COL_FAMILIY, &family,
+                      -1);
+  pango_font_description_set_family (fontsel->font_desc, family);
+  g_free (family);
+
+  g_object_notify (G_OBJECT (fontsel), "font-desc");
+
+  return FALSE;
+}
+
+
 /* returns font size in points */
 static int
 get_font_size (GucharmapMiniFontSelection *fontsel)
@@ -266,7 +317,6 @@ italic_toggled (GtkToggleButton *toggle,
 static void
 gucharmap_mini_font_selection_init (GucharmapMiniFontSelection *fontsel)
 {
-  GtkCellRenderer *renderer;
   GtkStyle *style;
   AtkObject *accessib;
 
@@ -283,13 +333,19 @@ gucharmap_mini_font_selection_init (GucharmapMiniFontSelection *fontsel)
 
   gtk_box_set_spacing (GTK_BOX (fontsel), 6);
 
-  fontsel->family = gtk_combo_box_new ();
+  fontsel->family_store = gtk_list_store_new (1, G_TYPE_STRING);
 
-  renderer = gtk_cell_renderer_text_new ();
-  gtk_cell_layout_pack_start (GTK_CELL_LAYOUT (fontsel->family), renderer, TRUE);
-  gtk_cell_layout_set_attributes (GTK_CELL_LAYOUT (fontsel->family), renderer,
-                                  "text", COL_FAMILIY,
-                                  NULL);
+  fontsel->family = gtk_combo_box_new_with_model_and_entry (GTK_TREE_MODEL (fontsel->family_store));
+  gtk_combo_box_set_entry_text_column (GTK_COMBO_BOX(fontsel->family), COL_FAMILIY);
+  fontsel->completion = gtk_entry_completion_new();
+  gtk_entry_completion_set_text_column (fontsel->completion, COL_FAMILIY);
+  gtk_entry_completion_set_model (fontsel->completion, GTK_TREE_MODEL (fontsel->family_store));
+  gtk_entry_completion_set_match_func(fontsel->completion, match_function, fontsel, NULL);
+  g_signal_connect (G_OBJECT (fontsel->completion), "match-selected",
+                    G_CALLBACK (completion_match_selected), fontsel);
+
+  gtk_entry_set_completion (GTK_ENTRY (gtk_bin_get_child (GTK_BIN (fontsel->family))),
+                            fontsel->completion);
   gtk_widget_show (fontsel->family);
   accessib = gtk_widget_get_accessible (fontsel->family);
   atk_object_set_name (accessib, _("Font Family"));
diff --git a/gucharmap/gucharmap-mini-fontsel.h b/gucharmap/gucharmap-mini-fontsel.h
index e075ad69..a1f990f1 100644
--- a/gucharmap/gucharmap-mini-fontsel.h
+++ b/gucharmap/gucharmap-mini-fontsel.h
@@ -39,6 +39,7 @@ struct _GucharmapMiniFontSelection
   GtkHBox parent;
 
   GtkListStore         *family_store;
+  GtkEntryCompletion   *completion; /* font name completion */
   GtkWidget            *family; /* combo box */
   GtkWidget            *bold;   /* toggle button*/
   GtkWidget            *italic; /* toggle button*/