Add PangoHbFamily

This is a straightforward implementation of
PangoFontFamily for use with PangoHbFace.

3 files changed, 449 insertions, 0 deletions

diff --git a/pango/meson.build b/pango/meson.build
index c12aa1bf..2b42c944 100644
--- a/pango/meson.build
+++ b/pango/meson.build
@@ -35,6 +35,7 @@ pango_sources = [
   'json/gtkjsonparser.c',
   'json/gtkjsonprinter.c',
   'pango-hbface.c',
+  'pango-hbfamily.c',
 ]
 
 pango_headers = [
diff --git a/pango/pango-hbfamily-private.h b/pango/pango-hbfamily-private.h
new file mode 100644
index 00000000..7b1dfa9a
--- /dev/null
+++ b/pango/pango-hbfamily-private.h
@@ -0,0 +1,55 @@
+/* Pango
+ *
+ * Copyright (C) 2021 Matthias Clasen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#pragma once
+
+#include "pango-font.h"
+#include "pango-hbface.h"
+
+#define PANGO_TYPE_HB_FAMILY (pango_hb_family_get_type ())
+
+PANGO_AVAILABLE_IN_1_52
+G_DECLARE_FINAL_TYPE (PangoHbFamily, pango_hb_family, PANGO, HB_FAMILY, PangoFontFamily)
+
+struct _PangoHbFamily
+{
+  PangoFontFamily parent_instance;
+
+  PangoFontMap *map;
+  char *name;
+  GPtrArray *faces;
+};
+
+PANGO_AVAILABLE_IN_1_52
+PangoHbFamily *         pango_hb_family_new             (const char             *name);
+
+void                    pango_hb_family_set_font_map    (PangoHbFamily          *self,
+                                                         PangoFontMap           *map);
+
+void                    pango_hb_family_add_face        (PangoHbFamily          *self,
+                                                         PangoHbFace            *face);
+
+void                    pango_hb_family_remove_face     (PangoHbFamily          *self,
+                                                         PangoHbFace            *face);
+
+PangoHbFace *           pango_hb_family_find_face       (PangoHbFamily          *self,
+                                                         PangoFontDescription   *description,
+                                                         PangoLanguage          *language,
+                                                         gunichar                wc);
diff --git a/pango/pango-hbfamily.c b/pango/pango-hbfamily.c
new file mode 100644
index 00000000..814ec5f8
--- /dev/null
+++ b/pango/pango-hbfamily.c
@@ -0,0 +1,393 @@
+/* Pango
+ *
+ * Copyright (C) 2021 Matthias Clasen
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Library General Public
+ * License as published by the Free Software Foundation; either
+ * version 2 of the License, or (at your option) any later version.
+ *
+ * This library 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
+ * Library General Public License for more details.
+ *
+ * You should have received a copy of the GNU Library General Public
+ * License along with this library; if not, write to the
+ * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
+ * Boston, MA 02111-1307, USA.
+ */
+
+#include "config.h"
+
+#include <gio/gio.h>
+
+#include "pango-hbfamily-private.h"
+#include "pango-impl-utils.h"
+#include "pango-hbface-private.h"
+#include "pango-font-private.h"
+
+/* {{{ GListModel implementation */
+
+static GType
+pango_hb_family_get_item_type (GListModel *list)
+{
+  return PANGO_TYPE_FONT_FACE;
+}
+
+static guint
+pango_hb_family_get_n_items (GListModel *list)
+{
+  PangoHbFamily *self = PANGO_HB_FAMILY (list);
+
+  return self->faces->len;
+}
+
+static gpointer
+pango_hb_family_get_item (GListModel *list,
+                              guint       position)
+{
+  PangoHbFamily *self = PANGO_HB_FAMILY (list);
+
+  if (position < self->faces->len)
+    return g_object_ref (g_ptr_array_index (self->faces, position));
+
+  return NULL;
+}
+
+static void
+pango_hb_family_list_model_init (GListModelInterface *iface)
+{
+  iface->get_item_type = pango_hb_family_get_item_type;
+  iface->get_n_items = pango_hb_family_get_n_items;
+  iface->get_item = pango_hb_family_get_item;
+}
+
+/* }}} */
+/* {{{ Utilities */
+
+static int
+sort_face_func (PangoHbFace *face1,
+                PangoHbFace *face2)
+{
+  int a, b;
+
+  a = pango_font_description_get_style (face1->description);
+  b = pango_font_description_get_style (face2->description);
+  if (a != b)
+    return a - b;
+
+  a = pango_font_description_get_weight (face1->description);
+  b = pango_font_description_get_weight (face2->description);
+  if (a != b)
+    return a - b;
+
+  a = pango_font_description_get_stretch (face1->description);
+  b = pango_font_description_get_stretch (face2->description);
+  if (a != b)
+    return a - b;
+
+  return strcmp (face1->name, face2->name);
+}
+
+/* return 2 if face is a named instance,
+ * 1 if it is variable
+ * 0 otherwise
+ */
+static int
+hb_face_get_variableness (PangoHbFace *face)
+{
+  if (pango_font_face_is_variable (PANGO_FONT_FACE (face)))
+    {
+      if (face->instance_id != -1)
+        return 2;
+      else
+        return 1;
+    }
+ return 0;
+}
+
+/* }}} */
+/* {{{ PangoFontFamily implementation */
+
+struct _PangoHbFamilyClass
+{
+  PangoFontFamilyClass parent_class;
+};
+
+G_DEFINE_TYPE_WITH_CODE (PangoHbFamily, pango_hb_family, PANGO_TYPE_FONT_FAMILY,
+                         G_IMPLEMENT_INTERFACE (G_TYPE_LIST_MODEL, pango_hb_family_list_model_init))
+
+static void
+pango_hb_family_init (PangoHbFamily *self)
+{
+  self->faces = g_ptr_array_new_with_free_func (g_object_unref);
+}
+
+static void
+pango_hb_family_finalize (GObject *object)
+{
+  PangoHbFamily *self = PANGO_HB_FAMILY (object);
+
+  g_free (self->name);
+  g_ptr_array_unref (self->faces);
+
+  G_OBJECT_CLASS (pango_hb_family_parent_class)->finalize (object);
+}
+
+static const char *
+pango_hb_family_get_name (PangoFontFamily *family)
+{
+  PangoHbFamily *self = PANGO_HB_FAMILY (family);
+
+  return self->name;
+}
+
+static void
+pango_hb_family_list_faces (PangoFontFamily   *family,
+                            PangoFontFace   ***faces,
+                            int               *n_faces)
+{
+  PangoHbFamily *self = PANGO_HB_FAMILY (family);
+
+  if (faces)
+    *faces = g_memdup2 (self->faces->pdata, self->faces->len * sizeof (PangoFontFace *));
+
+  if (n_faces)
+    *n_faces = self->faces->len;
+}
+
+static PangoFontFace *
+pango_hb_family_get_face (PangoFontFamily *family,
+                          const char      *name)
+{
+  PangoHbFamily *self = PANGO_HB_FAMILY (family);
+
+  for (int i = 0; i < self->faces->len; i++)
+    {
+      PangoFontFace *face = g_ptr_array_index (self->faces, i);
+
+      if (name == NULL || strcmp (name, pango_font_face_get_face_name (face)) == 0)
+        return face;
+    }
+
+  return NULL;
+}
+
+static gboolean
+pango_hb_family_is_monospace (PangoFontFamily *family)
+{
+  PangoHbFamily *self = PANGO_HB_FAMILY (family);
+
+  for (int i = 0; i < self->faces->len; i++)
+    {
+      PangoFontFace *face = g_ptr_array_index (self->faces, i);
+
+      if (pango_font_face_is_monospace (face))
+        return TRUE;
+    }
+
+  return FALSE;
+}
+
+static gboolean
+pango_hb_family_is_variable (PangoFontFamily *family)
+{
+  PangoHbFamily *self = PANGO_HB_FAMILY (family);
+
+  for (int i = 0; i < self->faces->len; i++)
+    {
+      PangoFontFace *face = g_ptr_array_index (self->faces, i);
+
+      if (pango_font_face_is_variable (face))
+        return TRUE;
+    }
+
+  return FALSE;
+}
+
+static void
+pango_hb_family_class_init (PangoHbFamilyClass *class)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (class);
+  PangoFontFamilyClass *family_class = PANGO_FONT_FAMILY_CLASS (class);
+
+  object_class->finalize = pango_hb_family_finalize;
+
+  family_class->list_faces = pango_hb_family_list_faces;
+  family_class->get_name = pango_hb_family_get_name;
+  family_class->get_face = pango_hb_family_get_face;
+  family_class->is_monospace = pango_hb_family_is_monospace;
+  family_class->is_variable = pango_hb_family_is_variable;
+}
+
+/* }}} */
+/* {{{ Private API */
+
+/*< private >
+ * pango_hb_family_new:
+ * @name: the family name
+ *
+ * Creates a new `PangoHbFamily`.
+ *
+ * Returns: a newly created `PangoHbFamily`
+ */
+PangoHbFamily *
+pango_hb_family_new (const char *name)
+{
+  PangoHbFamily *self;
+
+  self = g_object_new (PANGO_TYPE_HB_FAMILY, NULL);
+
+  self->name = g_strdup (name);
+
+  return self;
+}
+
+/*< private >
+ * pango_hb_family_set_font_map:
+ * @self: a `PangoHbFamily`
+ * @map: (nullable): a `PangoFontMap`
+ *
+ * Sets the map of @self.
+ */
+void
+pango_hb_family_set_font_map (PangoHbFamily *self,
+                              PangoFontMap  *map)
+{
+  if (self->map)
+    g_object_remove_weak_pointer (G_OBJECT (self->map), (gpointer *)&self->map);
+
+  self->map = map;
+
+  if (self->map)
+    g_object_add_weak_pointer (G_OBJECT (self->map), (gpointer *)&self->map);
+}
+
+/*< private >
+ * pango_hb_family_add_face:
+ * @self: a `PangoHbFamily`
+ * @face: (transfer full): a `PangoFontFace` to add
+ *
+ * Adds a `PangoFontFace` to a `PangoHbFamily`.
+ *
+ * The family takes ownership of the added face.
+ *
+ * It is an error to call this function more than
+ * once for the same face.
+ */
+void
+pango_hb_family_add_face (PangoHbFamily *self,
+                          PangoHbFace   *face)
+{
+  int position;
+
+  position = 0;
+  while (position < self->faces->len)
+    {
+      PangoHbFace *f = g_ptr_array_index (self->faces, position);
+      if (sort_face_func (face, f) < 0)
+        break;
+      position++;
+    }
+
+  g_ptr_array_insert (self->faces, position, face);
+  pango_hb_face_set_family (face, PANGO_FONT_FAMILY (self));
+
+  g_list_model_items_changed (G_LIST_MODEL (self), position, 0, 1);
+}
+
+/*< private >
+ * pango_hb_family_remove_face:
+ * @self: a `PangoHbFamily`
+ * @face: a `PangoHbFace`
+ *
+ * Remove a `PangoFontFace` from a `PangoHbFamily`.
+ */
+void
+pango_hb_family_remove_face (PangoHbFamily *self,
+                             PangoHbFace   *face)
+{
+  unsigned int position;
+
+  if (!g_ptr_array_find (self->faces, face, &position))
+    return;
+
+  pango_hb_face_set_family (face, NULL);
+  g_ptr_array_remove_index (self->faces, position);
+
+  g_list_model_items_changed (G_LIST_MODEL (self), position, 1, 0);
+}
+
+/*< private >
+ * pango_hb_family_find_face:
+ * @family: a `PangoHbFamily`
+ * @description: `PangoFontDescription` to match
+ * @language: (nullable): `PangoLanguage` to support
+ * @wc: a Unicode character, or 0 to ignore
+ *
+ * Finds the face in @family that best matches the font description while
+ * also supporting the given language and character.
+ *
+ * Amongst equally matching faces, a variable face is preferred over a
+ * non-variable one, and a named instance is preferred over a bare variable
+ * face.
+ *
+ * Returns: (transfer none) (nullable): the face
+ */
+PangoHbFace *
+pango_hb_family_find_face (PangoHbFamily        *family,
+                           PangoFontDescription *description,
+                           PangoLanguage        *language,
+                           gunichar              wc)
+{
+  PangoHbFace *face = NULL;
+  int best_distance = G_MAXINT;
+  int best_variableness = 0;
+
+  /* First look for an exact match if the description has a faceid */
+  if (pango_font_description_get_set_fields (description) & PANGO_FONT_MASK_FACEID)
+    {
+      for (int i = 0; i < family->faces->len; i++)
+        {
+          PangoHbFace *face2 = g_ptr_array_index (family->faces, i);
+
+          if (g_strcmp0 (pango_font_description_get_faceid (description),
+                         pango_hb_face_get_faceid (face2)) == 0)
+            return face2;
+        }
+    }
+
+  for (int i = 0; i < family->faces->len; i++)
+    {
+      PangoHbFace *face2 = g_ptr_array_index (family->faces, i);
+      int distance;
+      int variableness;
+
+      if (language && !pango_font_face_supports_language (PANGO_FONT_FACE (face2), language))
+        continue;
+
+      if (wc && !pango_hb_face_has_char (face2, wc))
+        continue;
+
+      if (!pango_font_description_is_similar (description, face2->description))
+        continue;
+
+      distance = pango_font_description_compute_distance (description, face2->description);
+
+      variableness = hb_face_get_variableness (face2);
+      if (distance < best_distance ||
+          (distance == best_distance && variableness > best_variableness))
+        {
+          face = face2;
+          best_distance = distance;
+          best_variableness = variableness;
+        }
+    }
+
+  return face;
+}
+
+/* }}} */
+
+/* vim:set foldmethod=marker expandtab: */