[pango/pango2-windows] pangodwrite-fontmap: Add property for whether GDI will be used

[Chun-wei Fan <fanchunwei src gnome org>]

commit 673b0f0279f30b44863badeaaecbd30cba53d44e
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Fri Jul 1 19:15:42 2022 +0800

    pangodwrite-fontmap: Add property for whether GDI will be used
    
    ...to create font maps, instead of DirectWrite.  This is so that we can use
    GDI interop in the DirectWrite code to use the classic HFONTS/LOGFONTS to
    create our hb_face's, so that we can use them to work with GDI-based libraries
    and apps that do not have custom renderers to handle the DirectWrite fonts.

 pango2/pangodwrite-fontmap.cpp | 108 +++++++++++++++++++++++++++++++++++++++++
 pango2/pangodwrite-fontmap.h   |   9 +++-
 2 files changed, 116 insertions(+), 1 deletion(-)
---
diff --git a/pango2/pangodwrite-fontmap.cpp b/pango2/pangodwrite-fontmap.cpp
index 7f4ead157..b381dd3ec 100644
--- a/pango2/pangodwrite-fontmap.cpp
+++ b/pango2/pangodwrite-fontmap.cpp
@@ -56,6 +56,7 @@ struct _Pango2DirectWriteFontMap
   Pango2FontMap parent_instance;
 
   IDWriteFactory *dwrite_factory;
+  gboolean use_gdi;
 };
 
 struct _Pango2DirectWriteFontMapClass
@@ -338,6 +339,13 @@ pango2_direct_write_font_map_populate (Pango2FontMap *map)
 /* }}} */
 /* {{{ Pango2DirectWriteFontMap implementation */
 
+enum {
+  PROP_USE_GDI = 1,
+  N_PROPERTIES
+};
+
+static GParamSpec *properties[N_PROPERTIES] = { NULL, };
+
 G_DEFINE_FINAL_TYPE (Pango2DirectWriteFontMap, pango2_direct_write_font_map, PANGO2_TYPE_FONT_MAP)
 
 static void
@@ -366,15 +374,70 @@ pango2_direct_write_font_map_finalize (GObject *object)
   G_OBJECT_CLASS (pango2_direct_write_font_map_parent_class)->finalize (object);
 }
 
+static void
+pango2_direct_write_font_map_set_property (GObject      *object,
+                                           guint         property_id,
+                                           const GValue *value,
+                                           GParamSpec   *pspec)
+{
+  Pango2FontMap *map = PANGO2_FONT_MAP (object);
+
+  switch (property_id)
+    {
+    case PROP_USE_GDI:
+      pango2_direct_write_font_map_set_use_gdi (map, g_value_get_boolean (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+    }
+}
+
+static void
+pango2_direct_write_font_map_get_property (GObject    *object,
+                                           guint       property_id,
+                                           GValue     *value,
+                                           GParamSpec *pspec)
+{
+  Pango2FontMap *map = PANGO2_FONT_MAP (object);
+
+  switch (property_id)
+    {
+    case PROP_USE_GDI:
+      g_value_set_boolean (value, pango2_direct_write_font_map_get_use_gdi (map));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
+    }
+}
+
 static void
 pango2_direct_write_font_map_class_init (Pango2DirectWriteFontMapClass *class_)
 {
   GObjectClass *object_class = G_OBJECT_CLASS (class_);
   Pango2FontMapClass *font_map_class = PANGO2_FONT_MAP_CLASS (class_);
 
+  object_class->set_property = pango2_direct_write_font_map_set_property;
+  object_class->get_property = pango2_direct_write_font_map_get_property;
   object_class->finalize = pango2_direct_write_font_map_finalize;
 
   font_map_class->populate = pango2_direct_write_font_map_populate;
+
+  /**
+   * Pango2DirectWriteFontMap:use-gdi: (attributes 
org.gtk.Property.get=pango2_direct_write_font_map_get_use_gdi 
org.gtk.Property.set=pango2_direct_write_font_map_set_use_gdi)
+   *
+   * Determines whether this context should create GDI LOGFONT-based font maps
+   * instead of DirectWrite ones.
+   *
+   * This is useful when the custom GDI renderer for the DirectWrite fonts is not
+   * ready for the application and the application has not migrated to Direct2D.
+   */
+  properties[PROP_USE_GDI] =
+    g_param_spec_boolean ("use-gdi", NULL, NULL, FALSE,
+                          (GParamFlags)(G_PARAM_READWRITE | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_properties (object_class, N_PROPERTIES, properties);
 }
 
 /* }}} */
@@ -393,6 +456,51 @@ pango2_direct_write_font_map_new (void)
   return (Pango2DirectWriteFontMap *) g_object_new (PANGO2_TYPE_DIRECT_WRITE_FONT_MAP, NULL);
 }
 
+/**
+ * pango2_direct_write_set_use_gdi:
+ * @map: a `Pango2FontMap`
+ * @use_gdi: whether to use GDI
+ *
+ * Sets whether this font map should use GDI-based font maps
+ * instead of the normal DirectWrite-based font maps.
+ *
+ * This is useful when the custom renderer for DirectWrite fonts
+ * for GDI is not ready and Direct2D is not used for the application
+ * or library.
+ *
+ * The default value is to use DirectWrite-based font maps.
+ */
+void
+pango2_direct_write_font_map_set_use_gdi (Pango2FontMap *map,
+                                          gboolean       use_gdi)
+{
+  Pango2DirectWriteFontMap *dwrite_map;
+
+  g_return_if_fail (PANGO2_IS_DIRECT_WRITE_FONT_MAP (map));
+
+  dwrite_map = PANGO2_DIRECT_WRITE_FONT_MAP (map);
+
+  if (dwrite_map->use_gdi == use_gdi)
+    return;
+
+  dwrite_map->use_gdi = use_gdi;
+  g_object_notify_by_pspec (G_OBJECT (dwrite_map), properties[PROP_USE_GDI]);
+}
+
+/**
+ * pango2_direct_write_get_use_gdi:
+ * @map: a `Pango2FontMap`
+ *
+ * Returns whether GDI-based font maps are used with this FontMap.
+ */
+gboolean
+pango2_direct_write_font_map_get_use_gdi (Pango2FontMap *map)
+{
+  g_return_val_if_fail (PANGO2_IS_DIRECT_WRITE_FONT_MAP (map), FALSE);
+
+  return PANGO2_DIRECT_WRITE_FONT_MAP (map)->use_gdi;
+}
+
 /* }}} */
 
 /* vim:set foldmethod=marker expandtab: */
diff --git a/pango2/pangodwrite-fontmap.h b/pango2/pangodwrite-fontmap.h
index c873759da..2f13d18d5 100644
--- a/pango2/pangodwrite-fontmap.h
+++ b/pango2/pangodwrite-fontmap.h
@@ -34,7 +34,14 @@ PANGO2_DECLARE_INTERNAL_TYPE (Pango2DirectWriteFontMap,
                               Pango2FontMap)
 
 PANGO2_AVAILABLE_IN_ALL
-Pango2DirectWriteFontMap * pango2_direct_write_font_map_new (void);
+Pango2DirectWriteFontMap *pango2_direct_write_font_map_new         (void);
+
+PANGO2_AVAILABLE_IN_ALL
+void                      pango2_direct_write_font_map_set_use_gdi (Pango2FontMap *map,
+                                                                    gboolean       use_gdi);
+
+PANGO2_AVAILABLE_IN_ALL
+gboolean                  pango2_direct_write_font_map_get_use_gdi (Pango2FontMap *map);
 
 
 G_END_DECLS