[gtk/wip/fanc999/fontchooser.win32.gtk3] [WIP] gtk/gtkfontfeatures.c: Add support for PangoWin32Font->FT_Face

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

commit 5ce7e1c05b1228ee982ec1bc51d6a672e2b3269b
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Wed Dec 26 18:21:02 2018 +0800

    [WIP] gtk/gtkfontfeatures.c: Add support for PangoWin32Font->FT_Face
    
    ...WIP!!!...
    
    This is so that we can turn the LOGFONT that is retrieved from the
    PangoFont so that we can load it with FreeType and feed it to HarfBuzz.
    
    There is ongoing work in Pango to do shaping on all supported platforms
    using HarfBuzz, but since this is GTK+-3.24.x, we will still need to
    support the code path without it as well.

 gtk/gtkfontchooserwidget.c   |   6 +-
 gtk/gtkfontfeatures.c        | 182 +++++++++++++++++++++++++++++++++++++++++--
 gtk/gtkfontfeaturesprivate.h |   2 +
 3 files changed, 179 insertions(+), 11 deletions(-)
---
diff --git a/gtk/gtkfontchooserwidget.c b/gtk/gtkfontchooserwidget.c
index 20d6380af9..bc542fca55 100644
--- a/gtk/gtkfontchooserwidget.c
+++ b/gtk/gtkfontchooserwidget.c
@@ -713,7 +713,7 @@ gtk_font_chooser_widget_init (GtkFontChooserWidget *fontchooser)
 
   gtk_widget_init_template (GTK_WIDGET (fontchooser));
 
-#if defined(HAVE_HARFBUZZ) && defined (HAVE_PANGOFT)
+#ifdef HAVE_HARFBUZZ
   priv->axes = g_hash_table_new_full (axis_hash, axis_equal, NULL, axis_free);
 #endif
 
@@ -754,7 +754,7 @@ gtk_font_chooser_widget_init (GtkFontChooserWidget *fontchooser)
 
   /* Load data and set initial style-dependent parameters */
   gtk_font_chooser_widget_load_fonts (fontchooser, TRUE);
-#if defined(HAVE_HARFBUZZ) && defined (HAVE_PANGOFT)
+#ifdef HAVE_HARFBUZZ
   gtk_font_chooser_widget_populate_features (fontchooser);
 #endif
   gtk_font_chooser_widget_set_cell_size (fontchooser);
@@ -1379,7 +1379,7 @@ gtk_font_chooser_widget_merge_font_desc (GtkFontChooserWidget       *fontchooser
 
       gtk_font_chooser_widget_update_marks (fontchooser);
 
-#if defined(HAVE_HARFBUZZ) && defined (HAVE_PANGOFT)
+#ifdef HAVE_HARFBUZZ
       if (gtk_font_chooser_widget_update_font_features (fontchooser))
         has_tweak = TRUE;
       if (gtk_font_chooser_widget_update_font_variations (fontchooser))
diff --git a/gtk/gtkfontfeatures.c b/gtk/gtkfontfeatures.c
index 4133405527..f2da6fff75 100644
--- a/gtk/gtkfontfeatures.c
+++ b/gtk/gtkfontfeatures.c
@@ -33,8 +33,18 @@
 #include "gtkradiobutton.h"
 #include "gtkgesturemultipress.h"
 
-#if defined (HAVE_HARFBUZZ) && defined (HAVE_PANGOFT)
-#include <pango/pangofc-font.h>
+#ifdef HAVE_HARFBUZZ
+
+#ifdef HAVE_PANGOFT
+# include <pango/pangofc-font.h>
+#endif
+#ifdef GDK_WINDOWING_WIN32
+# include <pango/pangowin32.h>
+
+/* Check for TTC fonts and get their font data */
+# define FONT_TABLE_TTCF  (('t' << 0) + ('t' << 8) + ('c' << 16) + ('f' << 24))
+#endif
+
 #include <hb.h>
 #include <hb-ot.h>
 #include <hb-ft.h>
@@ -85,6 +95,150 @@ axis_remove (gpointer key,
   gtk_widget_destroy (a->spin);
 }
 
+/* Until Pango uses HarfBuzz for shaping on all platforms, we need to go through FreeType */
+#ifdef GDK_WINDOWING_WIN32
+
+typedef struct _gtk_win32_ft_items
+{
+  FT_Library ft_lib;
+  FT_Byte *font_data_stream;
+  FT_Face face;
+  HDC hdc;
+  LOGFONTW *logfont;
+  HFONT hfont;
+} gtk_win32_ft_items;
+
+static FT_Face
+get_ftface_from_pangowin32_font (PangoFont                   *font,
+                                 PangoFontMap                *font_map,
+                                 GtkFontChooserWidgetPrivate *priv)
+{
+  PangoWin32FontCache *cache = NULL;
+  LOGFONTW *logfont;
+  HFONT hfont;
+  unsigned char buf[4];
+  HDC hdc;
+  gsize font_size;
+  DWORD is_ttc_font;
+  gtk_win32_ft_items *item = NULL;
+
+  cache = pango_win32_font_map_get_font_cache (font_map);
+
+  if (!cache)
+    {
+      g_warning ("Failed to acquire PangoWin32FontCache, font features will likely not work!");
+      return NULL;
+    }
+
+  logfont = pango_win32_font_logfontw (font);
+  hfont = pango_win32_font_cache_loadw (cache, logfont);
+  hdc = GetDC (NULL);
+
+  if (hdc == NULL)
+    {
+      g_warning ("Failed to acquire DC, font features will likely not work!");
+      return NULL;
+    }
+
+  if (priv->ft_ext_items == NULL)
+    priv->ft_ext_items = g_new0 (gtk_win32_ft_items, 1);
+
+  item = (gtk_win32_ft_items *) priv->ft_ext_items;
+
+  /* We need to track these because we can only release/free those items *after* we
+   * are done with them in FreeType
+   */
+  item->logfont = logfont;
+  item->hfont = hfont;
+  item->hdc = hdc;
+
+  if (item->ft_lib == NULL)
+    {
+      if (FT_Init_FreeType (&item->ft_lib) != FT_Err_Ok)
+        {
+          g_warning ("Failed to initialize FreeType, font features will likely not work!");
+          return NULL;
+        }
+    }
+
+  if (SelectObject (hdc, hfont) == HGDI_ERROR)
+    {
+      g_warning ("SelectObject() for the PangoFont failed, font features will likely not work!");
+      return NULL;
+    }
+
+  item->hfont = hfont;
+
+  /* Check whether the HFONT refers to a font in a .ttc font file */
+  is_ttc_font = GetFontData(hdc, FONT_TABLE_TTCF, 0, &buf, 1);
+
+  if (is_ttc_font == 1)
+    font_size = GetFontData(hdc, FONT_TABLE_TTCF, 0, NULL, 0);
+  else
+    font_size = GetFontData(hdc, 0, 0, NULL, 0);
+
+  if (font_size == GDI_ERROR && is_ttc_font == GDI_ERROR)
+    {
+      g_warning ("GetFontData() failed");
+      return NULL;
+    }
+
+  /* Now, get the font data stream that we need for creating the FT_Face */
+  item->font_data_stream = g_malloc (font_size);
+  if (GetFontData (hdc,
+                   is_ttc_font == 1 ? FONT_TABLE_TTCF : 0,
+                   0,
+                   item->font_data_stream,
+                   font_size) == GDI_ERROR)
+    {
+      /* Todo: Cleanup !*/
+      g_warning ("Unable to get data stream of font!");
+      return NULL;
+    }
+
+  /* Finally, create the FT_Face we need */
+  if (FT_New_Memory_Face (item->ft_lib,
+                          item->font_data_stream,
+                          font_size,
+                          0,
+                          &item->face) != FT_Err_Ok)
+    {
+      /* Todo: Cleanup! */
+      g_warning ("Unable to create FT_Face!");
+      return NULL;
+    }
+
+  /* Todo: Cleanup function */
+  return item->face;
+}
+
+/* Windows: Determine whether we are using PangoWin32 or PangoFT, if there is PangoFT support */
+# ifdef HAVE_PANGOFT
+#  define FT_FACE_FROM_PANGO_FONT(f,m,p) \
+          PANGO_IS_FC_FONT(f) ?        \
+          pango_fc_font_lock_face (PANGO_FC_FONT (f)) : \
+          get_ftface_from_pangowin32_font (f, m, p)
+
+#  define PANGO_FONT_UNLOCK_FACE(f) pango_fc_font_unlock_face(PANGO_FC_FONT(f))
+# else
+#  define FT_FACE_FROM_PANGO_FONT(f,m,p) get_ftface_from_pangowin32_font (f, m, p)
+#  define PANGO_FONT_UNLOCK_FACE(f)
+# endif
+
+/* Non-Windows: Just assume we are using PangoFT */
+#elif defined (HAVE_PANGOFT)
+# define FT_FACE_FROM_PANGO_FONT(f,m,p) pango_fc_font_lock_face (PANGO_FC_FONT (f))
+# define PANGO_FONT_UNLOCK_FACE(f) pango_fc_font_unlock_face(PANGO_FC_FONT(f))
+#endif
+
+static FT_Face
+get_ft_face_from_pango_font (PangoFont                   *font,
+                             PangoFontMap                *font_map,
+                             GtkFontChooserWidgetPrivate *priv)
+{
+  return FT_FACE_FROM_PANGO_FONT (font, font_map, priv);
+}
+
 /* OpenType variations */
 
 #define FixedToFloat(f) (((float)(f))/65536.0)
@@ -241,6 +395,7 @@ gtk_font_chooser_widget_update_font_variations (GtkFontChooserWidget *fontchoose
   FT_MM_Var *ft_mm_var;
   FT_Error ret;
   gboolean has_axis = FALSE;
+  PangoFontMap *font_map = NULL;
 
   if (priv->updating_variations)
     return FALSE;
@@ -254,7 +409,12 @@ gtk_font_chooser_widget_update_font_variations (GtkFontChooserWidget *fontchoose
   pango_font = pango_context_load_font (gtk_widget_get_pango_context (GTK_WIDGET (fontchooser)),
                                         priv->font_desc);
 
-  ft_face = pango_fc_font_lock_face (PANGO_FC_FONT (pango_font));
+  if (priv->font_map != NULL)
+    font_map = priv->font_map;
+  else
+    font_map = pango_cairo_font_map_get_default ();
+
+  ft_face = get_ft_face_from_pango_font (pango_font, font_map, priv);
 
   ret = FT_Get_MM_Var (ft_face, &ft_mm_var);
   if (ret == 0)
@@ -286,7 +446,7 @@ gtk_font_chooser_widget_update_font_variations (GtkFontChooserWidget *fontchoose
       free (ft_mm_var);
     }
 
-  pango_fc_font_unlock_face (PANGO_FC_FONT (pango_font));
+  PANGO_FONT_UNLOCK_FACE (pango_font);
 
   g_object_unref (pango_font);
 
@@ -775,6 +935,7 @@ gtk_font_chooser_widget_update_font_features (GtkFontChooserWidget *fontchooser)
   int i, j;
   GList *l;
   gboolean has_feature = FALSE;
+  PangoFontMap *font_map = NULL;
 
   for (l = priv->feature_items; l; l = l->next)
     {
@@ -782,14 +943,19 @@ gtk_font_chooser_widget_update_font_features (GtkFontChooserWidget *fontchooser)
       gtk_widget_hide (item->top);
       gtk_widget_hide (gtk_widget_get_parent (item->top));
     }
-
+/* *** Re-enable this later ! ***
   if ((priv->level & GTK_FONT_CHOOSER_LEVEL_FEATURES) == 0)
-    return FALSE;
+    return FALSE;*/
 
   pango_font = pango_context_load_font (gtk_widget_get_pango_context (GTK_WIDGET (fontchooser)),
                                         priv->font_desc);
 
-  ft_face = pango_fc_font_lock_face (PANGO_FC_FONT (pango_font));
+  if (priv->font_map != NULL)
+    font_map = priv->font_map;
+  else
+    font_map = pango_cairo_font_map_get_default ();
+
+  ft_face = get_ft_face_from_pango_font (pango_font, font_map, priv);
 
   hb_font = hb_ft_font_create (ft_face, NULL);
 
@@ -850,7 +1016,7 @@ gtk_font_chooser_widget_update_font_features (GtkFontChooserWidget *fontchooser)
       hb_face_destroy (hb_face);
     }
 
-  pango_fc_font_unlock_face (PANGO_FC_FONT (pango_font));
+  PANGO_FONT_UNLOCK_FACE (pango_font);
 
   g_object_unref (pango_font);
 
diff --git a/gtk/gtkfontfeaturesprivate.h b/gtk/gtkfontfeaturesprivate.h
index d24c0ba31b..8e4e848aa2 100644
--- a/gtk/gtkfontfeaturesprivate.h
+++ b/gtk/gtkfontfeaturesprivate.h
@@ -70,6 +70,8 @@ struct _GtkFontChooserWidgetPrivate
   GList *feature_items;
 
   GAction *tweak_action;
+
+  gpointer ft_ext_items;
 };
 
 typedef struct {