[pango/win32-font-language: 5/5] PangoWin32: Initialize DirectWrite as well

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

commit 9bfb8f113aad61249e10972c850cda339d4be655
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Wed Nov 11 20:15:25 2020 +0800

    PangoWin32: Initialize DirectWrite as well
    
    We want to start using DirectWrite to help us implement some features
    that are not that easily done with GDI/Uniscribe, via a GDI interop
    layer as provided by DirectWrite, and by creating and keeping track of
    the IDWriteFont's that are created from each of the LOGFONTs that we
    acquire by quering the fonts that is installed on the system.

 pango/meson.build          |  1 +
 pango/pangowin32-fontmap.c |  9 +++++++++
 pango/pangowin32-private.h |  7 +++++++
 pango/pangowin32.c         | 35 +++++++++++++++++++++++++++++++++++
 4 files changed, 52 insertions(+)
---
diff --git a/pango/meson.build b/pango/meson.build
index 91261274..21b620ec 100644
--- a/pango/meson.build
+++ b/pango/meson.build
@@ -413,6 +413,7 @@ if host_system == 'windows'
   pangowin32_deps = pango_deps + [
     libpango_dep,
     cc.find_library('gdi32'),
+    cc.find_library('dwrite'),
   ]
 
   pangowin32_rc = configure_file(
diff --git a/pango/pangowin32-fontmap.c b/pango/pangowin32-fontmap.c
index 6bc10a7a..a0ccec35 100644
--- a/pango/pangowin32-fontmap.c
+++ b/pango/pangowin32-fontmap.c
@@ -1594,6 +1594,7 @@ pango_win32_insert_font (PangoWin32FontMap *win32fontmap,
                          gboolean           is_synthetic)
 {
   LOGFONTW *lfp2 = NULL;
+  IDWriteGdiInterop *gdi_interop = _pango_win32_setup_dwrite ();
   PangoFontDescription *description;
   PangoWin32Family *win32family;
   PangoWin32Face *win32face;
@@ -1645,6 +1646,12 @@ pango_win32_insert_font (PangoWin32FontMap *win32fontmap,
   PING (("win32face created: %p for %S", win32face, lfp->lfFaceName));
 
   win32face->logfontw = *lfp;
+
+  if (IDGdiInterop_CreateFontFromLOGFONT (gdi_interop,
+                                         &win32face->logfontw,
+                                         &win32face->dwrite_font) != S_OK)
+    g_warning ("Faild to create DirectWriteFont from LOGFONTW");
+
   win32face->description = description;
 
   win32face->coverage = NULL;
@@ -1763,6 +1770,8 @@ pango_win32_face_finalize (GObject *object)
 
   g_slist_free (win32face->cached_fonts);
 //  g_slist_free_full (win32face->cached_fonts, g_object_unref); // This doesn't work.
+  if (win32face->dwrite_font != NULL)
+    IDWriteFont_Release (win32face->dwrite_font);
 
   G_OBJECT_CLASS (pango_win32_family_parent_class)->finalize (object);
 }
diff --git a/pango/pangowin32-private.h b/pango/pangowin32-private.h
index 1c9c1c09..c990fe07 100644
--- a/pango/pangowin32-private.h
+++ b/pango/pangowin32-private.h
@@ -52,6 +52,10 @@
 #define PING(printlist)
 #endif
 
+/* this is a C-compatible counterpart of the DirectWrite headers */
+#define COBJMACROS
+#include "dwrite_c.h"
+
 #include "pangowin32.h"
 #include "pango-font-private.h"
 #include "pango-fontset-private.h"
@@ -155,6 +159,7 @@ struct _PangoWin32Face
 
   gpointer family;
   LOGFONTW logfontw;
+  IDWriteFont *dwrite_font;
   PangoFontDescription *description;
   PangoCoverage *coverage;
   char *face_name;
@@ -277,4 +282,6 @@ HDC             _pango_win32_get_display_dc                 (void);
 
 extern gboolean _pango_win32_debug;
 
+IDWriteGdiInterop * _pango_win32_setup_dwrite (void);
+
 #endif /* __PANGOWIN32_PRIVATE_H__ */
diff --git a/pango/pangowin32.c b/pango/pangowin32.c
index 213a665e..59b0ca9d 100644
--- a/pango/pangowin32.c
+++ b/pango/pangowin32.c
@@ -32,6 +32,8 @@
  */
 #include "config.h"
 
+#include <initguid.h>
+
 #include <string.h>
 #include <stdlib.h>
 #include <glib.h>
@@ -134,6 +136,8 @@ _pango_win32_font_init (PangoWin32Font *win32font)
 }
 
 static GPrivate display_dc_key = G_PRIVATE_INIT ((GDestroyNotify) DeleteDC);
+static GPrivate dwrite_factory_key;
+static GPrivate dwrite_gdi_key;
 
 HDC
 _pango_win32_get_display_dc (void)
@@ -190,6 +194,36 @@ pango_win32_get_debug_flag (void)
   return _pango_win32_debug;
 }
 
+IDWriteGdiInterop *
+_pango_win32_setup_dwrite (void)
+{
+  IDWriteFactory *dwrite_factory = NULL;
+  IDWriteGdiInterop *dwrite_gdi = NULL;
+
+  dwrite_factory = g_private_get (&dwrite_factory_key);
+  if (dwrite_factory == NULL)
+    {
+      if (DWriteCreateFactory (DWRITE_FACTORY_TYPE_SHARED,
+                              &IID_IDWriteFactory,
+                              (IUnknown **)&dwrite_factory) != S_OK)
+        g_warning ("DWrite factory creation failed!");
+      else
+        g_private_set (&dwrite_factory_key, dwrite_factory);
+    }
+
+  dwrite_gdi = g_private_get (&dwrite_gdi_key);
+  if (dwrite_factory != NULL && dwrite_gdi == NULL)
+    {
+      if (IDWriteFactory_GetGdiInterop (dwrite_factory,
+                                       &dwrite_gdi) != S_OK)
+        g_warning ("DWrite GDI interop creation failed!");
+      else
+        g_private_set (&dwrite_gdi_key, dwrite_gdi);
+    }
+
+  return dwrite_gdi;
+}
+
 static void
 _pango_win32_font_class_init (PangoWin32FontClass *class)
 {
@@ -212,6 +246,7 @@ _pango_win32_font_class_init (PangoWin32FontClass *class)
   class->get_metrics_factor = pango_win32_font_real_get_metrics_factor;
 
   _pango_win32_get_display_dc ();
+  _pango_win32_setup_dwrite ();
 }
 
 /**