[pango/pango1-dwrite] Implement is_hinted for PangoWin32Font

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

commit f7e6cb0179e6553be5a4b998084a2b10c027f520
Author: Chun-wei Fan <fanchunwei src gnome org>
Date:   Mon Jul 11 19:09:01 2022 +0800

    Implement is_hinted for PangoWin32Font
    
    This is the GDI+ implementation for querying whether a given font supports
    hinting, which will be meant for Windows 7 and 8, since the DirectWrite
    counterpart is only available for Windows 8.1 or later, which will be in
    a later patch.
    
    Link to gdiplus.lib as we are using the flat C APIs from there, which sadly we
    had to add into our own private headers since we can't just include the GDI+
    headers from our plain-C sources.

 pango/meson.build            |  1 +
 pango/pangocairo-win32font.c |  2 +-
 pango/pangowin32-fontmap.c   |  1 +
 pango/pangowin32-private.h   |  6 ++++
 pango/pangowin32.c           | 70 ++++++++++++++++++++++++++++++++++++++++++++
 5 files changed, 79 insertions(+), 1 deletion(-)
---
diff --git a/pango/meson.build b/pango/meson.build
index cc301f0b7..efcc0c936 100644
--- a/pango/meson.build
+++ b/pango/meson.build
@@ -430,6 +430,7 @@ if host_system == 'windows'
   pangowin32_deps = pango_deps + [
     libpango_dep,
     cc.find_library('gdi32'),
+    cc.find_library('gdiplus'),
   ]
   if enable_dwrite_support
     pangowin32_deps += cc.find_library('dwrite')
diff --git a/pango/pangocairo-win32font.c b/pango/pangocairo-win32font.c
index 9f4f5c140..e79c4e9f6 100644
--- a/pango/pangocairo-win32font.c
+++ b/pango/pangocairo-win32font.c
@@ -267,7 +267,7 @@ _pango_cairo_win32_font_new (PangoCairoWin32FontMap     *cwfontmap,
                                       &face->logfontw,
                                       win32font->size,
                                       &win32font->logfontw);
-
+  win32font->is_hinted = pango_win32_font_check_is_hinted (win32font);
   cairo_matrix_init_identity (&font_matrix);
 
   cairo_matrix_scale (&font_matrix, size, size);
diff --git a/pango/pangowin32-fontmap.c b/pango/pangowin32-fontmap.c
index 88ab343c3..cfe7f366d 100644
--- a/pango/pangowin32-fontmap.c
+++ b/pango/pangowin32-fontmap.c
@@ -1151,6 +1151,7 @@ pango_win32_font_neww (PangoFontMap   *fontmap,
 
   result->size = size;
   _pango_win32_make_matching_logfontw (fontmap, lfp, size, &result->logfontw);
+  result->is_hinted = pango_win32_font_check_is_hinted (result);
 
   return result;
 }
diff --git a/pango/pangowin32-private.h b/pango/pangowin32-private.h
index 9bbc3b22c..d23f74423 100644
--- a/pango/pangowin32-private.h
+++ b/pango/pangowin32-private.h
@@ -215,6 +215,9 @@ struct _PangoWin32Font
    */
   gboolean in_cache;
   GHashTable *glyph_info;
+
+  /* whether the font supports hinting */
+  gboolean is_hinted;
 };
 
 struct _PangoWin32FontClass
@@ -365,6 +368,9 @@ void            pango_win32_insert_font                       (PangoWin32FontMap
                                                                gpointer           dwrite_font,
                                                                gboolean           is_synthetic);
 
+_PANGO_EXTERN
+gboolean        pango_win32_font_check_is_hinted              (PangoWin32Font    *font);
+
 void            pango_win32_dwrite_font_map_init              (PangoWin32FontMap *map);
 
 void            pango_win32_dwrite_font_map_populate          (PangoWin32FontMap *map);
diff --git a/pango/pangowin32.c b/pango/pangowin32.c
index eed92dde7..003bd1015 100644
--- a/pango/pangowin32.c
+++ b/pango/pangowin32.c
@@ -56,6 +56,7 @@ static gboolean pango_win32_font_real_select_font      (PangoFont *font,
                                                        HDC        hdc);
 static void     pango_win32_font_real_done_font        (PangoFont *font);
 static double   pango_win32_font_real_get_metrics_factor (PangoFont *font);
+static gboolean pango_win32_font_is_hinted             (PangoFont *font);
 
 static void                  pango_win32_get_item_properties    (PangoItem        *item,
                                                                 PangoUnderline   *uline,
@@ -187,6 +188,7 @@ _pango_win32_font_class_init (PangoWin32FontClass *class)
 {
   GObjectClass *object_class = G_OBJECT_CLASS (class);
   PangoFontClass *font_class = PANGO_FONT_CLASS (class);
+  PangoFontClassPrivate *pclass;
 
   object_class->finalize = pango_win32_font_finalize;
   object_class->dispose = pango_win32_font_dispose;
@@ -203,6 +205,9 @@ _pango_win32_font_class_init (PangoWin32FontClass *class)
   class->done_font = pango_win32_font_real_done_font;
   class->get_metrics_factor = pango_win32_font_real_get_metrics_factor;
 
+  pclass = g_type_class_get_private ((GTypeClass *) class, PANGO_TYPE_FONT);
+  pclass->is_hinted = pango_win32_font_is_hinted;
+
   _pango_win32_get_display_dc ();
 }
 
@@ -647,6 +652,71 @@ pango_win32_font_real_get_metrics_factor (PangoFont *font)
   return PANGO_SCALE;
 }
 
+gboolean
+pango_win32_font_check_is_hinted (PangoWin32Font *font)
+{
+  LOGFONTW lfw;
+  HDC hdc;
+  HFONT hfont, oldhfont;
+  GpGraphics *gpgraphics = NULL;
+  TextRenderingHint mode;
+  gboolean is_hinted = FALSE;
+  GpStatus status;
+  GdiplusStartupInput input;
+  ULONG_PTR gdiplusToken = 0;
+
+  lfw = font->logfontw;
+  memset (&input, 0, sizeof (input));
+  input.GdiplusVersion = 1;
+
+  if ((hfont = CreateFontIndirectW (&lfw)) == NULL)
+    return FALSE;
+
+  hdc = _pango_win32_get_display_dc ();
+
+  if ((oldhfont = SelectObject (hdc, hfont)) == NULL)
+    {
+      DeleteObject (hfont);
+      return FALSE;
+    }
+
+  if (GdiplusStartup (&gdiplusToken, &input, NULL) != Ok)
+    return FALSE;
+
+  if (GdipCreateFromHDC (hdc, &gpgraphics) == Ok &&
+      GdipGetTextRenderingHint (gpgraphics, &mode) == Ok)
+    {
+      if (mode == TextRenderingHintSingleBitPerPixelGridFit ||
+          mode == TextRenderingHintAntiAliasGridFit ||
+          mode == TextRenderingHintClearTypeGridFit)
+        is_hinted = TRUE;
+      else if (mode == TextRenderingHintSystemDefault)
+        {
+          BOOL sys_is_hinted = FALSE;
+
+          if (SystemParametersInfoW (SPI_GETFONTSMOOTHING, 0, &sys_is_hinted, 0))
+            is_hinted = sys_is_hinted;
+        }
+      else
+        is_hinted = FALSE;
+    }
+
+  GdipDeleteGraphics (gpgraphics);
+  GdiplusShutdown (gdiplusToken);
+  SelectObject (hdc, oldhfont);
+  DeleteObject (hfont);
+
+  return is_hinted;
+}
+
+static gboolean
+pango_win32_font_is_hinted (PangoFont *font)
+{
+  g_return_val_if_fail (PANGO_WIN32_IS_FONT (font), FALSE);
+
+  return PANGO_WIN32_FONT (font)->is_hinted;
+}
+
 /**
  * pango_win32_font_logfont:
  * @font: a `PangoFont` which must be from the Win32 backend