GdkWin32: Scale text with DPI like in GTK3 with SYSTEM_DPI_AWARENESS

Right now we only support system DPI awareness in GTK4. In that case
it makes sense to scale text with the DPI of the primary monitor, like
done in GTK3.

We plan to land support for proper fractional scaling in Gdk/Win32, so
in the future the "gtk-xft-dpi" setting will be gathered as intended,
i.e. for text magnification, as an a11y feature.

1 files changed, 20 insertions, 0 deletions

diff --git a/gdk/win32/gdkproperty-win32.c b/gdk/win32/gdkproperty-win32.c
index f919e53e9c..b8197495f2 100644
--- a/gdk/win32/gdkproperty-win32.c
+++ b/gdk/win32/gdkproperty-win32.c
@@ -31,6 +31,7 @@
 
 #include "gdkdisplayprivate.h"
 #include "gdkprivate-win32.h"
+#include "gdkdisplay-win32.h"
 #include "gdkwin32.h"
 
 static char *
@@ -162,6 +163,25 @@ _gdk_win32_get_setting (const char *name,
       g_value_set_int (value, 1);
       return TRUE;
     }
+  else if (strcmp ("gtk-xft-dpi", name) == 0)
+    {
+      GdkWin32Display *display = GDK_WIN32_DISPLAY (_gdk_display);
+
+      if (display->dpi_aware_type == PROCESS_SYSTEM_DPI_AWARE &&
+          !display->has_fixed_scale)
+        {
+          int dpi = GetDeviceCaps (GetDC (NULL), LOGPIXELSX);
+          if (dpi >= 96)
+            {
+              int xft_dpi = 1024 * dpi / display->surface_scale;
+              g_value_set_int (value, xft_dpi);
+              GDK_NOTE(MISC, g_print ("gdk_screen_get_setting(\"%s\") : %d\n", name, xft_dpi));
+              return TRUE;
+            }
+        }
+
+      return FALSE;
+    }
   else if (strcmp ("gtk-xft-hintstyle", name) == 0)
     {
       g_value_set_static_string (value, "hintfull");