[gtk/gtk-4-4] macos: fix scale on macOS 12 beta

[Matthias Clasen <matthiasc src gnome org>]

commit 63583c15db94825529f6232feca7bd4671c45db2
Author: Christian Hergert <chergert redhat com>
Date:   Thu Oct 14 14:46:30 2021 -0700

    macos: fix scale on macOS 12 beta
    
    This is a port of the fix in the quartz backend to the new macOS backend.
    
    From the original commit:
    
    In macOS-12.sdk CGContextConverSizeToDeviceSpace returns a negative
    height and passing that to CGContextScaleCTM in turn causes the cairo
    surface to draw outside the window where it can't be seen. Passing the
    absolute values of the scale factors fixes the display on macOS 12 without
    affecting earlier macOS versions.

 gdk/macos/gdkmacossurface.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/gdk/macos/gdkmacossurface.c b/gdk/macos/gdkmacossurface.c
index 88be1f513d..b8068ecded 100644
--- a/gdk/macos/gdkmacossurface.c
+++ b/gdk/macos/gdkmacossurface.c
@@ -807,7 +807,7 @@ _gdk_macos_surface_acquire_context (GdkMacosSurface *self,
       scale = CGSizeMake (1.0, 1.0);
       scale = CGContextConvertSizeToDeviceSpace (cg_context, scale);
 
-      CGContextScaleCTM (cg_context, 1.0 / scale.width, 1.0 / scale.height);
+      CGContextScaleCTM (cg_context, 1.0 / fabs (scale.width), 1.0 / fabs (scale.height));
     }
 
   return cg_context;