[gtk: 1/2] gdk: Subtract base size when checking aspect ratio

[Matthias Clasen <matthiasc src gnome org>]

commit b36258f2042d610e59a04dde7eaad0aa37a249bf
Author: Vlad Zahorodnii <vlad zahorodnii kde org>
Date:   Sun Jan 19 01:56:35 2020 +0200

    gdk: Subtract base size when checking aspect ratio
    
    According to the ICCCM spec [1], one should subtract the base size from
    the window size before checking that the aspect ratio falls in range.
    
    This change fixes shrinking Firefox Picture-in-Picture windows when
    running KDE Plasma (with KWin as the window manager).
    
    [1] https://tronche.com/gui/x/icccm/sec-4.html#s-4.1.2.3

 gdk/gdksurface.c | 16 ++++++++++++++++
 1 file changed, 16 insertions(+)
---
diff --git a/gdk/gdksurface.c b/gdk/gdksurface.c
index 8424576238..dbc709bea6 100644
--- a/gdk/gdksurface.c
+++ b/gdk/gdksurface.c
@@ -1726,6 +1726,16 @@ gdk_surface_constrain_size (GdkGeometry    *geometry,
     {
       gint delta;
 
+      if (flags & GDK_HINT_BASE_SIZE)
+        {
+          width -= base_width;
+          height -= base_height;
+          min_width -= base_width;
+          min_height -= base_height;
+          max_width -= base_width;
+          max_height -= base_height;
+        }
+
       if (geometry->min_aspect * height > width)
         {
           delta = FLOOR (height - width / geometry->min_aspect, yinc);
@@ -1751,6 +1761,12 @@ gdk_surface_constrain_size (GdkGeometry    *geometry,
                 height += delta;
             }
         }
+
+      if (flags & GDK_HINT_BASE_SIZE)
+        {
+          width += base_width;
+          height += base_height;
+        }
     }
 
 #undef FLOOR