Merge branch 'scale-factor-cleanup' into 'main'

wayland: Be more careful about scale-factor

See merge request GNOME/gtk!5775

2 files changed, 16 insertions, 6 deletions

diff --git a/gdk/gdksurface.c b/gdk/gdksurface.c
index b7e285f2ae..7120da78db 100644
--- a/gdk/gdksurface.c
+++ b/gdk/gdksurface.c
@@ -572,6 +572,9 @@ gdk_surface_class_init (GdkSurfaceClass *klass)
    * GdkSurface:scale-factor: (attributes org.gtk.Property.get=gdk_surface_get_scale_factor)
    *
    * The scale factor of the surface.
+   *
+   * The scale factor is the next larger integer,
+   * compared to [property@Gdk.Surface:scale].
    */
   properties[PROP_SCALE_FACTOR] =
       g_param_spec_int ("scale-factor", NULL, NULL,
@@ -2622,7 +2625,7 @@ gdk_surface_get_frame_clock (GdkSurface *surface)
  * pixel-based data the scale value can be used to determine whether to
  * use a pixel resource with higher resolution data.
  *
- * The scale may change during the lifetime of the surface.
+ * The scale factor may change during the lifetime of the surface.
  *
  * Returns: the scale factor
  */
@@ -2641,6 +2644,13 @@ gdk_surface_get_scale_factor (GdkSurface *surface)
  * Returns the internal scale that maps from surface coordinates
  * to the actual device pixels.
  *
+ * When the scale is bigger than 1, the windowing system prefers to get
+ * buffers with a resolution that is bigger than the surface size (e.g.
+ * to show the surface on a high-resolution display, or in a magnifier).
+ *
+ * Compare with [method@Gdk.Surface.get_scale_factor], which returns the
+ * next larger integer.
+ *
  * The scale may change during the lifetime of the surface.
  *
  * Returns: the scale
diff --git a/gdk/wayland/gdksurface-wayland.c b/gdk/wayland/gdksurface-wayland.c
index ca27f65373..0cebc00474 100644
--- a/gdk/wayland/gdksurface-wayland.c
+++ b/gdk/wayland/gdksurface-wayland.c
@@ -261,11 +261,12 @@ gdk_wayland_surface_update_size (GdkSurface               *surface,
                                  const GdkFractionalScale *scale)
 {
   GdkWaylandSurface *impl = GDK_WAYLAND_SURFACE (surface);
-  gboolean width_changed, height_changed, scale_changed;
+  gboolean width_changed, height_changed, scale_changed, scale_factor_changed;
 
   width_changed = surface->width != width;
   height_changed = surface->height != height;
   scale_changed = !gdk_fractional_scale_equal (&impl->scale, scale);
+  scale_factor_changed = gdk_fractional_scale_to_int (&impl->scale) != gdk_fractional_scale_to_int (scale);
 
   if (!width_changed && !height_changed && !scale_changed)
     return;
@@ -295,10 +296,9 @@ gdk_wayland_surface_update_size (GdkSurface               *surface,
   if (height_changed)
     g_object_notify (G_OBJECT (surface), "height");
   if (scale_changed)
-    {
-      g_object_notify (G_OBJECT (surface), "scale-factor");
-      g_object_notify (G_OBJECT (surface), "scale");
-    }
+    g_object_notify (G_OBJECT (surface), "scale");
+  if (scale_factor_changed)
+    g_object_notify (G_OBJECT (surface), "scale-factor");
 
   _gdk_surface_update_size (surface);
 }