gadget: Update docs

Make it clear that out_clip must be set.

diff --git a/gtk/gtkcsscustomgadget.c b/gtk/gtkcsscustomgadget.c
index d627a1904f1158e6e9dbe7998c54fb1929a2faf3..60a1881ba9b4c32e735b6e0041a5030497fc25bd 100644 (file)
--- a/gtk/gtkcsscustomgadget.c
+++ b/gtk/gtkcsscustomgadget.c
@@ -76,6 +76,9 @@
  * don't have sub-gadgets of child widgets don't need a GtkCssAllocateFunc
  * (although it is still required to call gtk_css_gadget_allocate() on them).
  *
+ * Note that @out_clip *must* be set to meaningful values. If in doubt,
+ * just set it to the allocation.
+ *
  * GtkCssDrawFunc:
  * @gadget: the #GtkCssCustomGadget
  * @cr: the cairo context to draw on