exploit record-dc% to keep picts from drawing outside

of their bounding boxes

collects/drracket/private/language.rkt

@@ -478,6 +478,7 @@
     (define d (dyn pict-descent pict))
     (define rdc (new record-dc%))
     (send rdc set-smoothing 'aligned)
+    (send rdc set-clipping-rect 0 0 w h)
     (dyn draw-pict pict rdc 0 0)
     (define recorded-datum (send rdc get-recorded-datum))
     (new pict-snip:pict-snip% [w w] [h h] [d d] [a a] [recorded-datum recorded-datum]))