2.5 Bounding-Box Adjusters
pict : pict?  | 
amt : real?  | 
pict : pict?  | 
h-amt : real?  | 
v-amt : real?  | 
pict : pict?  | 
l-amt : real?  | 
t-amt : real?  | 
r-amt : real?  | 
b-amt : real?  | 
Extends pict’s bounding box by adding the given amounts to the corresponding sides; ascent and descent are extended, too.
(clip-descent pict) → pict?  | 
pict : pict?  | 
Truncates pict’s bounding box by removing the descent part.
(lift-above-baseline pict amt) → pict?  | 
pict : pict?  | 
amt : real?  | 
Lifts pict relative to its baseline, extending the bounding-box height if necessary.
(drop-below-ascent pict amt) → pict?  | 
pict : pict?  | 
amt : real?  | 
Drops pict relative to its ascent line, extending the bounding-box height if necessary.
pict : pict?  | 
Makes the descent 0 and the ascent the same as the height.
pict : pict?  | 
sub-pict : pict?  | 
Assuming that sub-pict can be found within pict, shifts the overall bounding box to that of sub-pict (but preserving all the drawing of pict). The last element, as reported by pict-last is also set to (or (pict-last sub-pict) sub-pict).
pict : pict?  | 
Shifts the given pict’s bounding box to enclose the bounding boxes of all sub-picts (even laundered picts).
pict : pict?  | 
sub-pict : pict?  | 
Returns a pict like pict, but with the last element (as reported by pict-last) set to sub-pict. The sub-pict must exist as a sub-pict within pict.
pict : pict?  | 
sub-pict : pict?  | 
Propagates the last element of sub-pict to pict.
That is, use-last* is like use-last, but the last element of sub-pict is used as the new last element for pict, instead of sub-pict itself – unless (pict-last sub-pict) is #f, in which case sub-pict is used as the last element of pict.