[reportlab-users] Status of clipping paths?

Robin Becker robin at reportlab.com
Tue Oct 29 06:58:10 EDT 2013


after reading this from the PDF spec

"There is no way to enlarge the current clipping path or to set a new clipping
path without reference to the current one. However, since the clipping path is
part of the graphics state, its effect can be localized to specific graphics
objects by enclosing the modification of the clipping path and the painting of
those objects between a pair of q and Q operators (see Section 4.3.1, “Graphics
State Stack”). Execution of the Q operator causes the clipping path to revert to
the value that was saved by the q operator before the clipping path was modified."

I think we abandoned the idea of trying to reset a clipping path in PDF. It
could be done by placing an outer save state around each page. The reset
operation would then need to restore the graphics state and immediately start a
new save state with everything copied across from the old state except the
clipping path; I think that would be quite hard.
Robin Becker

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