Copies a rectangular area from one port to another.
graphics-ports
copy-area to-port from-port to-x to-y width height from-x from-y &rest args
to-port⇩ |
A graphics port. |
from-port⇩ |
A graphics port. |
to-x⇩ |
A real number. |
to-y⇩ |
A real number. |
width⇩ |
A real number. |
height⇩ |
A real number. |
from-x⇩ |
A real number. |
from-y⇩ |
A real number. |
args⇩ |
graphics-state parameters passed as keyword arguments. |
The function copy-area
copies a rectangular area from from-port to to-port, taking account of transformations.
In drawing-mode :compatible
(old drawing mode), copy-area
is exactly the same as copy-pixels.
In drawing-mode :quality
(the default), copy-area
copies a rectangular area from one port to another. The transform, mask, mask-transform, compositing-mode and shape-mode from to-port's graphics-state are all used, unless overridden in args. to-port and from-port need not have the same depth and can be the same object. The corners of the copied rectangle are (from-x from-y), (from-x+width from-y), (from-x+width from-y+height) and (from-x from-y+height), which are interpreted as pixel positions in the window coordinates of from-port, that is, they are not transformed by from-port's transform. The top left of the rectangle is copied to (to-x to-y) in to-port's coordinates.
The main difference between copy-area
and copy-pixels in drawing-mode :quality
is when copying from a displayed window.
copy-area
always copies using the correct transformation of the target, but that it means that it may copy from an obscured part of the window and hence copy the wrong thing. copy-pixels generates an exposure event on the target port instead of copying obscured areas, but to do that it has to ignore the transformation.
(example-edit-file "capi/graphics/compositing-mode")
CAPI User Guide and Reference Manual (Unix version) - 01 Dec 2021 19:33:02