Use the function and/or data in compound-drawing-objects.
lw-gt
compute-drawing-object-from-data object => result
recurse-compute-drawing-object object-or-displayer
object⇩ |
A Lisp object. |
object-or-displayer⇩ |
result |
A boolean. |
The function compute-drawing-object-from-data
computes the drawing for an object.
If object is not a compound-drawing-object, then compute-drawing-object-from-data
just returns nil
.
If object is a compound-drawing-object, then compute-drawing-object-from-data
checks if object has a non-nil value for either function or data. For object to have a non-nil function, this must have been supplied when object was created (for example when creating geometry-drawing-object). data can be passed during creation or set later by using setf with compound-drawing-object-data.
If object has a non-nil function, then compute-drawing-object-from-data
calls function with data as a single argument, and uses the result. Otherwise, if object has a non-nil data, compute-drawing-object-from-data
calls the generic function get-drawing-object
with data as a single argument, and uses the result. If this result is :no-change
, compute-drawing-object-from-data
just returns nil
. get-drawing-object
has a default method that returns :no-change
.
Otherwise, the result must be a "drawing-object-spec", which means either an instance of (a subclass of) drawing-object or a list of "drawing-object-specs". compute-drawing-object-from-data
then sets the sub-object of the object to the result, and returns t
.
For recurse-compute-drawing-object
, object-or-displayer should be an objects-displayer, a pinboard-objects-displayer, a list, or a compound-drawing-object. For other objects recurse-compute-drawing-object
just returns nil
.
recurse-compute-drawing-object
recurses the hierarchy starting at object-or-displayer, and for each compound-drawing-object that it finds calls compute-drawing-object-from-data
.
When it finds an objects-displayer or a pinboard-objects-displayer, recurse-compute-drawing-object
also calls force-objects-redraw when it finishes.
These functions can be called on any thread.
get-drawing-object
and passing the appropriate data. Then the tree can be told to recompute itself by calling recurse-compute-drawing-object
.recurse-compute-drawing-object
is applied to objects-displayer or pinboard-objects-displayer. You will have to do it yourself by using force-objects-redraw on the root of the hierarchy or hierarchies which need redrawing.recurse-compute-drawing-object
does not check against duplication, so if the same object appears in the hierarchy more than once, it will be updated repeatedly.
geometry-drawing-object
compound-drawing-object
14.1 Lower level - drawing objects and objects displayers
CAPI User Guide and Reference Manual (Unix version) - 01 Dec 2021 19:33:10