Implement a simple dragging operation, which means the pane scrolls as much as the user drags.
capi
start-pane-drag-operation pane x y &key override-cursor
pane-drag-operation-update pane x y
end-pane-drag-operation pane x y
pane⇩ |
A simple-pane with scrollbar(s). |
Integers. | |
override-cursor⇩ |
A cursor specification or nil . |
The functions start-pane-drag-operation
, pane-drag-operation-update
and end-pane-drag-operation
together implement a simple dragging operation, which means that pane scrolls as much as the user move the cursor. The scrolling happens by a call to scroll with the appropriate parameters, in the dimension(s) for which pane has scrollbar(s).
start-pane-drag-operation
initializes the dragging operation on pane. If override-cursor cursor is non-nil, the overriding cursor is set internally (not affecting the value that interface-override-cursor accesses). override-cursor defaults to :move
.
pane-drag-operation-update
performs the dragging operation and calls scroll with the appropriate arguments to scroll pane, in the direction(s) that the pane has scrollbar(s). pane is scrolled based on the difference between the values of x and y in the calls to pane-drag-operation-update
and start-pane-drag-operation
.
end-pane-drag-operation
stops the dragging operation, and resets the override cursor to the value of that interface-override-cursor accesses. It ignores x and y.
If pane-drag-operation-update
or end-pane-drag-operation
are called without a preceding call to start-pane-drag-operation
or after a call to end-pane-drag-operation
without following call to start-pane-drag-operation
they do nothing.
These functions are intended to be used as callbacks in input model of output-pane and its subclasses.
(example-edit-file "capi/graphics/tracking-pinboard-layout.lisp")
CAPI User Guide and Reference Manual (Unix version) - 01 Dec 2021 19:32:42