Version 5.0 The LEDA User Manual

window& W ≫ segment& s reads a segment s: use the left button to define the
start and end point of s.
window& W ≫ ray& r reads a ray r: use the left button to define the start
point and a second point on r.
window& W ≫ line& l reads a line l: use the left button to define two
different points on l.
window& W ≫ circle& C reads a circle C: use the left button to define the
center of C and a point on C.
window& W ≫ rectangle& R reads a rectangle R: use the left button to define
two opposite corners of R.
window& W ≫ triangle& T reads a triangle T : use the left button to define the
corners of T .
window& W ≫ polygon& P reads a polygon P : use the left button to define
the sequence of vertices of P , end the sequence by
clicking the right button.
window&
W ≫ gen polygon& P
reads a generalized polygon P ; input the polygons
defining P and end the input by clicking the middle
button.
list W.read polygon( ) as above, however, returns list of vertices.
As long as an input operation has not been completed the last read point can be erased
by simultaneously pressing the shift key and the left mouse button.
3.8 Non-Member Functions
int read mouse(window ∗ & w, double& x, double& y)
int get mouse(window ∗ & w, double& x, double& y)
waits for mouse input, assigns a pointer to the corresponding
window to w and the position in ∗w to
(x, y) and returns the pressed button.
non-blocking variant of read mouse, returns
NO BUTTON if no button was pressed.
void put back event( ) puts last handled event back to the event queue.
3.9 Panel Operations
The panel section of a window is used for displaying text messages and for updating the
values of variables. It consists of a list of panel items and a list of buttons. The operations