Version 5.0 The LEDA User Manual

18. The buttons per line parameter (default ∞) defines the maximal number of buttons
in one line of the panel section.
19. The precision parameter (default 16) defines the precision that is used for representing
window coordinates, more precisely, all x and y coordinates generated by window
input operations are doubles whose mantissa are truncated after precision − 1 bits
after the binary point.
In addition to call-back (handler) functions LEDA windows now also support the usage
of function objects. Function object classes have to be derived from the window handler
base class.
class window_handler {
...
virtual void operator()() { }
// parameter access functions
double get_double(int nr) const;
int get_int() const;
window* get_window_ptr() const;
char* get_char_ptr() const;
};
Derived classes have to implement the handling function in the definition of the operator( )
method. The different get methods can be called to retrieve parameters.
If both, a handler function and an object for the same action is supplied the object has
higher priority.
#include < LEDA/graphics/window.h >
2. Creation
window W ;
creates a squared window with maximal possible edge length (minimum
of width and height of the display).
window W (const char ∗ label);
window W (int w, int h);
creates a maximal squared window with frame label label.
creates a window W of physical size w pixels × h pixels .
window W (int w, int h, const char ∗ label);
creates a window W of physical size w pixels × h pixels and frame
label label.