canvas::track::lines - Manage a group of rubber band lines
package require
Tcl 8.5
package require
Tk 8.5
package require
canvas::tag ?0.1?
::canvas::track lines objectName canvas
objectName destroy
objectName start current p...
objectName move current
objectName done
This package provides a utility class managing the drawing of set of
semi-crosshair (rubberband) lines.
-
::canvas::track lines objectName
canvas
- This, the class command, creates and configures a new
instance of the tracker, named objectName. The instance will be
connected to the specified canvas widget.
The result of the command is the fully qualified name of the instance
command.
Instances of this class provide the following API:
-
objectName destroy
- This method destroys the instance and releases all its
internal resources.
This operation does destroy the items representing the tracked lines. It
does not destroy the attached canvas.
The result of the method is an empty string.
-
objectName start current
p...
- This method starts the tracking of a set of lines, one line
per point p, which specifies the destination end-point of each
line. All lines will have current as a common end-point.
Note that a previously tracked set of lines is removed.
The result of the method is an empty string.
Each point is specified through a 2-element list containing its x- and
y-coordinates, in this order.
-
objectName move current
- This method updates the shared end-point of all rubberbands
and redraws them.
The result of the method is an empty string.
The point is specified through a 2-element list containing its x- and
y-coordinates, in this order.
-
objectName done
- This method ends the tracking of the current set of lines
and removes them from the canvas.
This document, and the package it describes, will undoubtedly contain bugs and
other problems. Please report such in the category
canvas of the
Tklib Trackers [
http://core.tcl.tk/tklib/reportlist]. Please also
report any ideas for enhancements you may have for either package and/or
documentation.
canvas, crosshair, rubberband, tracking