Learning Perl/Tk

9.12. Moving Items Around

Once an item has been created on the canvas, you can move it by using one of two methods: move or coords. The move method takes a tag or ID to indicate which items to move and the amounts to add to the x and y coordinates:

$canvas->move(tag/id, xdistance, ydistance);

For instance, the following code will move items with the "blue" tag 100 pixels in the x direction and 100 pixels in the y direction:

$canvas->move("blue", 100, 100);

To move an item in the negative direction, simply specify a negative value for the xdistance and/or ydistance. The other method, coords, allows you to explicitly specify a new x and y location for the first item found that is identified by the tag or ID:

$canvas->coords(tag/id, newx, newy);

If the item requires more than one set of x,y coordinates, you simply continue to specify them:

$canvas->coords(tag/id, newx1, newy1, newx2, newy2...);

You can also find out where an item currently is in the canvas by using coords and not specifying the x or y coordinates:

@coords_list = $canvas->coords(tag/id);

Remember, the coords method only applies to the first item it finds that matches the given tag or ID.