'''piemenu''' is a package to create pie menus.



** Disambiguation **

        [http://art.net/Studios/Hackers/Hopkins/Don/piemenus/%|%piemenu for Tk] ,by Don Hopkins:   



** Description **

Current version : Beta, '''0.3''', home
[http://piemenu.sourceforge.net/index.html], download
[http://sourceforge.net/project/showfiles.php?group_id=204581], manual (draft)
[http://piemenu.sourceforge.net/piemenu.html]


This is an ongoing project. Hopefully this or some other incarnation of pie menus will prove to be a good widget for Tk. Lack of anti-aliasing and transparency is a problem in creating good looking curved canvas buttons. Ideas and help are invited and welcome. [dzach]
----
This package provides a single command '''piemenu''', in a similar manner with Tk's [menu] command. The '''piemenu''' command is used to create either a toplevel or a canvas menu. If the parent of the ''pathName'' provided at creation time is a canvas widget, then the pie menu is created in that canvas. Otherwise it is created in a new toplevel window.

Here is an example of how a pie menu looks like:

[http://piemenu.sourceforge.net/images/piemenu4.png]

'''Why use a pie menu ?'''

   * The main reason is because it's far easier to use on touch screens, on mobile devices where simplicity matters.
   * It has different aesthetics than the usual rectangular popup or drop down menus, and can make tcl/tk look nice.
   * Round shapes are usually easier to the eye (can be easily made cluttered though, like everything else).
   * It can help give a minimalistic appearance to an interface, when this is a requirement (e.g. OLPC's Sugar interface [http://wiki.laptop.org/go/Sugar]).
   * It gives the benefits of applying Fitts's Law [http://en.wikipedia.org/wiki/Fitts_law] to popup menus.
----
'''BUGS'''

The piemenu package code needs improvement, so bug reports and patches are welcome.
----
[schlenk] Did you consider to put this into tklib? Looks like a nice and useful package.

[dzach] I think it needs further development. It's still in beta, and there are a number of subcommands that are similar to tk's menu command that are not yet implemented. There is also the possibility to make a round (or elliptical) popup piemenu that does not show a rectangular top level window. However, if putting it in tklib would help develop it further, by attracting some more developers who find it useful, I'd be glad to. 

[APE] I modified the behaviour when user clicks (Button-1) on the canvas outside the menu commands. In this case, the menu actions are cancelled, which is the desired behaviour I suppose.
To do so, I added a tag "pmcmd" in the list of tags of each command, and a variable pm which records the current posted menu at the end of the draw and post functions :

======
set pm(current) $W.$menu
======

When drawing or posting the menu, the binding is associated to this function : bind $W <Button-1> [list piemenu::Button-1-outside %W]

======
proc Button-1-outside {W} {
        upvar ::piemenu::pm pm
        if {"pmcmd" ni [$W gettags current]} {
                # button-1 activated outside a piemenu command : unpost menu
                $pm(current) unpost
        }
}
======

[APE] There is a side effect on the central button command : if the delayed command is activated, the "normal" command is activated when the button is released.
Proposed modification : a variable pm(delcmdact) is set to "1" if the delayed command is activated, so when the button-1 is released the "normal" command is not called :"

======
if {[info exists opt($btn,-command)] && !$pm(delcmdact)} {
                after 0 $opt($btn,-command)
        }
======
 
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