Checked in some new Tk demos that I wrote a while ago.

1 files changed, 244 insertions, 0 deletions

diff --git a/Demo/tkinter/guido/canvasevents.py b/Demo/tkinter/guido/canvasevents.py
new file mode 100644
index 0000000..60f4096
--- /dev/null
+++ b/Demo/tkinter/guido/canvasevents.py
@@ -0,0 +1,244 @@
+#! /usr/bin/env python
+
+from Tkinter import *
+from Canvas import Oval, Group, CanvasText
+
+
+# Fix a bug in Canvas.Group as distributed in Python 1.4.  The
+# distributed bind() method is broken.  This is what should be used:
+
+class Group(Group):
+    def bind(self, sequence=None, command=None):
+	return self.canvas.tag_bind(self.id, sequence, command)
+
+class Object:
+
+    """Base class for composite graphical objects.
+
+    Objects belong to a canvas, and can be moved around on the canvas.
+    They also belong to at most one ``pile'' of objects, and can be
+    transferred between piles (or removed from their pile).
+
+    Objects have a canonical ``x, y'' position which is moved when the
+    object is moved.  Where the object is relative to this position
+    depends on the object; for simple objects, it may be their center.
+
+    Objects have mouse sensitivity.  They can be clicked, dragged and
+    double-clicked.  The behavior may actually determined by the pile
+    they are in.
+
+    All instance attributes are public since the derived class may
+    need them.
+
+    """
+
+    def __init__(self, canvas, x=0, y=0, fill='red', text='object'):
+	self.canvas = canvas
+	self.x = x
+	self.y = y
+	self.pile = None
+	self.group = Group(self.canvas)
+	self.createitems(fill, text)
+
+    def __str__(self):
+	return str(self.group)
+
+    def createitems(self, fill, text):
+	self.__oval = Oval(self.canvas,
+			   self.x-20, self.y-10, self.x+20, self.y+10,
+			   fill=fill, width=3)
+	self.group.addtag_withtag(self.__oval)
+	self.__text = CanvasText(self.canvas,
+			   self.x, self.y, text=text)
+	self.group.addtag_withtag(self.__text)
+
+    def moveby(self, dx, dy):
+	if dx == dy == 0:
+	    return
+	self.group.move(dx, dy)
+	self.x = self.x + dx
+	self.y = self.y + dy
+
+    def moveto(self, x, y):
+	self.moveby(x - self.x, y - self.y)
+
+    def transfer(self, pile):
+	if self.pile:
+	    self.pile.delete(self)
+	    self.pile = None
+	self.pile = pile
+	if self.pile:
+	    self.pile.add(self)
+
+    def tkraise(self):
+	self.group.tkraise()
+
+
+class Bottom(Object):
+
+    """An object to serve as the bottom of a pile."""
+
+    def createitems(self, *args):
+	self.__oval = Oval(self.canvas,
+			   self.x-20, self.y-10, self.x+20, self.y+10,
+			   fill='gray', outline='')
+	self.group.addtag_withtag(self.__oval)
+
+
+class Pile:
+
+    """A group of graphical objects."""
+
+    def __init__(self, canvas, x, y, tag=None):
+	self.canvas = canvas
+	self.x = x
+	self.y = y
+	self.objects = []
+	self.bottom = Bottom(self.canvas, self.x, self.y)
+	self.group = Group(self.canvas, tag=tag)
+	self.group.addtag_withtag(self.bottom.group)
+	self.bindhandlers()
+
+    def bindhandlers(self):
+	self.group.bind('<1>', self.clickhandler)
+ 	self.group.bind('<Double-1>', self.doubleclickhandler)
+
+    def add(self, object):
+	self.objects.append(object)
+	self.group.addtag_withtag(object.group)
+	self.position(object)
+
+    def delete(self, object):
+	object.group.dtag(self.group)
+	self.objects.remove(object)
+
+    def position(self, object):
+	object.tkraise()
+	i = self.objects.index(object)
+	object.moveto(self.x + i*4, self.y + i*8)
+
+    def clickhandler(self, event):
+	pass
+
+    def doubleclickhandler(self, event):
+	pass
+
+
+class MovingPile(Pile):
+
+    def bindhandlers(self):
+	Pile.bindhandlers(self)
+	self.group.bind('<B1-Motion>', self.motionhandler)
+	self.group.bind('<ButtonRelease-1>', self.releasehandler)
+
+    movethis = None
+
+    def clickhandler(self, event):
+	tags = self.canvas.gettags('current')
+	for i in range(len(self.objects)):
+	    o = self.objects[i]
+	    if o.group.tag in tags:
+		break
+	else:
+	    self.movethis = None
+	    return
+	self.movethis = self.objects[i:]
+	for o in self.movethis:
+	    o.tkraise()
+	self.lastx = event.x
+	self.lasty = event.y
+
+    doubleclickhandler = clickhandler
+
+    def motionhandler(self, event):
+	if not self.movethis:
+	    return
+	dx = event.x - self.lastx
+	dy = event.y - self.lasty
+	self.lastx = event.x
+	self.lasty = event.y
+	for o in self.movethis:
+	    o.moveby(dx, dy)
+
+    def releasehandler(self, event):
+	objects = self.movethis
+	if not objects:
+	    return
+	self.movethis = None
+	self.finishmove(objects)
+
+    def finishmove(self, objects):
+	for o in objects:
+	    self.position(o)
+
+
+class Pile1(MovingPile):
+
+    x = 50
+    y = 50
+    tag = 'p1'
+
+    def __init__(self, demo):
+	self.demo = demo
+	MovingPile.__init__(self, self.demo.canvas, self.x, self.y, self.tag)
+
+    def doubleclickhandler(self, event):
+	try:
+	    o = self.objects[-1]
+	except IndexError:
+	    return
+	o.transfer(self.other())
+	MovingPile.doubleclickhandler(self, event)
+
+    def other(self):
+	return self.demo.p2
+
+    def finishmove(self, objects):
+	o = objects[0]
+	p = self.other()
+	x, y = o.x, o.y
+	if (x-p.x)**2 + (y-p.y)**2 < (x-self.x)**2 + (y-self.y)**2:
+	    for o in objects:
+		o.transfer(p)
+	else:
+	    MovingPile.finishmove(self, objects)
+
+class Pile2(Pile1):
+
+    x = 150
+    y = 50
+    tag = 'p2'
+
+    def other(self):
+	return self.demo.p1
+
+
+class Demo:
+
+    def __init__(self, master):
+	self.master = master
+	self.canvas = Canvas(master,
+			     width=200, height=200,
+			     background='yellow',
+			     relief=SUNKEN, borderwidth=2)
+	self.canvas.pack(expand=1, fill=BOTH)
+	self.p1 = Pile1(self)
+	self.p2 = Pile2(self)
+	o1 = Object(self.canvas, fill='red', text='o1')
+	o2 = Object(self.canvas, fill='green', text='o2')
+	o3 = Object(self.canvas, fill='light blue', text='o3')
+	o1.transfer(self.p1)
+	o2.transfer(self.p1)
+	o3.transfer(self.p2)
+
+
+# Main function, run when invoked as a stand-alone Python program.
+
+def main():
+    root = Tk()
+    demo = Demo(root)
+    root.protocol('WM_DELETE_WINDOW', root.quit)
+    root.mainloop()
+
+if __name__ == '__main__':
+    main()