Matt's examples

Demo/tkinter/matt/canvas-moving-w-mouse.py

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+from Tkinter import *
+
+# this file demonstrates the movement of a single canvas item under mouse control
+
+class Test(Frame):
+    ###################################################################
+    ###### Event callbacks for THE CANVAS (not the stuff drawn on it)
+    ###################################################################
+    def mouseDown(self, event):
+	# remember where the mouse went down
+	self.lastx = event.x
+	self.lasty = event.y
+		
+	
+    def mouseMove(self, event):
+	# whatever the mouse is over gets tagged as "current" for free by tk.
+	self.draw.move("current", event.x - self.lastx, event.y - self.lasty)
+	self.lastx = event.x
+	self.lasty = event.y
+
+    ###################################################################
+    ###### Event callbacks for canvas ITEMS (stuff drawn on the canvas)
+    ###################################################################
+    def mouseEnter(self, event):
+        # the "current" tag is applied to the object the cursor is over.
+	# this happens automatically.
+	self.draw.itemconfig("current", {"fill" : "red"})
+	
+    def mouseLeave(self, event):
+	# the "current" tag is applied to the object the cursor is over.
+	# this happens automatically.
+	self.draw.itemconfig("current", {"fill" : "blue"})
+
+
+    def createWidgets(self):
+	self.QUIT = Button(self, {'text': 'QUIT', 
+				  'fg': 'red', 
+				  'command': self.quit})
+	self.QUIT.pack({'side': 'left', 'fill': 'both'})	
+	self.draw = Canvas(self, {"width" : "5i", "height" : "5i"})
+	self.draw.pack({'side': 'left'})
+	
+
+	fred = self.draw.create_oval(0, 0, 20, 20,
+				     {"fill" : "green", "tag" : "selected"})
+
+	self.draw.bind(fred, "<Any-Enter>", self.mouseEnter)
+	self.draw.bind(fred, "<Any-Leave>", self.mouseLeave)
+	    
+
+	Widget.bind(self.draw, "<1>", self.mouseDown)
+	Widget.bind(self.draw, "<B1-Motion>", self.mouseMove)
+
+    def __init__(self, master=None):
+	Frame.__init__(self, master)
+	Pack.config(self)
+	self.createWidgets()
+
+test = Test()
+test.mainloop()