Matt's examples

Demo/tkinter/matt/canvas-mult-item-sel.py

@@ -0,0 +1,85 @@
+from Tkinter import *
+
+# allows moving dots with multiple selection. 
+
+SELECTED_COLOR = "red"
+UNSELECTED_COLOR = "blue"
+
+class Test(Frame):
+    ###################################################################
+    ###### Event callbacks for THE CANVAS (not the stuff drawn on it)
+    ###################################################################
+    def mouseDown(self, event):
+	# see if we're inside a dot. If we are, it
+	# gets tagged as "current" for free by tk.
+
+	if not event.widget.find_withtag("current"):
+	    # we clicked outside of all dots on the canvas. unselect all.
+	    
+	    # re-color everything back to an unselected color
+	    self.draw.itemconfig("selected", {"fill" : UNSELECTED_COLOR})
+	    # unselect everything
+	    self.draw.dtag("selected")
+	else:
+	    # mark as "selected" the thing the cursor is under
+	    self.draw.addtag("selected", "withtag", "current")
+	    # color it as selected
+	    self.draw.itemconfig("selected", {"fill": SELECTED_COLOR})
+
+	self.lastx = event.x
+	self.lasty = event.y
+		
+	
+    def mouseMove(self, event):
+	self.draw.move("selected", event.x - self.lastx, event.y - self.lasty)
+	self.lastx = event.x
+	self.lasty = event.y
+
+    def makeNewDot(self):
+	# create a dot, and mark it as current
+	fred = self.draw.create_oval(0, 0, 20, 20, 
+				     {"fill" : SELECTED_COLOR, "tag" : "current"})
+	# and make it selected
+	self.draw.addtag("selected", "withtag", "current")
+	
+    def createWidgets(self):
+	self.QUIT = Button(self, {'text': 'QUIT', 
+				  'fg': 'red', 
+				  'command': self.quit})
+
+	################
+	# make the canvas and bind some behavior to it
+	################
+	self.draw = Canvas(self, {"width" : "5i", "height" : "5i"})
+	Widget.bind(self.draw, "<1>", self.mouseDown)
+	Widget.bind(self.draw, "<B1-Motion>", self.mouseMove)
+
+
+	# and other things.....
+	self.button = Button(self, {"text" : "make a new dot",
+				    "command" : self.makeNewDot,
+				    "fg" : "blue"})
+
+	self.label = Message(self,
+			     {"width" : "5i", 
+			      "text" : SELECTED_COLOR + " dots are selected and can be dragged.\n" +
+   			               UNSELECTED_COLOR + " are not selected.\n" +
+				             "Click in a dot to select it.\n" +
+				             "Click on empty space to deselect all dots." })
+
+	self.QUIT.pack({'side': 'bottom', 'fill': 'both'})	
+	self.label.pack({"side" : "bottom", "fill" : "x", "expand" : 1})
+	self.button.pack({"side" : "bottom", "fill" : "x"})
+	self.draw.pack({'side': 'left'})
+	
+
+    def __init__(self, master=None):
+	Frame.__init__(self, master)
+	Pack.config(self)
+	self.createWidgets()
+
+test = Test()
+test.mainloop()
+
+
+