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#/*
#Python and Tkinter Programming
#John E. Grayson
#ISBN: 1884777813
#Publisher: Manning
#*/
from Tkinter import *
import thread, time
trace = 0
class CanvasEventsDemo:
def __init__(self, parent=None):
canvas = Canvas(width=300, height=300, bg='beige')
canvas.pack()
canvas.bind('<ButtonPress-1>', self.onStart) # click
canvas.bind('<B1-Motion>', self.onGrow) # and drag
canvas.bind('<Double-1>', self.onClear) # delete all
canvas.bind('<ButtonPress-3>', self.onMove) # move latest
self.canvas = canvas
self.drawn = None
self.kinds = [canvas.create_oval, canvas.create_rectangle]
def onStart(self, event):
self.shape = self.kinds[0]
self.kinds = self.kinds[1:] + self.kinds[:1] # start dragout
self.start = event
self.drawn = None
def onGrow(self, event): # delete and redraw
canvas = event.widget
if self.drawn: canvas.delete(self.drawn)
objectId = self.shape(self.start.x, self.start.y, event.x, event.y)
if trace: print objectId
self.drawn = objectId
def onClear(self, event):
event.widget.delete('all') # use tag all
def onMove(self, event):
if self.drawn: # move to click spot
if trace: print self.drawn
canvas = event.widget
diffX, diffY = (event.x - self.start.x), (event.y - self.start.y)
canvas.move(self.drawn, diffX, diffY)
self.start = event
class CanvasEventsDemoTags(CanvasEventsDemo):
def __init__(self, parent=None):
CanvasEventsDemo.__init__(self, parent)
self.canvas.create_text(75, 8, text='Press o and r to move shapes')
self.canvas.master.bind('<KeyPress-o>', self.onMoveOvals)
self.canvas.master.bind('<KeyPress-r>', self.onMoveRectangles)
self.kinds = self.create_oval_tagged, self.create_rectangle_tagged
def create_oval_tagged(self, x1, y1, x2, y2):
objectId = self.canvas.create_oval(x1, y1, x2, y2)
self.canvas.itemconfig(objectId, tag='ovals', fill='blue')
return objectId
def create_rectangle_tagged(self, x1, y1, x2, y2):
objectId = self.canvas.create_rectangle(x1, y1, x2, y2)
self.canvas.itemconfig(objectId, tag='rectangles', fill='red')
return objectId
def onMoveOvals(self, event):
print 'moving ovals'
self.moveInSquares(tag='ovals') # move all tagged ovals
def onMoveRectangles(self, event):
print 'moving rectangles'
self.moveInSquares(tag='rectangles')
def moveInSquares(self, tag): # 5 reps of 4 times per sec
for i in range(5):
for (diffx, diffy) in [(+20, 0), (0, +20), (-20, 0), (0, -20)]:
self.canvas.move(tag, diffx, diffy)
self.canvas.update() # force screen redraw/update
time.sleep(0.25) # pause, but don't block gui
class CanvasEventsDemoThread(CanvasEventsDemoTags):
def moveEm(self, tag):
for i in range(5):
for (diffx, diffy) in [(+20, 0), (0, +20), (-20, 0), (0, -20)]:
self.canvas.move(tag, diffx, diffy)
time.sleep(0.25) # pause this thread only
def moveInSquares(self, tag):
thread.start_new_thread(self.moveEm, (tag,))
if __name__ == '__main__':
CanvasEventsDemoThread()
mainloop()
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