Demo/tkinter/matt/canvas-gridding.py

   1 from Tkinter import *
   2
   3 # this is the same as simple-demo-1.py, but uses
   4 # subclassing.
   5 # note that there is no explicit call to start Tk.
   6 # Tkinter is smart enough to start the system if it's not already going.
   7
   8 class Test(Frame):
   9     def printit(self):
  10         print "hi"
  11
  12     def createWidgets(self):
  13         self.QUIT = Button(self, text='QUIT',
  14                                   background='red',
  15                                   foreground='white',
  16                                   height=3,
  17                                   command=self.quit)
  18         self.QUIT.pack(side=BOTTOM, fill=BOTH)
  19
  20         self.canvasObject = Canvas(self, width="5i", height="5i")
  21         self.canvasObject.pack(side=LEFT)
  22
  23     def mouseDown(self, event):
  24         # canvas x and y take the screen coords from the event and translate
  25         # them into the coordinate system of the canvas object
  26         self.startx = self.canvasObject.canvasx(event.x, self.griddingSize)
  27         self.starty = self.canvasObject.canvasy(event.y, self.griddingSize)
  28
  29     def mouseMotion(self, event):
  30         # canvas x and y take the screen coords from the event and translate
  31         # them into the coordinate system of the canvas object
  32         x = self.canvasObject.canvasx(event.x, self.griddingSize)
  33         y = self.canvasObject.canvasy(event.y, self.griddingSize)
  34
  35         if (self.startx != event.x)  and (self.starty != event.y) :
  36             self.canvasObject.delete(self.rubberbandBox)
  37             self.rubberbandBox = self.canvasObject.create_rectangle(
  38                 self.startx, self.starty, x, y)
  39             # this flushes the output, making sure that
  40             # the rectangle makes it to the screen
  41             # before the next event is handled
  42             self.update_idletasks()
  43
  44     def __init__(self, master=None):
  45         Frame.__init__(self, master)
  46         Pack.config(self)
  47         self.createWidgets()
  48
  49         # this is a "tagOrId" for the rectangle we draw on the canvas
  50         self.rubberbandBox = None
  51
  52         # this is the size of the gridding squares
  53         self.griddingSize = 50
  54
  55         Widget.bind(self.canvasObject, "<Button-1>", self.mouseDown)
  56         Widget.bind(self.canvasObject, "<Button1-Motion>", self.mouseMotion)
  57
  58
  59 test = Test()
  60
  61 test.mainloop()