Tkinter Tutorial Canvas Chapter (3)

'''Tkinter Tutorial Canvas Chapter (3)'''


'''16. Move item'''


# - *- coding: cp936 -*-


# move specifies x, y at the offset


from Tkinter import *


root = Tk()


# Create a Canvas and set its background color to white

cv = Canvas(root,bg = 'white')

# Create two identical rectangles and compare the movements The difference before and after

rt1 = cv.create_rectangle(
10,10,110,110,
tags = ('r1','r2','r3'))
cv.create_rectangle(
10,10,110,110,
tags = ('r1','r2','r3'))

# Move rt1

cv.move(rt1,20,-10)
cv.pack()
root.mainloop()

# move can specify x, y is a relative offset and can be a negative value


'''17. Delete item'''


# -*- coding: cp936 -*-


# delete deletes the given item

from Tkinter import *
root = Tk()
cv = Canvas(root,bg = 'white')

# creates two rectangles

rt1 = cv.create_rectangle(
10,10,110,110,
tags = ('r1','r2','r3'))
r2 = cv.create_rectangle(
20,20,110,110,
tags = ('s1','s2','s3'))

# Use id to delete rt1


cv.delete(rt1)


# Use tag to delete r2

cv.delete('s1')
cv.pack()
root.mainloop()

# Two methods to delete item(id/tag)


'''18. Zoom item'''


# -*- coding: cp936 -*-


# scale scaling item, calculation formula: (coords - offset)*scale + offset

from Tkinter import *
root = Tk()
cv = Canvas(root,bg = 'white')

# Create two rectangle

rt1 = cv.create_rectangle(
10,10,110,110,
tags = ('r1','r2','r3'))

# Enlarge the y coordinate to the original 2 digits, and the x coordinate value remains unchanged

cv.scale(rt1,0,0,1,2)
cv.pack()
root.mainloop()

# The parameters of scale are (self,xoffset,yoffset,xscale,yscale)


'''19. Binding item and event'''


# -*- coding: cp936 -*-


# Use tag_bind to bind items and events

from Tkinter import *
root = Tk()

# Create a Canvas , set its background color to white

cv = Canvas(root,bg = 'white')

# Create three rectangle

rt1 = cv.create_rectangle(
10,10,110,110,
width = 8,
tags = ('r1','r2','r3'))
def printRect(event):
print 'rectangle'

# Binding item and events

cv.tag_bind(&#39;r1&#39;,&#39;<Button-1>&#39;,printRect)
cv.pack()
root.mainloop()

# The event will only be triggered when the border of the rectangle is clicked


'''20. Add binding Defined event'''


# -*- coding: cp936 -*-


# Use tag_bind to bind item and event, which is inconsistent with the reference test results.

from Tkinter import *
root = Tk()

# Create a Canvas and set its background color to white

cv = Canvas(root,bg = 'white')

# Create three rectangles

rt1 = cv.create_rectangle(
10,10,110,110,
width = 8,
tags = ('r1','r2','r3'))
def printRect(event):
print 'rectangle'
def printLine(event):
print 'line'

# Bind item and left click event

cv.tag_bind(&#39;r1&#39;,&#39;<Button-1>&#39;,printRect)

# Binding item and right-click event

cv.tag_bind(&#39;r1&#39;,&#39;<Button-3>&#39;,printLine)
cv.pack()
root.mainloop()

# The event will only be triggered when the border of the rectangle is clicked. The add parameter is not used. The default is to add to this item. A processing function that does not replace the original event function. Example result: responds to both left and right keys


''' 21. Bind new items to existing tags'''


# -*- coding: cp936 -*-


# Use tag_bind to bind items and events. The test results are inconsistent with the reference statement

from Tkinter import *
root = Tk()

# Create a Canvas and set its background color to white


cv = Canvas(root,bg = 'white')


# Create three rectangles

rt1 = cv.create_rectangle(
10,10,110,110,
width = 8,
tags = ('r1','r2','r3'))
def printRect(event):
print 'rectangle'
def printLine(event):
print 'line'

# Bind item and left click event


cv.tag_bind ('r1','',printRect)


# Bind item and right-click event


cv.tag_bind('r1',' ',printLine)


# Create a line and set its tags to 'r1'

cv.create_line(10,200,100,200,width = 5,tags = 'r1')
cv.pack()
root.mainloop()

# After binding the event to tag('r1'), create a new item and specify the tag of the bound event. The newly created item is also bound to the event. This is inconsistent with the reference.

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