Question for loading images in a class/canvas

[Nebulism]

I have been attempting to utilize a draw command script that loads a canvas, and through certain mouse events, draws rectangles. The original code is from http://www.java2s.com/Code/Python/Ev...peoncanvas.htm .

The code itself is:

from Tkinter import *
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)   
        canvas.bind('<B1-Motion>',     self.onGrow)     
        canvas.bind('<Double-1>',      self.onClear)     
        canvas.bind('<ButtonPress-3>', self.onMove)     
        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]      
        self.start = event
        self.drawn = None
    def onGrow(self, event):                           
        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')                     
    def onMove(self, event):
        if self.drawn:                                   
            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

if __name__ == '__main__':
    CanvasEventsDemo()
    mainloop()

Essentially I am looking at setting the background image as a photo using the create_image function. I have gotten it to work in a structure that is not utilizing classes such as this example code:

# Putting a gif image on a canvas with Tkinter
# tested with Python24 by  vegaseat  25jun2005

from Tkinter import *

# create the canvas, size in pixels
canvas = Canvas(width = 300, height = 200, bg = 'yellow')

# pack the canvas into a frame/form
canvas.pack(expand = YES, fill = BOTH)

# load the .gif image file
# put in your own gif file here, may need to add full path
# like 'C:/WINDOWS/Help/Tours/WindowsMediaPlayer/Img/mplogo.gif'
gif1 = PhotoImage(file = 'DrBunsen.gif')

# put gif image on canvas
# pic's upper left corner (NW) on the canvas is at x=50 y=10
canvas.create_image(50, 10, image = gif1, anchor = NW)

# run it ...
mainloop()

I've gotten it to work with a different file of course, however, when I try to implement my image background in the first code all I get is a grey canvas. So without further ado here is my code:

from Tkinter import *
import Image            #PIL
import ImageTk          #PIL
import sys
import getopt
trace = 0 

class CanvasEventsDemo: 
    def __init__(self, parent=NONE):
        canvas = Canvas(width=400,height=400) 
        canvas.pack()
        im = Image.open("C:/Documents and Settings/John Perry/Desktop/GradSchool/Summer 07 python goshen/cd with CT's/patient10/se002.jpg")
        photo = ImageTk.PhotoImage(im)
        item=canvas.create_image(10, 10, image = photo)
        canvas.bind('<ButtonPress-1>', self.onStart)   
        canvas.bind('<B1-Motion>',     self.onGrow)     
        canvas.bind('<Double-1>',      self.onClear)     
        canvas.bind('<ButtonPress-3>', self.onMove)     
        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]      
        self.start = event
        self.drawn = None
    def onGrow(self, event):                           
        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')                     
    def onMove(self, event):
        if self.drawn:                                   
            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

if __name__ == '__main__':
    CanvasEventsDemo()
    mainloop()

Thanks for any help on getting this little issue fixed! Note that the section I'm referring to is around line 12. I just need my jpg or gif loaded as the background.

Thanks,
JP

[bartonc]

To fix line 12, use raw strings for Windows path names (because the "\" has a special purpose in python strings) and use the "\" in literal path names:

#
# Use raw strings #
        im = Image.open(r"C:\Documents and Settings\John Perry\Desktop\GradSchool\Summer 07 python goshen\cd with CT's\patient10\se002.jpg")

or[CODE=python]#
# escape the backslash #
im = Image.open("C:\ \Documents and Settings\\John Perry\\Desktop\ \GradSchool\\Su mmer 07 python goshen\\cd with CT's\\patient10 \\se002.jpg")[/CODE]

[Nebulism]

Hey all,

I implemented the raw string, however, the image will still not display on the canvas at all. It still remains as a white canvas bg with the mouse event functions. Any ideas, or can you try and get it to display an actual jpg, gif, etc image in the canvas to draw shapes over?

Thanks,
JP

[bartonc]

Hey all,

I implemented the raw string, however, the image will still not display on the canvas at all. It still remains as a white canvas bg with the mouse event functions. Any ideas, or can you try and get it to display an actual jpg, gif, etc image in the canvas to draw shapes over?

Thanks,
JP

I'll try to get some time to work on this for you. I'm swamped at the moment.

[bartonc]

I'll try to get some time to work on this for you. I'm swamped at the moment.

In the mean time, have you seen
An Introduction to Tkinter?

[Nebulism]

I solved the issue. I had to reference my class correctly.

here is the fix:

from Tkinter import *
import Tkinter
import Image            #PIL
import ImageTk          #PIL
import sys
import getopt
trace = 0 

class CanvasEventsDemo: 
    def __init__(self, parent=NONE):
        canvas = Canvas(win)
        canvas.pack(fill=BOTH)
        self.img = PhotoImage(file="C:/Documents and Settings/John Perry/Desktop/GradSchool/Summer 07 python goshen/cd with CT's/patient10/se002.gif")
        canvas.config(width=self.img.width(), height=self.img.height())
        canvas.create_image(0,0, image=self.img, anchor=NW)
        canvas.bind('<ButtonPress-1>', self.onStart)   
        canvas.bind('<B1-Motion>',     self.onGrow)     
        canvas.bind('<Double-1>',      self.onClear)     
        canvas.bind('<ButtonPress-3>', self.onMove)     
        self.canvas = canvas
        self.drawn  = None
        self.kinds = [canvas.create_rectangle]
    def onStart(self, event):
        event.widget.delete('all')
        self.canvas.create_image(0,0, image=self.img, anchor=NW)
        self.shape = self.kinds[0]
        self.kinds = self.kinds[1:] + self.kinds[:1]      
        self.start = event
        self.drawn = None
    def onGrow(self, event):                           
        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
        self.xorig=self.start.x
        self.yorig=self.start.y
        self.xfinal=event.x
        self.yfinal=event.y
    def onClear(self, event):
        event.widget.delete('all')
        self.canvas.create_image(0,0, image=self.img, anchor=NW)
    def onMove(self, event):
        if self.drawn:                                   
            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

if __name__ == '__main__':
    win=Tk()
    jop=CanvasEventsDemo()
    mainloop()

JP

[bartonc]

Awesome! Thanks for keeping us up-to-date with you progress.