Matheus Soares da Silva wrote:
> Hello, I would like to be able to get information from a Tkinter canvas
> object. (color, width, tags, root points, etc),
>
> I wrote the following function that, with a canvas bind, returns me the
> widget that has been clicked on, the widget is returned as a tuple by the
> find_overlapping method.
>
> # detecting click
> def Hasclicked(e):
> global obj
> global lastClick
> lastClick = [e.x, e.y]
> obj = e.widget.find_overlapping(e.x, e.y, e.x, e.y)
>
> So, there's any method I can use on 'obj' to get the attributes?
obj is a tuple of ids. You can use canvas.itemcget(id, attribute) to explore
the properties of the underlying objects
To get (for example) their fill-color:
for id in e.widget.find_overlapping(e.x, e.y, e.x, e.y):
print canvas.itemcget(id, "fill")
A complete example:
from __future__ import division
import Tkinter as tk
from math import cos, sin, pi
WIDTH = 640
HEIGHT = 480
root = tk.Tk()
canvas = tk.Canvas(root, width=WIDTH, height=HEIGHT)
canvas.pack()
var = tk.StringVar()
label = tk.Label(root, textvariable=var)
label.pack()
def canvas_click(event):
x, y = event.x, event.y
ids = canvas.find_overlapping(x, y, x, y)
clicked_colors = ", ".join(canvas.itemcget(id, "fill") for id in ids)
var.set(clicked_colors)
RADIUS = 100
R = 80
CX = WIDTH // 2
CY = HEIGHT // 2
phi = pi/2 # 90 degree
for color in "red", "green", "blue":
x = int(CX + R*cos(phi))
y = int(CY - R*sin(phi))
phi += pi*2/3 # 120 degree
canvas.create_oval(x-RADIUS, y-RADIUS, x+RADIUS, y+RADIUS, fill=color)
canvas.bind("<Button-1>", canvas_click)
root.mainloop()
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