We Keep Coding

Python - Tkinter event_generate not detected by bind

I have two classes (one called 'Point' one called 'PointConector'), both of which inherits 'Frame' (Im not sure If I need to but was seeing if it helped)
When I move the Point (mouse Enter/Leave) and drag the point around, I want to fire off an event for 'PointConnector' (which is a line thats joins the twp points) to pick up the event and redraw the line with the new position of the point.
If I use the event_generate from the canvas object and bind also from the canvas object then the event is picked up, but the object that is passed is the canvas object, not the Point object.
If I fire the event_generate from the Point object (which is inherited from Frame) then the event is ignored
I need the bind event to have the Widget field set to the 'Point' that generated the event. ie I need to have a handle to the point that fired the event. So the Field 'Widget' in the event should be the Point object that is being handled, not the canvas.
from tkinter import Tk, Canvas,Frame
class pointConnector(Frame):
point1 = None
point2 = None
connector = None
def __init__(self,canvas, point1,point2):
super(pointConnector,self).__init__(canvas)
self.point1 = point1
self.point2 = point2
self.canvas = canvas
p1 = self.canvas.translatePoint((self.point1.x,self.point1.y))
p2 = self.canvas.translatePoint((self.point2.x,self.point2.y))
self.connector = canvas.create_line(p1[0], p1[1], p2[0], p2[1],fill='red',state="hidden", width =2)
self.canvas.bind("<<foo>>",self.dummy)
def dummy(self,event):
print("Virtual Event Data: {}".format(event))
def show(self):
self.canvas.itemconfig(self.connector,state="normal")
class screen(Canvas):
width =0
height=0
cY = 0
cX = 0
items =[]
dragItem = None
mouseOverItem = None
def setScreenSize(self,width,height):
self.height = height
self.width = width
self.cX = int(width/2)
self.cY = int(height/2)
def __init__(self,root, unit,width,height):
super(screen,self).__init__(root,width=width,height=height)
self.root = root
self.width = width
self.height = height
self.setScreenSize(width,height)
self.tag_bind('DRAG_OBJECT','<ButtonPress-1>',self.onStartDrag)
self.tag_bind('DRAG_OBJECT','<ButtonRelease-1>',self.onEndDrag)
self.tag_bind('DRAG_OBJECT','<B1-Motion>',self.onDrag)
self.bind("<Configure>", self.configure)
def addObject(self,object):
self.items.append(object)
def findObject(self,tags):
for item in self.items:
if str(item.id) in tags:
return item
return None
def onStartDrag(self,event):
self.dragItem= self.find_closest(event.x,event.y)
wt = self.gettags(self.dragItem)
self.dragItem = self.findObject(wt)
def onEndDrag(self,event):
self.dragItem = None
def onDrag(self,event):
self.dragItem.move(event.x,event.y)
def draw(self):
# Draw array of items
for o in self.items:
o.show()
def translateX(self,x):
return (x + self.cX)
def translateY(self,y):
return (y + self.cY)
def translatePoint(self,pointxy):
return (self.translateX(pointxy[0]),self.translateY(pointxy[1]))
class point(Frame):
state = "normal"
x : int
y : int
def setPoint(self,x,y):
self.x = x
self.y = y
def __init__(self,canvas,x,y,radius,ObjectName):
super(point,self).__init__(canvas)
self.x = x
self.y = y
self.radius = radius
self.canvas = canvas
self.ObjectName= ObjectName
self.id = None
self.create_point()
def create_point(self):
x = self.canvas.translateX(self.x)
y = self.canvas.translateY(self.y)
self.circle = self.canvas.create_oval(x-self.radius,y-self.radius,x+self.radius,y+self.radius,state=self.state,fill='yellow')
self.text = self.canvas.create_text(x,y,text=self.ObjectName,state=self.state )
self.canvas.itemconfig(self.circle, tags=({"type":"POINT", "name":self.ObjectName},"DRAG_OBJECT"))
self.canvas.itemconfig(self.text, tags=({"type":"POINT", "name":self.ObjectName},"DRAG_OBJECT"))
self.id = {"type":"POINT", "name":self.ObjectName}
def show(self):
newX = self.canvas.translateX(self.x)
newY = self.canvas.translateY(self.y)
self.canvas.itemconfig(self.circle,state='normal')
self.canvas.coords(self.circle,(newX-self.radius,newY-self.radius,newX + self.radius, newY + self.radius))
self.canvas.coords(self.text,(newX,newY))
self.canvas.itemconfig(self.text,state='normal')
self.canvas.tag_raise(self.circle)
self.canvas.tag_raise(self.text)
def hide(self):
self.canvas.itemconfig(self.circle,state='hidden')
self.canvas.itemconfig(self.text,state='hidden')
def move (self,x,y):
delta_x = x- (self.x + self.canvas.cX)
delta_y = y- (self.y + self.canvas.cY)
self.canvas.move(self.circle,delta_x,delta_y)
self.canvas.move(self.text,delta_x,delta_y)
self.x = x - self.canvas.cX
self.y = y - self.canvas.cY
## If I use the canvas object (that is passed in) then the Point object picks up the event, but then I cant tell which 'Point' is begin dragged
#self.canvas.event_generate("<<foo>>",x=self.x,y=self.y,when='now')
## If I generate the event from the Point Object then the Event is lost
self.event_generate("<<foo>>",x=self.x,y=self.y,when='tail')
self.update()
# Start of program
print("Start --->")
tk = Tk()
mainScreen = screen(tk,20,700,700)
mainScreen.pack(fill="both",expand=1)
# Add Point A
pointA = point(mainScreen,0,0,10,"A",)
mainScreen.addObject(pointA)
# Add Point B
pointB = point(mainScreen,20,20,10,"B")
mainScreen.addObject(pointB)
LineA = pointConnector(mainScreen,pointA,pointB)
mainScreen.addObject(LineA)
mainScreen.draw()
tk.mainloop()

tkinter - problem with a coloring a rectangle in a grid made out of rectangles

I am trying to write a pathfinding algorithm in python. The user is supposed to select a starting point by hovering the mouse of a field and pressing s. The field should now change the color.
However, I can't figure out what is wrong with my code. I am only able to color to color the fields from top left corner to the bottom right corner. In the code, Im printing out the objectID in console, which shows that there is maybe something wrong with the way of how I created the rectangles.
I'm creating the rectangles in the draw_grid method in the Window class and coloring the fields in the select_start_node method.
import tkinter as tk
class Window:
def __init__(self):
self.height = 600
self.width = 600
self.grid_list = {x for x in range(0, 600)}
self.grid = []
self.grid_dict = {}
self.root = tk.Tk()
self.root.geometry("600x600")
self.root.resizable(False, False)
self.canvas = tk.Canvas(self.root, width=self.width,
height=self.height, background="white")
self.canvas.bind("s", self.select_start_node)
self.canvas.bind("<1>", lambda event:
self.canvas.focus_set())
def draw_grid(self):
print(self.grid)
for x in self.grid_list:
if x % 30 == 0:
self.grid.append(x)
else:
pass
print(self.grid)
for x in self.grid:
for y in self.grid:
print(x, y+30)
rec = self.canvas.create_rectangle(x, x, y+30, y+30)
self.canvas.pack()
def select_start_node(self, event):
print(event.x, event.y)
x = self.canvas.canvasx(event.x)
y = self.canvas.canvasy(event.y)
item = self.canvas.find_closest(x, y)
p = self.canvas.coords(item)
print(item)
print(p)
self.canvas.create_rectangle(p[0], p[0], p[0]+30, p[0]+30, fill="red")
def main():
node_list = []
cord_list = []
window = Window()
window.draw_grid()
window.root.mainloop()
if __name__ == "__main__":
main()

I don't know the entire design of you game, but suggest that you do things differently with respect to the grid of rectangles. In the code below self.grid is a 2-dimensional list-of-lists and each entry is a Canvas rectangle object. This make selecting and changing one of them relatively each because canvas.find_closest(x, y) will give you the object id of the associated rectangle object directly, which makes changing its fill color trivial.
Because of that, I also changed it so you can just click on one of the rectangles to change it instead of moving the mouse cursor and then pressing a key.
Also note that I also got rid of most those hardcoded numerical constants you were using all over the place, which makes the code more flexible in case you decide to change one of them at a later time.
import tkinter as tk
class Window:
def __init__(self):
self.cell_size = 30
self.height = 600
self.width = 600
self.hz_cells = self.width // self.cell_size # Number of horizontal cells.
self.vt_cells = self.height // self.cell_size # Number of vertical cells.
# Preallocate 2D grid (list-of-lists).
self.grid = [[None for _ in range(self.hz_cells)]
for _ in range(self.vt_cells)]
self.root = tk.Tk()
self.root.geometry("%sx%s" % (self.width, self.height))
self.root.resizable(False, False)
self.canvas = tk.Canvas(self.root, width=self.width,
height=self.height, background="white")
self.canvas.pack()
self.canvas.bind("<1>", self.select_start_node)
# You can still do it this way if you want.
# self.canvas.bind("s", self.select_start_node)
# self.canvas.bind("<1>", lambda event: self.canvas.focus_set())
def draw_grid(self):
""" Fill Canvas with a grid of white rectangles. """
for i in range(self.hz_cells):
x = i * self.cell_size
for j in range(self.vt_cells):
y = j * self.cell_size
self.grid[i][j] = self.canvas.create_rectangle(
x, y, x+self.cell_size, y+self.cell_size, fill="white")
def select_start_node(self, event):
""" Change the color of the rectangle closest to x, y of event. """
x = self.canvas.canvasx(event.x)
y = self.canvas.canvasy(event.y)
selected_rect = self.canvas.find_closest(x, y)
if selected_rect:
self.canvas.itemconfigure(selected_rect, fill="red") # Change color.
def main():
node_list = []
cord_list = []
window = Window()
window.draw_grid()
window.root.mainloop()
if __name__ == "__main__":
main()

Tkinter Button not registering click

I have the following tkinter button class
import tkinter as tk
class Button(GraphicsObject):
"""A button is a labeled rectangle in a window.
It is activated or deactivated with the activate()
and deactivate() methods. The clicked(p) method
returns true if the button is active and p is inside it."""
def __init__(self, p, width, height, label):
""" Creates a rectangular button, eg: qb = Button(myWin, Point(30,25), 20, 10, 'Quit') """
GraphicsObject.__init__(self, [])
self.anchor = p.clone()
w,h = width/2.0, height/2.0
self.x, self.y = p.getX(), p.getY()
self.xmax, self.xmin = self.x+w, self.x-w
self.ymax, self.ymin = self.y+h, self.y-h
p1 = Point(self.xmin, self.ymin)
p2 = Point(self.xmax, self.ymax)
self.width = width
self.height = height
self.rect = Rectangle(p1,p2)
self.label = label
self.fill = "white"
self.color = "black"
self.font = DEFAULT_CONFIG['font']
self.activate()
def _draw(self, canvas, options):
p = self.anchor
x,y = canvas.toScreen(p.x,p.y)
#frm = tk.Frame(canvas.master,height = self.height, width = self.width,)
# frm.pack_propagate(0)
#frm.pack()
self.button = tk.Button(canvas.master,
height = self.height,
width = self.width,
text = self.label,
bg = self.fill,
fg = self.color,
font=self.font)
self.button.place(x = self.x, y = self.y, height =self.height, width = self.width)
#self.setFill(self.fill)
self.button.focus_set()
#return canvas.create_window(x,y,window=self.button)
def clicked(self, p):
""" RETURNS true if button active and p is inside"""
return self.active and \
self.xmin <= p.getX() <= self.xmax and \
self.ymin <= p.getY() <= self.ymax
def getLabel(self):
"""RETURNS the label string of this button."""
return self.label.getText()
def setColor(self, color):
self.color = color
def setFill(self, color):
self.fill = color
def activate(self):
"""Sets this button to 'active'."""
self.color = 'black'
self.rect.setWidth(2)
self.active = 1
def deactivate(self):
"""Sets this button to 'inactive'."""
self.color = 'darkgrey'
self.rect.setWidth(1)
self.active = 0
I first decided to test it out by calling the method clicked in the following loop:
sign_in_button = Button(Point(237.5,300),80,40,'Sign In')
sign_in_button.draw(login_page)
click_point = login_page.getMouse()
clicked = sign_in_button.clicked(click_point)
print(clicked)
while(clicked == False):
click_point = login_page.getMouse()
clicked = sign_in_button.clicked(click_point)
print(clicked)
print("clicked == True")
When I run my program, the button appears correctly on the window and as long as I don't click inside the button it does register a clicked value of False. However, when I click on the button, nothing happens. Both print(clicked) and print(clicked == True) never run when clicked should have a value of True. Do I need to modify my class or did I just forget to include something when I try to create the Button?

How may I reset the view of a canvas in tkinter?

When I draw a rectangle in the canvas I know its coordinates, absolute (canvasx(), canvasy()) and relative (the ones that I have passed).
Then, I may be able to move the canvas using the canvas scan_mark() and scan_dragto() methods.
How may I return to the original position (before one or more of these scan_mark()/scan_dragto() calls) in order to re-center the rectangle of which the user might even have lost the position?
Is there any reset view command/method? How may I keep track of the change that has occurred?

The Tkinter documentation I've seen doesn't seem to mention this, but the underlying Tk Canvas xview/yview methods can be called with no parameter to get the current scroll position (actually, as a tuple of two elements, the second not being of any use to you). So, the following should work (not tested):
Save position:
origX = yourcanvas.xview()[0]
origY = yourcanvas.yview()[0]
Restore position:
yourcanvas.xview_moveto(origX)
yourcanvas.yview_moveto(origY)

As in the previous comment #jasonharper, his suggestion worked. For others who might have the same problem I attach a working example even though it has not been cleaned so well to be proud of, it may give you way to see how zoom in and out, view drag and reset might work.
import tkinter as tk
import tkinter.ttk as ttk
class GriddedMazeCanvas(tk.Canvas):
def almost_centered(self, cols, rows):
width = int(self['width'])
height = int(self['height'])
cell_dim = self.settings['cell_dim']
rows = rows % height
cols = cols % width
w = cols * cell_dim
h = rows * cell_dim
if self.zoom < 0:
raise ValueError('zoom is negative:', self.zoom)
zoom = self.zoom // 2 + 1
if self.drawn() and 1 != zoom:
w *= zoom
h *= zoom
h_shift = (width - w) // 2
v_shift = (height - h) // 2
return [h_shift, v_shift,
h_shift + w, v_shift + h]
def __init__(self, *args, **kwargs):
if 'settings' not in kwargs:
raise ValueError("'settings' not passed.")
settings = kwargs['settings']
del kwargs['settings']
super().__init__(*args, **kwargs)
self.config(highlightthickness=0)
self.settings = settings
self.bind_events()
def draw_maze(self, cols, rows):
self.cols = cols
self.rows = rows
if self.not_drawn():
self.cells = {}
self.cell_dim = self.settings['cell_dim']
self.border_thickness = self.settings['border_thickness']
self.zoom = 0
self.delete(tk.ALL)
maze, coords = self._draw_maze(cols, rows, fix=False)
lines = self._draw_grid(coords)
return maze, lines
def _draw_maze(self, cols, rows, fix=True):
data = self.settings
to_max = data['to_max']
border_thickness = data['border_thickness']
poligon_color = data['poligon_color']
poligon_border_color = data['poligon_border_color']
coords = self.almost_centered(cols, rows)
if fix:
# Fix for the disappearing NW borders
if to_max == cols:
coords[0] += 1
if to_max == rows:
coords[1] += 1
maze = self.create_rectangle(*coords,
fill=poligon_color,
outline=poligon_border_color,
width=border_thickness,
tag='maze')
return maze, coords
def _draw_grid(self, coords):
data = self.settings
poligon_border_color = data['poligon_border_color']
cell_dim = data['cell_dim']
if coords is None:
if self.not_drawn():
raise ValueError('The maze is still uninitialized.')
x1, y1, x2, y2 = self.almost_centered(self.cols, self.rows)
else:
x1, y1, x2, y2 = coords
if self.drawn() and 0 != self.zoom:
if self.zoom < 0:
self.zoom = 0
print('no zooming at negative values.')
else:
zoom = self.zoom // 2 + 1
cell_dim *= zoom
lines = []
for i, x in enumerate(range(x1, x2, cell_dim)):
line = self.create_line(x, y1, x, y2,
fill=poligon_border_color,
tags=('grid', 'grid_hl_{}'.format(i)))
lines.append(line)
for i, y in enumerate(range(y1, y2, cell_dim)):
line = self.create_line(x1, y, x2, y,
fill=poligon_border_color,
tags=('grid', 'grid_vl_{}'.format(i)))
lines.append(line)
return lines
def drawn(self):
return hasattr(self, 'cells')
def not_drawn(self):
return not self.drawn()
def bind_events(self):
self.bind('<Button-4>', self.onZoomIn)
self.bind('<Button-5>', self.onZoomOut)
self.bind('<ButtonPress-1>', self.onScrollStart)
self.bind('<B1-Motion>', self.onScrollMove)
self.tag_bind('maze', '<ButtonPress-3>', self.onMouseRight)
def onScrollStart(self, event):
print(event.x, event.y, self.canvasx(event.x), self.canvasy(event.y))
self.scan_mark(event.x, event.y)
def onMouseRight(self, event):
col, row = self.get_pos(event)
print('zoom, col, row:', self.zoom, col, row)
def onScrollMove(self, event):
delta = event.x, event.y
self.scan_dragto(*delta, gain=1)
def onZoomIn(self, event):
if self.not_drawn():
return
max_zoom = 16
self.zoom += 2
if self.zoom > max_zoom:
print("Can't go beyond", max_zoom)
self.zoom = max_zoom
return
print('Zooming in.', event.num, event.x, event.y, self.zoom)
self.draw_maze(self.cols, self.rows)
def onZoomOut(self, event):
if self.not_drawn():
return
self.zoom -= 2
if self.zoom < 0:
print("Can't go below zero.")
self.zoom = 0
return
print('Zooming out.', event.num, event.x, event.y, self.zoom)
self.draw_maze(self.cols, self.rows)
def get_pos(self, event):
x, y = event.x, event.y
cols, rows = self.cols, self.rows
cell_dim, zoom = self.cell_dim, self.zoom
x1, y1, x2, y2 = self.almost_centered(cols, rows)
if not (x1 <= x <= x2 and y1 <= y <= y2):
print('Here we are out of bounds.')
return None, None
scale = (zoom // 2 + 1) * cell_dim
col = (x - x1) // scale
row = (y - y1) // scale
return col, row
class CanvasButton(ttk.Button):
def freeze_origin(self):
if not hasattr(self, 'origin'):
canvas = self.canvas
self.origin = canvas.xview()[0], canvas.yview()[0]
def reset(self):
canvas = self.canvas
x, y = self.origin
canvas.yview_moveto(x)
canvas.xview_moveto(y)
def __init__(self, *args, **kwargs):
if not 'canvas' in kwargs:
raise ValueError("'canvas' not passed.")
canvas = kwargs['canvas']
del kwargs['canvas']
super().__init__(*args, **kwargs)
self.config(command=self.reset)
self.canvas = canvas
root = tk.Tk()
settings = {'cell_dim': 3,
'to_max': 200,
'border_thickness': 1,
'poligon_color': '#F7F37E',
'poligon_border_color': '#AC5D33'}
frame = ttk.Frame(root)
canvas = GriddedMazeCanvas(frame,
settings=settings,
width=640,
height=480)
button = CanvasButton(frame, text='Reset', canvas=canvas)
button.freeze_origin()
canvas.draw_maze(20, 10)
canvas.grid(row=0, column=0, sticky=tk.NSEW)
button.grid(row=1, column=0, sticky=tk.EW)
frame.rowconfigure(0, weight=1)
frame.grid()
root.mainloop()
Tested with Python 3.4 on latest Ubuntu 16.10
(Events: MouseLeft, Mouseright, MouseWheel, ButtonPress)
HTH

How to stop other processes or finish processes in Python / Tkinter program

I have been drawing some graphics with a Python / Tkinter program. The program has a main menu with menu items for drawing different figures. It works quite well but I came up against a problem. If the program is part way through drawing one figure and the user clicks to draw a second figure then the program draws the second figure, but when it has finished drawing the second figure it goes back and finishes drawing the first figure. What I want it to do is stop drawing the first figure and not go back to drawing the first figure even when the second figure has finished drawing. I created an simpler example program to demonstrate the scenario. To see the problem in this program click "Draw -> Red" and then click "Draw -> Blue" before the red has finished drawing. How do I get the program to abort any previous drawing? Here is the example program:
from tkinter import *
import random
import math
def line(canvas, w, h, p, i):
x0 = random.randrange(0, w)
y0 = random.randrange(0, h)
x1 = random.randrange(0, w)
y1 = random.randrange(0, h)
canvas.create_line(x0, y0, x1, y1, fill=p.col(i))
class Color:
def __init__(self, r, g, b):
self.red = r
self.gre = g
self.blu = b
def hexVal(self, v):
return (hex(v)[2:]).zfill(2)
def str(self):
return "#" + self.hexVal(self.red) + self.hexVal(self.gre) + self.hexVal(self.blu)
class Palette:
def __init__(self, n0, y):
self.colors = []
self.n = n0
self.m = 0
if y == "red":
self.red()
elif y == "blue":
self.blue()
def add(self, c):
self.colors.append(c)
self.m += 1
def red(self):
self.add(Color(127, 0, 0))
self.add(Color(255, 127, 0))
def blue(self):
self.add(Color(0, 0, 127))
self.add(Color(0, 127, 255))
def col(self, i):
k = i % (self.n*self.m)
z = k // self.n
j = k % self.n
c0 = self.colors[z]
c1 = self.colors[(z + 1) % self.m]
t0 = (self.n - j)/self.n
t1 = j/self.n
r = int(math.floor(c0.red*t0 + c1.red*t1))
g = int(math.floor(c0.gre*t0 + c1.gre*t1))
b = int(math.floor(c0.blu*t0 + c1.blu*t1))
c = Color(r, g, b)
return c.str()
def upd(canvas):
try:
canvas.update()
return True
except TclError:
return False
def tryLine(canvas, w, h, p, i, d):
try:
line(canvas, w, h, p, i)
if i % d == 0:
upd(canvas)
return True
except TclError:
return False
class MenuFrame(Frame):
def __init__(self, parent):
Frame.__init__(self, parent)
self.parent = parent
self.initUI()
def initUI(self):
self.WIDTH = 800
self.HEIGHT = 800
self.canvas = Canvas(self.parent, width=self.WIDTH, height=self.HEIGHT)
self.pack(side=BOTTOM)
self.canvas.pack(side=TOP, fill=BOTH, expand=1)
self.parent.title("Line Test")
menubar = Menu(self.parent)
self.parent.config(menu=menubar)
self.parent.protocol('WM_DELETE_WINDOW', self.onExit)
menu = Menu(menubar)
menu.add_command(label="Red", command=self.onRed)
menu.add_command(label="Blue", command=self.onBlue)
menu.add_command(label="Exit", command=self.onExit)
menubar.add_cascade(label="Draw", menu=menu)
self.pRed = Palette(256, "red")
self.pBlue = Palette(256, "blue")
def onRed(self):
# How to abort here any processes currently running?
self.canvas.delete("all")
for i in range(0, 7000):
tryLine(self.canvas, self.WIDTH, self.HEIGHT, self.pRed, i, 100)
upd(self.canvas)
def onBlue(self):
# How to abort here any processes currently running?
self.canvas.delete("all")
for i in range(0, 7000):
tryLine(self.canvas, self.WIDTH, self.HEIGHT, self.pBlue, i, 100)
upd(self.canvas)
def onExit(self):
self.canvas.delete("all")
self.parent.destroy()
def main():
root = Tk()
frame = MenuFrame(root)
root.mainloop()
if __name__ == '__main__':
main()

That's the simple example? ;)
You can add a variable that tracks the currently selected method, then check if that variable exists before completing the for loop. Here's an even simpler example:
class Example(Frame):
def __init__(self, parent):
Frame.__init__(self, parent)
Button(self, text='Task A', command=self._a).pack()
Button(self, text='Task B', command=self._b).pack()
self.current_task = None # this var will hold the current task (red, blue, etc)
def _a(self):
self.current_task = 'a' # set the current task
for i in range(1000):
if self.current_task == 'a': # only continue this loop if its the current task
print('a')
self.update()
def _b(self):
self.current_task = 'b'
for i in range(1000):
if self.current_task == 'b':
print('b')
self.update()
root = Tk()
Example(root).pack()
root.mainloop()
Let me know if that doesn't make sense or doesn't work out for you.