I feel like this is a little bit complicated or at least I'm confused on it, so I'll try to explain it by rendering the issue. Let me know if the issue isn't clear.
I get the output from my viewing_box through the __init__ method and it shows:
(0, 0, 378, 265)
Which is equivalent to a width of 378 and a height of 265.
When failing, I track the output:
1 false
1 false
here ([0.0, -60.0], [100.0, 40.0]) (0, 60, 378, 325)
The tracking is done in _scan_view with the code:
if not viewable:
current = self.itemcget(item,'tags')
if isinstance(current, tuple):
new = current-('viewable',)
else:
print('here',points, (x1,y1,x2,y2))
new = ''
self.inview_items.discard(item)
So the rectangle stays with width and height of 100, the coords however failing to be the expected ones. While view width and height stays the same and moves correctly in my current understanding. Expected:
if x1 <= point[0] <= x2 and y1 <= point[1] <= y2: and it feels like I've created two coordinate systems but I don't get it. Is someone looking on it and see it immediately?
Full Code:
import tkinter as tk
class InfiniteCanvas(tk.Canvas):
def __init__(self, master, **kwargs):
super().__init__(master, **kwargs)
self.inview_items = set() #in view
self.niview_items = set() #not in view
self._xshifted = 0 #view moved in x direction
self._yshifted = 0 #view moved in y direction
self._multi = 0
self.configure(confine=False,highlightthickness=0,bd=0)
self.bind('<MouseWheel>', self._vscroll)
self.bind('<Shift-MouseWheel>', self._hscroll)
root.bind('<Control-KeyPress>',lambda e:setattr(self,'_multi', 10))
root.bind('<Control-KeyRelease>',lambda e:setattr(self,'_multi', 0))
print(self.viewing_box())
return None
def viewing_box(self):
'returns x1,y1,x2,y2 of the currently visible area'
x1 = 0 - self._xshifted
y1 = 0 - self._yshifted
x2 = self.winfo_reqwidth()-self._xshifted
y2 = self.winfo_reqheight()-self._yshifted
return x1,y1,x2,y2
def _scan_view(self):
x1,y1,x2,y2 = self.viewing_box()
for item in self.find_withtag('viewable'):
#check if one felt over the edge
coords = self.coords(item)
#https://www.geeksforgeeks.org/python-split-tuple-into-groups-of-n/
points = tuple(
coords[x:x + 2] for x in range(0, len(coords), 2))
viewable = False
for point in points:
if x1 <= point[0] <= x2 and y1 <= point[1] <= y2:
#if any point is in viewing box
viewable = True
print(item, 'true')
else:
print(item, 'false' )
if not viewable:
current = self.itemcget(item,'tags')
if isinstance(current, tuple):
new = current-('viewable',)
else:
print('here',points, (x1,y1,x2,y2))
new = ''
self.inview_items.discard(item)
self.itemconfigure(item,tags=new)
for item in self.find_overlapping(x1,y1,x2,y2):
#check if item inside of viewing_box not in inview_items
if item not in self.inview_items:
self.inview_items.add(item)
current = self.itemcget(item,'tags')
if isinstance(current, tuple):
new = current+('viewable',)
elif isinstance(current, str):
if str:
new = (current, 'viewable')
else:
new = 'viewable'
self.itemconfigure(item,tags=new)
print(self.inview_items)
def _create(self, *args):
if (current:=args[-1].get('tags', False)):
args[-1]['tags'] = current+('viewable',)
else:
args[-1]['tags'] = ('viewable',)
ident = super()._create(*args)
self._scan_view()
return ident
def _hscroll(self,event):
offset = int(event.delta/120)
if self._multi:
offset = int(offset*self._multi)
canvas.move('all', offset,0)
self._xshifted += offset
self._scan_view()
def _vscroll(self,event):
offset = int(event.delta/120)
if self._multi:
offset = int(offset*self._multi)
canvas.move('all', 0,offset)
self._yshifted += offset
self._scan_view()
root = tk.Tk()
canvas = InfiniteCanvas(root)
canvas.pack(fill=tk.BOTH, expand=True)
size, offset, start = 100, 10, 0
canvas.create_rectangle(start,start, size,size, fill='green')
canvas.create_rectangle(
start+offset,start+offset, size+offset,size+offset, fill='darkgreen')
root.mainloop()
PS: Before thinking this is over-complicated and using just find_overlapping isn't working, since it seems the item needs to be at least 51% in the view to get tracked with tkinters algorithm.
I still don't know what I have done wrong but it works with scan_dragto.
import tkinter as tk
class InfiniteCanvas(tk.Canvas):
def __init__(self, master, **kwargs):
super().__init__(master, **kwargs)
self.inview_items = set() #in view
self.niview_items = set() #not in view
self._xshifted = 0 #view moved in x direction
self._yshifted = 0 #view moved in y direction
self._multi = 0
self.configure(confine=False,highlightthickness=0,bd=0)
self.bind('<MouseWheel>', self._vscroll)
self.bind('<Shift-MouseWheel>', self._hscroll)
root.bind('<Control-KeyPress>',lambda e:setattr(self,'_multi', 10))
root.bind('<Control-KeyRelease>',lambda e:setattr(self,'_multi', 0))
return None
def viewing_box(self):
'returns x1,y1,x2,y2 of the currently visible area'
x1 = 0 - self._xshifted
y1 = 0 - self._yshifted
x2 = self.winfo_reqwidth()-self._xshifted
y2 = self.winfo_reqheight()-self._yshifted
return x1,y1,x2,y2
def _scan_view(self):
x1,y1,x2,y2 = self.viewing_box()
for item in self.find_withtag('viewable'):
#check if one felt over the edge
coords = self.coords(item)
#https://www.geeksforgeeks.org/python-split-tuple-into-groups-of-n/
points = tuple(
coords[x:x + 2] for x in range(0, len(coords), 2))
viewable = False
for point in points:
if x1 <= point[0] <= x2 and y1 <= point[1] <= y2:
#if any point is in viewing box
viewable = True
if not viewable:
current = self.itemcget(item,'tags')
if isinstance(current, tuple):
new = current-('viewable',)
else:
print('here',points, (x1,y1,x2,y2))
new = ''
self.inview_items.discard(item)
self.itemconfigure(item,tags=new)
for item in self.find_overlapping(x1,y1,x2,y2):
#check if item inside of viewing_box not in inview_items
if item not in self.inview_items:
self.inview_items.add(item)
current = self.itemcget(item,'tags')
if isinstance(current, tuple):
new = current+('viewable',)
elif isinstance(current, str):
if str:
new = (current, 'viewable')
else:
new = 'viewable'
self.itemconfigure(item,tags=new)
print(self.inview_items)
def _create(self, *args):
if (current:=args[-1].get('tags', False)):
args[-1]['tags'] = current+('viewable',)
else:
args[-1]['tags'] = ('viewable',)
ident = super()._create(*args)
self._scan_view()
return ident
def _hscroll(self,event):
offset = int(event.delta/120)
if self._multi:
offset = int(offset*self._multi)
cx,cy = self.winfo_rootx(), self.winfo_rooty()
self.scan_mark(cx, cy)
self.scan_dragto(cx+offset, cy, gain=1)
self._xshifted += offset
self._scan_view()
def _vscroll(self,event):
offset = int(event.delta/120)
if self._multi:
offset = int(offset*self._multi)
cx,cy = self.winfo_rootx(), self.winfo_rooty()
self.scan_mark(cx, cy)
self.scan_dragto(cx, cy+offset, gain=1)
self._yshifted += offset
self._scan_view()
root = tk.Tk()
canvas = InfiniteCanvas(root)
canvas.pack(fill=tk.BOTH, expand=True)
size, offset, start = 100, 10, 0
canvas.create_rectangle(start,start, size,size, fill='green')
canvas.create_rectangle(
start+offset,start+offset, size+offset,size+offset, fill='darkgreen')
root.mainloop()