Search code examples
pythontkintermouse-coordinates

Python can't find tkinter item at coordinates

I have this code:

for item in items:
    print ( "Item: ", item, mycanvas.coords (item) )

print ("Item at 26.0, 188.0 ", mycanvas.find_closest(26.0, 188.0))
print ("Item at 998.0, 594.0 ", mycanvas.find_closest(998.0, 594.0))

When I run it I get:

('Item: ', 1, [985.0, 565.0])
('Item: ', 8, [25.0, 25.0])
('Item: ', 15, [505.0, 25.0])
('Item: ', 28, [1362.0, 31.0])
('Item: ', 35, [1020.0, 119.0])
('Item: ', 42, [1050.0, 583.0])
('Item: ', 49, [25.0, 25.0])
('Item: ', 56, [26.0, 188.0])
('Item: ', 63, [998.0, 594.0])
('Item: ', 70, [1152.0, 38.0])
('Item at 26.0, 188.0 ', (57,))
('Item at 998.0, 594.0 ', (64,))

The last two lines should read items 56 and 63 found, respectively.

I have 10 images on the screen and am trying to find out which one is being clicked on. To make matters worse X, Y coordinates are being passed for the screen position and not the canvas position and I'll have to figure out how to convert:

def popup(event):
    x = mycanvas.canvasx(event.x_root)
    y = mycanvas.canvasy(event.y_root)
    print( "Adjusted x, y: ", x, y )
    FoundItem=mycanvas.find_closest(x, y)
    print( "Found Item @ x, y: ", FoundItem, event.x_root, event.y_root )
    FoundTuple=mycanvas.find_overlapping(x, y, x+1, y+1)
    print( "Found Tuple: ", FoundTuple )
    # use coordinates relative to the canvas
#    ItemNdx=items.index(FoundItem)
#    print( "ItemNdx: ", ItemNdx )
    menu.tk_popup(event.x_root, event.y_root)

In Python's Tkinter what's the easiest way to find out which image (item/ tag ID) a user has clicked on?

Monitor image with Window Images

To give an idea of what the canvas looks like:

wman2 edp-1-1.png

This is the portion for one of the three monitors eDP-1-1. Giving worst case scenario there are four windows open:

  • gedit with this source code in question open on bottom.
  • Firefox browser with this Q&A open above that.
  • Nautilus windows above that.
  • Gnome-terminal on the top.

Window stacking order isn't perfect yet because wmctrl is used to get all open windows on desktop without any sorting by stacking order yet.

So the user would click closest to the top left corner of the image they want to select. User could also click empty monitor area not covered by a window to select the monitor image. - Firefox browser with this website

Tag current is also one off

I put in this code:

tag_current=event.widget.find_withtag("current")
print ("tag_current: ", tag_current)

And the results were this:

('Item: ', 1, [985.0, 565.0])
('Item: ', 8, [25.0, 25.0])
('Item: ', 15, [505.0, 25.0])
('Item: ', 28, [1362.0, 31.0])
('Item: ', 35, [949.0, 167.0])
('Item: ', 42, [1050.0, 583.0])
('Item: ', 49, [83.0, 52.0])
('Item: ', 56, [26.0, 188.0])
('Item: ', 63, [998.0, 594.0])
('Item: ', 70, [25.0, 25.0])
('Item: ', 77, [1091.0, 644.0])
('Item at 26.0, 188.0 ', (70,))
('Item at 998.0, 594.0 ', (64,))
('tag_current: ', (41,))

tag_current should be 42 but is being reported as 41.

Much the same problem where 63 is reported as 64 and 56 is being reported as 70 (previously reported as 57 last time job was run).

12 hour update

12 hours later and I'm getting closer. It is necessary to convert from Window coordinates (entire desktop of three monitors) to canvas coordinates (one Python program on one of the monitors):

def popup(event):
    global FoundItem, MouseXY
    x = mycanvas.canvasx(event.x)
    y = mycanvas.canvasy(event.y)
    MouseXY=(x, y)
    print( "Adjusted x, y: ", x, y )
    FoundItem=mycanvas.find_closest(x, y)

Hopefully by tonight problem will be solved...

Solution

  • Here is the final solution to make it work:

    def popup(event):
    global FoundItem
#    print( "Root x, y: ", event.x_root, event.y_root )
#    print( "event x, y: ", event.x, event.y )
    FoundItem=mycanvas.find_closest(event.x, event.y)
    menu.tk_popup(event.x_root, event.y_root)

    You can remove the comments (# character) to see the x,y coordinates in your terminal.

    • The .tk_popup or .post command expects Screen Desktop coordinates: (event.x_root, event.y_root)
    • The .find_closest command expects Canvas coordinates: (event.x, event.y)