enabling drag_submits enables mouse_drags, but disables mouse_up events

[finlay-mcwalter]

Type of Issues (Enhancement, Error, Bug, Question)

Bug

Operating System

Ubuntu linux 19.04 (kernel 5.0.0-21) x86_64

Python version

3.7.3

PySimpleGUI Port and Version

Tk
4.0.0

Code or partial code causing the problem

enabling drag_submits on a graph stops it from receiving mouse button up events - set drag_submits False in the attached code and see the mouse up events, set it True and they're not reported. Sometimes a TIMEOUT is reported instead, but in practical examples that's not consistent. I'm using this to implement a rubber-rect drawing (with PIL in the background for double-buffering) but without reliable mouse_up, one can't know when one is done rubberbanding.

#!/usr/bin/python3

import PySimpleGUI as sg
    
layout = [
    [
        sg.Graph(
            canvas_size=(400, 400),
            graph_bottom_left=(0, 400),
            graph_top_right=(400, 0),
            key="graph",
            change_submits=True,

            # enabling drag_submits enables mouse_drags, but disables mouse_up events
            drag_submits=True 
        )
    ]
]

window = sg.Window("mouse events", layout)
window.Finalize()

graph = window.Element("graph")


while True:
    event, values = window.Read()
    if event is None:
        break # exit

    if event == "graph":
        x,y = values["graph"]
        if x is None:
            print ("UP")
        else:
            print (f"DOWN {values['graph']}")
    
    else:
        print(event, values)

[MikeTheWatchGuy]

You're correct, that it's the timeout that you should be keying on for the end of the sequence.

[MikeTheWatchGuy]

I also think the graph return value of None was supposed to be what was meant to be the thing you actually look for. The Timeout key was the best way at the time of getting the info back to the application so that you would know it's an Up event.

[MikeTheWatchGuy]

I'll look through the design again. I recall there being a bit of a problem in when the mouse up event came in, etc. I didn't have access to mouse position for example, which is why None is returned. The idea being the user code would recall the "last known point", but I'll see if I can capture some of that myself.

[finlay-mcwalter]

The TIMEOUT way would be fine, but it seems that in my "real" example (which does some fairly beefy redrawing when handing a mouse event) only some down-drag-up sequences yield a TIMEOUT (the rest don't, leaving the last mousedown from the drag as the last event the script has seen).

Here, fyi, is that code.

DRAW.ZIP

[MikeTheWatchGuy]

Oh...... intermittent, that's not good.

I thought I had it right, but I guess I did for my examples and still have more to go.

[MikeTheWatchGuy]

Your zipped file crashes on me:

C:\Python\Anaconda3\python.exe E:/DownloadsE/draw_on_image.py
Traceback (most recent call last):
  File "E:/DownloadsE/draw_on_image.py", line 91, in <module>
    draw_frame(graph, start=start_point, end=end_point)
  File "E:/DownloadsE/draw_on_image.py", line 32, in draw_frame
    width=2)
TypeError: rectangle() got an unexpected keyword argument 'width'

Process finished with exit code 1

[MikeTheWatchGuy]

I just removed the parm and it still shows up so must not have been important.

Have a bit of patience with me on this one. Yours is the first application, ever, that's done this kind of drawing on a Graph. I thought I tested things out pretty well, but you just don't know until you hit a real-world example.

[MikeTheWatchGuy]

By the way, you need to delete those images as your program chews through memory at a pretty good clip. Looks like a few megabytes on every draw.

Also, why not use the built-in draw rectangle that the Graph Element provides?

[finlay-mcwalter]

On Ubuntu, PIL is really Pillow (as the original PIL is effectively defunct) and that parameter may have been added by them.

Really, please don't stress at all about this. You've already been astonishingly helpful. I'm really only doing it to answer that Stack Overflow question linked in the program, and I've clearly gotten carried away :)

[PySimpleGUI]

OK, I'm working on this problem today.

The issue I recall grappling with was HOW, specifically, to indicate these various state transitions along with the data.

Click/drag events are easy. The graph's key is the event, the value for that key is (x,y) position.

A MOUSE-UP event, with a drag, is a bit trickier.

I can have it return (None, None) as the value to indicate that the mouse button was released.

What that does not give you is the location it was released.

I'm leaning on returning the (x,y) location,which you really do need, but return a "modified event".

How about returning the Graph Element's key with "+MOUSE_UP" added?

This way you can do an if event.startswith(graph_key): to generally detect graph stuff.

I'm going in this direction for the time being.... please provide input on your ideas for how the information can be returned.

[PySimpleGUI]

Done!

Please get a new copy of PySimpleGUI.py from the GitHub,

Here is another version of your program that utilizes the new mechanism.

I like this a LOT better! And, I cannot WAIT to see what you can do with it!!!!!

Sorry it took me a week and a half to get to and provide some kind of fix. Doing the best I can. Hoping you didn't give up while waiting.

#!/usr/bin/python3

import PySimpleGUI as sg

layout = [
    [
        sg.Graph(
            canvas_size=(400, 400),
            graph_bottom_left=(0, 400),
            graph_top_right=(400, 0),
            key="graph",
            change_submits=True,

            # enabling drag_submits enables mouse_drags, but disables mouse_up events
            drag_submits=True
        )
    ]
]

window = sg.Window("mouse events", layout)
window.Finalize()

graph = window.Element("graph")

while True:
    event, values = window.Read()
    if event is None:
        break  # exit
    # print(event, values)

    if event.startswith("graph"):
        x, y = values["graph"]
        if event.endswith('+UP'):
            print(f"UP {values['graph']}")
        else:
            print(f"DOWN {values['graph']}")

    else:
        print(event, values)