PySimpleGUI/DemoPrograms/Demo_Graph_Drag_Rectangle.py

59 lines
1.9 KiB
Python

import PySimpleGUI as sg
"""
Demo - Drag a rectangle to draw it
This demo shows how to use a Graph Element to (optionally) display an image and then use the
mouse to "drag a rectangle". This is sometimes called a rubber band and is an operation you
see in things like editors
"""
# image_file = r'Color-names.png'
# image_file = None # image is optional
image_file = r'C:\Python\PycharmProjects\GooeyGUI\logo200.png' # image is optional
layout = [[sg.Graph(
canvas_size=(400, 400),
graph_bottom_left=(0, 0),
graph_top_right=(400, 400),
key="-GRAPH-",
change_submits=True, # mouse click events
background_color='lightblue',
drag_submits=True), ],
[sg.Text(key='info', size=(60, 1))]]
window = sg.Window("draw rect on image", layout, finalize=True)
# get the graph element for ease of use later
graph = window["-GRAPH-"] # type: sg.Graph
graph.draw_image(image_file, location=(0,400)) if image_file else None
dragging = False
start_point = end_point = prior_rect = None
while True:
event, values = window.read()
if event is None:
break # exit
if event == "-GRAPH-": # if there's a "Graph" event, then it's a mouse
x, y = values["-GRAPH-"]
if not dragging:
start_point = (x, y)
dragging = True
else:
end_point = (x, y)
if prior_rect:
graph.delete_figure(prior_rect)
if None not in (start_point, end_point):
prior_rect = graph.draw_rectangle(start_point, end_point, line_color='red')
elif event.endswith('+UP'): # The drawing has ended because mouse up
info = window["info"]
info.update(value=f"grabbed rectangle from {start_point} to {end_point}")
start_point, end_point = None, None # enable grabbing a new rect
dragging = False
else:
print("unhandled event", event, values)