New demo program using new function save_element_as_file . Added save to the Graph drawing demo

DemoPrograms/Demo_Save_Window_As_Image.py

@@ -0,0 +1,48 @@
+import PySimpleGUI as sg
+from PIL import ImageGrab
+
+"""
+    Demo - Saving the contents of a window as an image file
+    
+    This demo will teach you how to save any portion of your window to an image file.
+    You can save in JPG, GIF, or PNG format.
+    
+    In this example the entire window's layout is placed into a single Column Element.  This allows
+    us to save an image of the Column which saves the entire window layout
+    
+    Portions of windows can be saved, such as a Graph Element, by specifying the Graph Element instead of the Column
+"""
+
+def save_element_as_file(element, filename):
+    """
+    Saves any element as an image file.  Element needs to have an underlyiong Widget available (almost if not all of them do)
+    :param element: The element to save
+    :param filename: The filename to save to. The extension of the filename determines the format (jpg, png, gif, ?)
+    """
+    widget = element.Widget
+    box = (widget.winfo_rootx(), widget.winfo_rooty(), widget.winfo_rootx() + widget.winfo_width(), widget.winfo_rooty() + widget.winfo_height())
+    grab = ImageGrab.grab(bbox=box)
+    grab.save(filename)
+
+
+def main():
+
+    col = [[sg.Text('This is the first line')],
+           [sg.In()],
+           [sg.Button('Save'), sg.Button('Exit')]]
+
+    layout = [[sg.Column(col, key='-COLUMN-')]]     # put entire layout into a column so it can be saved
+
+    window = sg.Window("Drawing and Moving Stuff Around", layout)
+
+    while True:
+        event, values = window.read()
+        if event in (None, 'Exit'):
+            break  # exit
+        elif event == 'Save':
+            filename = sg.popup_get_file('Choose file (PNG, JPG, GIF) to save to', save_as=True)
+            save_element_as_file(window['-COLUMN-'], filename)
+
+    window.close()
+
+main()