Major update of all demo programs to use new PEP8 bindings, etc

DemoPrograms old/Demo_OpenCV.py

@@ -0,0 +1,72 @@
+#!/usr/bin/env python
+import sys
+if sys.version_info[0] >= 3:
+    import PySimpleGUI as sg
+else:
+    import PySimpleGUI27 as sg
+import cv2 as cv
+from PIL import Image
+import io
+from sys import exit as exit
+
+"""
+Demo program to open and play a file using OpenCV
+It's main purpose is to show you:
+1. How to get a frame at a time from a video file using OpenCV
+2. How to display an image in a PySimpleGUI Window
+
+For added fun, you can reposition the video using the slider.
+"""
+
+def main():
+    # ---===--- Get the filename --- #
+    filename = sg.PopupGetFile('Filename to play')
+    if filename is None:
+        exit(69)
+    vidFile = cv.VideoCapture(filename)
+    # ---===--- Get some Stats --- #
+    num_frames = vidFile.get(cv.CAP_PROP_FRAME_COUNT)
+    fps = vidFile.get(cv.CAP_PROP_FPS)
+
+    sg.ChangeLookAndFeel('Black')
+
+    # ---===--- define the window layout --- #
+    layout = [[sg.Text('OpenCV Demo', size=(15, 1), font='Helvetica 20')],
+              [sg.Image(filename='', key='_image_')],
+              [sg.Slider(range=(0, num_frames), size=(60, 10), orientation='h', key='_slider_')],
+              [sg.Button('Exit', size=(7, 1), pad=((600, 0), 3), font='Helvetica 14')]]
+
+    # create the window and show it without the plot
+    window = sg.Window('Demo Application - OpenCV Integration', no_titlebar=False, location=(0,0)).Layout(layout)
+
+    image_elem = window.Element('_image_')    # locate the elements we'll be updating. Does the search only 1 time
+    slider_elem = window.Element('_slider_')
+
+    # ---===--- LOOP through video file by frame --- #
+    cur_frame = 0
+    while vidFile.isOpened():
+        event, values = window.Read(timeout=0)
+        if event in ('Exit', None):
+            exit(69)
+        ret, frame = vidFile.read()
+        if not ret:  # if out of data stop looping
+            break
+        if int(values['_slider_']) != cur_frame-1:        # if someone moved the slider manually, the jump to that frame
+            cur_frame = int(values['_slider_'])
+            vidFile.set(cv.CAP_PROP_POS_FRAMES, cur_frame)
+        slider_elem.Update(cur_frame)
+        cur_frame += 1
+
+        imgbytes = cv.imencode('.png', frame)[1].tobytes()  # ditto
+        image_elem.Update(data=imgbytes)
+
+"""
+        # This was another way updates were being done, but seems slower than the above
+        img = Image.fromarray(frame)    # create PIL image from frame
+        bio = io.BytesIO()              # a binary memory resident stream
+        img.save(bio, format= 'PNG')    # save image as png to it
+        imgbytes = bio.getvalue()       # this can be used by OpenCV hopefully
+        image_elem.Update(data=imgbytes)
+"""
+
+main()