From b16782c39d168f0740447a3e12e0c52c0d92867d Mon Sep 17 00:00:00 2001
From: MikeTheWatchGuy <mike_barnett@hotmail.com>
Date: Mon, 8 Jul 2019 18:35:47 -0400
Subject: [PATCH] Made slider active. Moving it causes video playbcack to begin
 at new location indicated by slider.  Cleaned up code a little.

---
 DemoPrograms/Demo_OpenCV.py | 45 ++++++++++++++++++++-----------------
 1 file changed, 25 insertions(+), 20 deletions(-)

diff --git a/DemoPrograms/Demo_OpenCV.py b/DemoPrograms/Demo_OpenCV.py
index 473f1ad5..141c8648 100644
--- a/DemoPrograms/Demo_OpenCV.py
+++ b/DemoPrograms/Demo_OpenCV.py
@@ -11,13 +11,15 @@ from sys import exit as exit
 
 """
 Demo program to open and play a file using OpenCV
-Unsure how to get the frames coming from OpenCV into the right format, so saving each frame to
-a temp file.  Clearly... clearly... this is not the optimal solution and one is being searched for now.
+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
 
-Until then enjoy it working somewhat slowly.
+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)
@@ -26,19 +28,22 @@ def main():
     num_frames = vidFile.get(cv.CAP_PROP_FRAME_COUNT)
     fps = vidFile.get(cv.CAP_PROP_FPS)
 
-    sg.ChangeLookAndFeel('Dark')
+    sg.ChangeLookAndFeel('Black')
 
-    # define the window layout
-    layout = [[sg.Text('OpenCV Demo', size=(15, 1),pad=((510,0),3), justification='center', font='Helvetica 20')],
-              [sg.Image(filename='', key='image')],
-              [sg.Slider(range=(0, num_frames), size=(115, 10), orientation='h', key='slider')],
-              [sg.Button('Exit', size=(10, 2), pad=((600, 0), 3), font='Helvetica 14')]]
+    # ---===--- 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 --- #
-    i = 0
+    cur_frame = 0
     while vidFile.isOpened():
         event, values = window.Read(timeout=0)
         if event in ('Exit', None):
@@ -46,16 +51,16 @@ def main():
         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
 
-        window.FindElement('slider').Update(i)
-        i += 1
-
-        # let img be the PIL image
-        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
-        window.FindElement('image').Update(data=imgbytes)
-
+        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()
\ No newline at end of file