Moved all demo programs into subfolder

DemoPrograms/Demo_PNG_Thumbnail_Viewer.py

@@ -0,0 +1,130 @@
+#!/usr/bin/env python
+import sys
+if sys.version_info[0] >= 3:
+    import PySimpleGUI as sg
+else:
+    import PySimpleGUI27 as sg
+import os
+from sys import exit as exit
+from  PIL import Image
+import io
+import numpy as np
+
+thumbnails = {}
+
+ROWS = 8
+COLUMNS = 8
+sg.SetOptions(border_width=0)
+# Get the folder containing the images from the user
+# folder = 'A:/TEMP/pdfs'
+folder = sg.PopupGetFolder('Image folder to open')
+if folder is None:
+    sg.PopupCancel('Cancelling')
+    exit(0)
+def image_file_to_bytes(filename, size):
+    try:
+        image = Image.open(filename)
+        image.thumbnail(size, Image.ANTIALIAS)
+        bio = io.BytesIO()  # a binary memory resident stream
+        image.save(bio, format='PNG')  # save image as png to it
+        imgbytes = bio.getvalue()
+    except:
+        imgbytes = None
+    return imgbytes
+
+def set_image_to_blank(key):
+    img = Image.new('RGB', (100, 100), (255, 255, 255))
+    img.thumbnail((1, 1), Image.ANTIALIAS)
+    bio = io.BytesIO()
+    img.save(bio, format='PNG')
+    imgbytes = bio.getvalue()
+    window.FindElement(key).Update(image_data=imgbytes)
+
+
+
+# get list of PNG files in folder
+png_files = [os.path.join(folder, f) for f in os.listdir(folder) if '.png' in f]
+filenames_only = [f for f in os.listdir(folder) if '.png' in f]
+
+if len(png_files) == 0:
+    sg.Popup('No PNG images in folder')
+    exit(0)
+
+# define menu layout
+menu = [['&File', ['&Open Folder', 'E&xit']], ['&Help', ['&About',]]]
+
+buttons = []
+for display_index in range(ROWS):
+    row = []
+    for j in range(COLUMNS):
+        row.append(sg.Button('',border_width=0,button_color=sg.COLOR_SYSTEM_DEFAULT, key=(display_index, j)))
+    buttons.append(row)
+
+col_buttons = [[]]
+
+# define layout, show and read the window
+col = [[sg.Text(png_files[0], size=(80, 3), key='filename')],
+          [sg.Image(data=image_file_to_bytes(png_files[0], (500,500)), key='image')],]
+
+layout = [[sg.Menu(menu)], [sg.Column(buttons), sg.Column([[sg.Slider((len(png_files),0),default_value=0,size=(38,20),orientation='v', key='_slider_', change_submits=True)]]), sg.Column(col)]]
+window = sg.Window('Image Browser',
+                   return_keyboard_events=True,
+                   use_default_focus=False ).Layout(layout).Finalize()
+
+# -------========= Event Loop =========--------
+display_index=0
+while True:
+    for x in range(ROWS):               # update thumbnails
+        for y in range(COLUMNS):
+            cur_index = display_index + (x * 4) + y
+            if cur_index < len(png_files):
+                filename = png_files[cur_index]
+                if filename not in thumbnails:
+                    imgbytes = image_file_to_bytes(filename, (100,100))
+                    thumbnails[filename] = imgbytes
+                else:
+                    imgbytes = thumbnails[filename]
+                button_elem = window.FindElement(key=(x,y))
+                button_elem.Update(image_data=imgbytes)
+            else:
+                set_image_to_blank((x,y))
+
+    event, values = window.Read()
+    display_index = values['_slider_']
+    # --------------------- Button & Keyboard ---------------------
+    if event in (None, 'Exit'):
+        break
+    elif event in ('MouseWheel:Down', 'Down:40',) and display_index < len(png_files)-1:
+        display_index += 4
+    elif event in ('MouseWheel:Up', 'Up:38',) and display_index > 0:
+        display_index -= 4
+    elif event in ('Prior:33', 'Prev'):
+        display_index -= 16
+    elif event in ('Next:34', 'Next'):
+        display_index += 16
+
+    window.FindElement('_slider_').Update(display_index)
+    # ----------------- Menu choices -----------------
+    if event == 'Open Folder':
+        newfolder = sg.PopupGetFolder('New folder', no_window=True)
+        if newfolder is None:
+            continue
+        folder = newfolder
+        png_files = [os.path.join(folder, f) for f in os.listdir(folder) if '.png' in f]
+        filenames_only = [f for f in os.listdir(folder) if '.png' in f]
+        display_index = 0
+        thumbnail = {}
+        for j in range(ROWS):
+            for i in range(COLUMNS):
+                set_image_to_blank((i,j))
+    elif event == 'About':
+        sg.Popup('Demo PNG Viewer Program', 'Please give PySimpleGUI a try!')
+    elif type(event) is tuple:
+        x, y = event
+        image_index = display_index + (x * 4) + y
+        if image_index < len(png_files):
+            filename = png_files[image_index]
+            imgbytes = image_file_to_bytes(filename, (500, 500))
+            window.FindElement('image').Update(data=imgbytes)
+            window.FindElement('filename').Update(filename)
+