New Demo to display images using Graph Element

DemoPrograms/Demo_Graph_Elem_Image_Album.py

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+#!/usr/bin/env python
+import PySimpleGUI as sg
+from PIL import Image
+import PIL
+import io
+import base64
+import os
+
+"""
+    Demo Image Album.... displays images on Graph Element and transitions
+    by sliding them across.  Click on right side of image to navigate down through filenames, left side for up.
+    
+    Contains a couple of handy PIL-based image functions that resize an image while maintaining correct proportion.
+    One you pass a filename, the other a BASE64 string.
+    
+    Copyright 2020 PySimpleGUI.org
+"""
+
+G_SIZE = (400,400)
+
+def get_img_filename(f, resize=None):
+    """Generate image data using PIL
+    """
+    img = PIL.Image.open(f)
+    cur_width, cur_height = img.size
+    if resize:
+        new_width, new_height = resize
+        if cur_width > cur_height:
+            new_height = int(new_height * cur_height/cur_width)
+        else:
+            new_width = int(new_width * cur_width/cur_height)
+        img = img.resize((new_width, new_height), PIL.Image.ANTIALIAS)
+    bio = io.BytesIO()
+    img.save(bio, format="PNG")
+    del img
+    return bio.getvalue()
+
+
+def get_img_data(data, resize=None):
+    """Generate PIL.Image data using PIL
+    """
+    img = PIL.Image.open(io.BytesIO(base64.b64decode(data)))
+    cur_width, cur_height = img.size
+    if resize:
+        new_width, new_height = resize
+        if cur_width > cur_height:
+            new_height = int(new_height * cur_height/cur_width)
+        else:
+            new_width = int(new_width * cur_width/cur_height)
+        img = img.resize((new_width, new_height), PIL.Image.ANTIALIAS)
+    bio = io.BytesIO()
+    img.save(bio, format="PNG")
+    del img
+    return bio.getvalue()
+
+folder = sg.popup_get_folder('Where are your images?')
+if not folder:
+    exit(0)
+
+file_list = os.listdir(folder)
+fnames = [f for f in file_list if os.path.isfile(
+    os.path.join(folder, f)) and f.lower().endswith((".png", ".jpg", "jpeg", ".tiff", ".bmp"))]
+num_files = len(fnames)
+
+graph = sg.Graph(canvas_size=G_SIZE, graph_bottom_left=(0, 0), graph_top_right=G_SIZE, enable_events=True, key='-GRAPH-')
+layout = [[graph]]
+
+window = sg.Window('Scrolling Image Viewer', layout, margins=(0,0), element_padding=(0,0), use_default_focus=False, finalize=True)
+
+offset, move_amount, direction  = 0, 5, 'left'
+while True:
+    file_to_display = os.path.join(folder, fnames[offset])
+    img_data = get_img_filename(file_to_display, resize=G_SIZE)
+    id = graph.draw_image(data=img_data, location=(0, G_SIZE[1]))
+
+    event, values = window.read()
+    if event == sg.WIN_CLOSED:
+        break
+
+    if event in ('<', '>'):
+        direction = 'left' if event == '<' else 'right'
+    elif event == '-GRAPH-':
+        direction = 'left' if values['-GRAPH-'][0] < (G_SIZE[0] // 2) else 'right'
+
+    for i in range(G_SIZE[0]//move_amount):
+        graph.move_figure(id, -move_amount if direction == 'left' else move_amount, 0)
+        window.read(timeout=0)
+    graph.delete_figure(id)
+
+    if direction == 'left':
+        offset = (offset + (num_files - 1)) % num_files     # Decrement - roll over to MAX from 0
+    else:
+        offset = (offset + 1) % num_files                   # Increment to MAX then roll over to 0
+
+window.close()