From f651b49d05a0046cc47acfacecb54639caebff09 Mon Sep 17 00:00:00 2001
From: MikeTheWatchGuy <mike_barnett@hotmail.com>
Date: Mon, 3 Sep 2018 16:52:22 -0400
Subject: [PATCH] Initial checkin into Dev branch

---
 Demo_Img_Viewer.py | 115 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 115 insertions(+)
 create mode 100644 Demo_Img_Viewer.py

diff --git a/Demo_Img_Viewer.py b/Demo_Img_Viewer.py
new file mode 100644
index 00000000..00f23a6d
--- /dev/null
+++ b/Demo_Img_Viewer.py
@@ -0,0 +1,115 @@
+import PySimpleGUI as sg
+import os
+from PIL import Image, ImageTk
+import io
+"""
+Simple Image Browser based on PySimpleGUI
+--------------------------------------------
+There are some improvements compared to the PNG browser of the repository:
+1. Paging is cyclic, i.e. automatically wraps around if file index is outside
+2. Supports all file types that are valid PIL images
+3. Limits the maximum form size to the physical screen
+4. When selecting an image from the listbox, subsequent paging uses its index
+5. Paging performance improved significantly because of using PIL
+
+Dependecies
+------------
+Python v3
+PIL
+"""
+# Get the folder containing the images from the user
+rc, folder = sg.GetPathBox('Image Browser', 'Image folder to open', default_path='')
+if not rc or not folder:
+    sg.PopupCancel('Cancelling')
+    raise SystemExit()
+
+# PIL supported image types
+img_types = (".png", ".jpg", "jpeg", ".tiff", ".bmp")
+
+# get list of files in folder
+flist0 = os.listdir(folder)
+
+# create sub list of image files (no sub folders, no wrong file types)
+fnames = [f for f in flist0 if os.path.isfile(os.path.join(folder,f)) and f.lower().endswith(img_types)]
+
+num_files = len(fnames)                # number of iamges found
+if num_files == 0:
+    sg.Popup('No files in folder')
+    raise SystemExit()
+
+del flist0                             # no longer needed
+
+#------------------------------------------------------------------------------
+# use PIL to read data of one image
+#------------------------------------------------------------------------------
+def get_img_data(f, maxsize = (1200, 850), first = False):
+    """Generate image data using PIL
+    """
+    img = Image.open(f)
+    img.thumbnail(maxsize)
+    if first:                     # tkinter is inactive the first time
+        bio = io.BytesIO()
+        img.save(bio, format = "PNG")
+        del img
+        return bio.getvalue()
+    return ImageTk.PhotoImage(img)
+#------------------------------------------------------------------------------
+
+
+# create the form that also returns keyboard events
+form = sg.FlexForm('Image Browser', return_keyboard_events=True,
+                   location=(0, 0), use_default_focus=False)
+
+# make these 2 elements outside the layout as we want to "update" them later
+# initialize to the first file in the list
+filename = os.path.join(folder, fnames[0])  # name of first file in list
+image_elem = sg.Image(data = get_img_data(filename, first = True))
+filename_display_elem = sg.Text(filename, size=(80, 3))
+file_num_display_elem = sg.Text('File 1 of {}'.format(num_files), size=(15,1))
+
+# define layout, show and read the form
+col = [[filename_display_elem],
+          [image_elem]]
+
+col_files = [[sg.Listbox(values = fnames, select_submits=True, size=(60,30), key='listbox')],
+             [sg.ReadFormButton('Next', size=(8,2)), sg.ReadFormButton('Prev',
+                             size=(8,2)), file_num_display_elem]]
+
+layout = [[sg.Column(col_files), sg.Column(col)]]
+
+form.Layout(layout)          # Shows form on screen
+
+# loop reading the user input and displaying image, filename
+i=0
+while True:
+    # read the form
+    button, values = form.Read()
+
+    # perform button and keyboard operations
+    if button is None:
+        break
+    elif button in ('Next', 'MouseWheel:Down', 'Down:40', 'Next:34'):
+        i += 1
+        if i >= num_files:
+            i -= num_files
+        filename = os.path.join(folder, fnames[i])
+    elif button in ('Prev', 'MouseWheel:Up', 'Up:38', 'Prior:33'):
+        i -= 1
+        if i < 0:
+            i = num_files + i
+        filename = os.path.join(folder, fnames[i])
+    elif button in ('Read', ''):            # something from the listbox
+        f = values["listbox"][0]            # selected filename
+        filename = os.path.join(folder, f)  # read this file
+        i = fnames.index(f)                 # update running index
+    else:
+        filename = os.path.join(folder, fnames[i])
+
+    # update window with new image
+    image_elem.Update(data=get_img_data(filename))
+    # update window with filename
+    filename_display_elem.Update(filename)
+    # update page display
+    file_num_display_elem.Update('File {} of {}'.format(i+1, num_files))
+
+