New Demo that shows all of the look and feel choices. Runs on all ports (except Wx)

DemoPrograms/Demo_LookAndFeel_Previewer.py

@@ -0,0 +1,23 @@
+import PySimpleGUI as sg; web=False
+# import PySimpleGUIWeb as sg; web=True
+# import PySimpleGUIQT as sg; web=False
+
+WINDOW_BACKGROUND = 'lightblue'
+
+def sample_layout():
+    return [[sg.Text('Text element'), sg.InputText('Input data here', size=(15,1))],
+                [sg.Button('Ok'), sg.Button('Cancel'), sg.Slider((1,10), orientation='h', size=(10,15)) ]]
+
+layout =   [[sg.Text('Here is a complete list of themes', font='Default 18', background_color=WINDOW_BACKGROUND)]]
+
+row = []
+for count, theme in enumerate(sg.ListOfLookAndFeelValues()):
+    sg.change_look_and_feel(theme)
+    if not count % 3:
+        layout += [row]
+        row = []
+    row += [sg.Frame(theme, sample_layout()  if not web else [[sg.T(theme)]]+sample_layout())]
+if row:
+    layout += [row]
+
+sg.Window('Preview of all Look and Feel choices', layout, background_color=WINDOW_BACKGROUND).read()