Adding explanations to the Gauge2

slightlynybbled · slightlynybbled · commit a893f2952902 · 2018-06-11T07:43:37.000-04:00
diff --git a/examples/gauge2.py b/examples/gauge2.py
@@ -1,43 +1,59 @@
 import tkinter as tk
 import tk_tools
 
-
 root = tk.Tk()
 
 max_speed = 20000
 
+# Typical one-sided gauge that you might be expecting for a
+# speedometer or tachometer.  Starts at zero and goes to
+# max_value when full-scale.
 speed_gauge = tk_tools.Gauge2(root,
-                             max_value=max_speed,
-                             label='speed', unit=' m/h',bg='grey')
+                              max_value=max_speed,
+                              label='speed',
+                              unit=' m/h',
+                              bg='grey')
 speed_gauge.grid(row=0, column=0, sticky='news')
 
-
 tach_gauge = tk_tools.Gauge2(root,
-                            max_value=8000,
-                            label='tach', unit=' RPM',
-                            divisions=10)
+                             max_value=8000,
+                             label='tach',
+                             unit=' RPM',
+                             divisions=10)
 tach_gauge.grid(row=1, column=0, sticky='news')
 
 strange_gauge = tk_tools.Gauge2(root,
-                               max_value=30000,
-                               label='strange', unit=' blah',
-                               divisions=10, red=90, yellow=60)
+                                max_value=30000,
+                                label='strange', unit=' blah',
+                                divisions=10, red=90, yellow=60)
 strange_gauge.grid(row=2, column=0, sticky='news')
 
-batV_gauge = tk_tools.Gauge2(root,       height=120, width=250,
-                                max_value=16, min_value=8,
-                                label='Bat voltage', unit='V',
-                                divisions=8, yellow=60, red=75,
-                                red_low=30, yellow_low=40)
+# The battery voltage gauge has a lower voltage limit and an
+# upper voltage limit.  These are automatically created when
+# one imposes values on red_low and yellow_low along with
+# using the min_value.
+batV_gauge = tk_tools.Gauge2(root, height=120, width=250,
+                             max_value=16, min_value=8,
+                             label='Bat voltage',
+                             unit='V',
+                             divisions=8,
+                             yellow=60,
+                             red=75,
+                             red_low=30,
+                             yellow_low=40)
 batV_gauge.grid(row=0, column=1, sticky='news')
 
-batI_gauge = tk_tools.Gauge2(root,       height=120, width=250,
-                                max_value=6, min_value=-8,
-                                label='Bat current', unit='A',
-                                divisions=14, yellow=80, red=90,
-                                red_low=20, yellow_low=30,bg='lavender')
+# Similar to the previous gauge with bi-directional, but shows an
+# imbalanced configuration along with support for negative numbers.
+batI_gauge = tk_tools.Gauge2(root, height=120, width=250,
+                             max_value=6,
+                             min_value=-8,
+                             label='Bat current', unit='A',
+                             divisions=14, yellow=80, red=90,
+                             red_low=20, yellow_low=30, bg='lavender')
 batI_gauge.grid(row=1, column=1, sticky='news')
 
+# initialization of some variables.
 count = 0
 up = True
 
@@ -57,15 +73,17 @@ def update_gauge():
         if count <= 0.0:
             up = True
 
+    # update the gauges according to their value
     speed_gauge.set_value(count)
     tach_gauge.set_value(count)
     strange_gauge.set_value(count)
-    batV_gauge.set_value(count/1000)
-    batI_gauge.set_value((count-10000)/1000)
+    batV_gauge.set_value(count / 1000)
+    batI_gauge.set_value((count - 10000) / 1000)
 
     root.after(50, update_gauge)
 
 
-root.after(100, update_gauge)
+if __name__ == '__main__':
+    root.after(100, update_gauge)
 
-root.mainloop()
+    root.mainloop()
