Fix DisplayProgressBar min_value offset in fill calculation

DisplayProgressBar calculated bar_filled_width/height from the raw
value rather than the value's offset from min_value. When min_value
was 0 (the default), this had no effect — which is why the bug went
unnoticed — but any bar with a non-zero minimum rendered the fill
incorrectly.

DisplayRadialProgressBar already uses the correct form
(value - min_value) / (max_value - min_value).

Fixes #954

Author: matthewgjohnson

library/lcd/lcd_comm.py

@@ -359,11 +359,11 @@ def DisplayProgressBar(self, x: int, y: int, width: int, height: int, min_value:
 
         # Draw progress bar
         if width > height:
-            bar_filled_width = (value / (max_value - min_value) * width) - 1
+            bar_filled_width = ((value - min_value) / (max_value - min_value) * width) - 1
             if bar_filled_width < 0:
                 bar_filled_width = 0
         else:
-            bar_filled_height = (value / (max_value - min_value) * height) - 1
+            bar_filled_height = ((value - min_value) / (max_value - min_value) * height) - 1
             if bar_filled_height < 0:
                 bar_filled_height = 0
         draw = ImageDraw.Draw(bar_image)