DisplayProgressBar: honour min_value when computing fill width

Reported as #954.
DisplayProgressBar computes the filled extent from the raw value
rather than the value's offset from min_value:

    bar_filled_width = (value / (max_value - min_value) * width) - 1

When min_value is 0 (default) this happens to be correct, which is
why the bug has not surfaced. For any bar with a non-zero minimum
(e.g. a temperature bar with min=25, max=95) the fill is wrong:
value=25 renders at 36% instead of 0%, value=95 overshoots the bar.
DisplayRadialProgressBar already uses the offset-from-min formula a
couple of hundred lines down, so the two bar primitives are now
consistent.

Fixes #954

Signed-off-by: Sai Asish Y <say.apm35@gmail.com>

Author: SAY-5

library/lcd/lcd_comm.py

@@ -357,13 +357,17 @@ def DisplayProgressBar(self, x: int, y: int, width: int, height: int, min_value:
             # Crop bitmap to keep only the progress bar background
             bar_image = bar_image.crop(box=(x, y, x + width, y + height))
 
-        # Draw progress bar
+        # Draw progress bar. Fill has to be computed from the offset
+        # into [min_value, max_value], not the raw value; otherwise a
+        # bar with min_value > 0 (e.g. a 25..95 temperature bar) is
+        # filled by the wrong fraction. DisplayRadialProgressBar below
+        # already does this correctly. See issue #954.
         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)