Add anchor parameter to DisplayText

The anchor parameter is required to easily (and correctly) placing text
on the drawn image.

See https://pillow.readthedocs.io/en/stable/handbook/text-anchors.html

Author: hchargois

library/lcd/lcd_comm.py

@@ -21,6 +21,7 @@
 import sys
 import threading
 import time
+import math
 from abc import ABC, abstractmethod
 from enum import IntEnum
 from typing import Tuple
@@ -206,7 +207,8 @@ def DisplayText(
             font_color: Tuple[int, int, int] = (0, 0, 0),
             background_color: Tuple[int, int, int] = (255, 255, 255),
             background_image: str = None,
-            align: str = 'left'
+            align: str = 'left',
+            anchor: str = None,
     ):
         # Convert text to bitmap using PIL and display it
         # Provide the background image path to display text with transparent background
@@ -238,19 +240,26 @@ def DisplayText(
         # Get text bounding box
         font = ImageFont.truetype("./res/fonts/" + font, font_size)
         d = ImageDraw.Draw(text_image)
-        left, top, text_width, text_height = d.textbbox((0, 0), text, font=font)
+        left, top, right, bottom = d.textbbox((x, y), text, font=font, align=align, anchor=anchor)
 
-        # Draw text with specified color & font, remove left/top margins
-        d.text((x - left, y - top), text, font=font, fill=font_color, align=align)
+        # textbbox may return float values, which is not good for the bitmap operations below.
+        # Let's extend the bounding box to the next whole pixel in all directions
+        left, top = math.floor(left), math.floor(top)
+        right, bottom = math.ceil(right), math.ceil(bottom)
 
-        # Crop text bitmap to keep only the text (also crop if text overflows display)
-        text_image = text_image.crop(box=(
-            x, y,
-            min(x + text_width - left, self.get_width()),
-            min(y + text_height - top, self.get_height())
-        ))
+        # Draw text onto the background image with specified color & font
+        d.text((x, y), text, font=font, fill=font_color, align=align, anchor=anchor)
 
-        self.DisplayPILImage(text_image, x, y)
+        # Restrict the dimensions if they overflow the display size
+        left = max(left, 0)
+        top = max(top, 0)
+        right = min(right, self.get_width())
+        bottom = min(bottom, self.get_height())
+
+        # Crop text bitmap to keep only the text
+        text_image = text_image.crop(box=(left, top, right, bottom))
+
+        self.DisplayPILImage(text_image, left, top)
 
     def DisplayProgressBar(self, x: int, y: int, width: int, height: int, min_value: int = 0, max_value: int = 100,
                            value: int = 50,