v.0.9.0 DigitalClock: optimzed update the display

app/utils/digital_clock.py

@@ -1,26 +1,58 @@
 from app.display.neopixel_64x64 import NeoPixel_64x64
-from app.utils import get_datetime_string
+from app.utils import get_datetime_string, text_width, find_first_mismatch
 from app.utils import colors
 
 
 class DigitalClock:
-    CLOCK_WIDTH = 38
+    stored_time_str: str = "99:99:99"
+    text_color: tuple[int[3]] = colors.NEON_YELLOW
+    clear_color: tuple[int[3]] = colors.BLACK
 
     def __init__(self, display: NeoPixel_64x64, xpos: int, ypos: int):
         self.display = display
         self.xpos = xpos
         self.ypos = ypos
 
+    def _toggle_clear_color(self) -> tuple[int]:
+        self.clear_color = (
+            colors.BLACK if self.clear_color != colors.BLACK else colors.MAGENTA
+        )
+        return self.clear_color
+
+    def _text_width(self, text: str) -> int:
+        return text_width(text, self.display.selected_font)
+
     async def tick(self):
-        time_str: str = get_datetime_string("time")
+        time_str: str = get_datetime_string("time")[:8]
+
+        # ab welcher Position malen wir den String neu
+        mismatch_pos: int = find_first_mismatch(self.stored_time_str, time_str)
+
+        untouched_part: str = time_str[:mismatch_pos]
+        fresh_part: str = time_str[mismatch_pos:]
+        part_to_clear: str = self.stored_time_str[mismatch_pos:]
+
+        print(f"untouched_part: {untouched_part}[{part_to_clear}-->{fresh_part}] ")
+
+        textwidth: int = self._text_width(self.stored_time_str)
+        print(f"{self.stored_time_str}: #{textwidth}")
+
+        textwidth_untouched_part: int = self._text_width(untouched_part)
+        clear_x_start_pos: int = self.xpos + textwidth_untouched_part + 1
+
+        textwidth_part_to_clear: int = self._text_width(part_to_clear)
+        clear_x_end_pos: int = clear_x_start_pos + textwidth_part_to_clear - 1
+
         self.display.clear_box(
             self.ypos,
-            self.xpos,
+            clear_x_start_pos,
             self.ypos + self.display.font_height,
-            self.xpos + self.CLOCK_WIDTH,
+            clear_x_end_pos,
-            color=colors.MAGENTA,
+            color=self.clear_color,
         )
 
         self.display.write_text(
-            time_str[:8], self.xpos, self.ypos, color=colors.NEON_YELLOW
+            fresh_part, clear_x_start_pos, self.ypos, color=self.text_color
         )
+
+        self.stored_time_str = time_str

app/utils/font_utils.py

@@ -1,5 +1,12 @@
 from .math_utils import show_byte_matrix
 
+
+def text_width(text: str, font: dict[str, list[int]]) -> int:
+    text_width_overall: int = sum([char_width(font[char]) for char in text])
+
+    return text_width_overall + len(text) - 1
+
+
 def char_width(char_matrix) -> int:
     """Berechnung der Bits für die Zeichenbreite
 
@@ -20,6 +27,7 @@ def char_width(char_matrix) -> int:
 
     return cw
 
+
 def shift_letter_right(char, letter, debug=False) -> bool:
     """Prüfe ob das Zeichen auch komplett nach rechts gezogen ist
 
@@ -59,24 +67,42 @@ def shift_letter_right(char, letter, debug=False) -> bool:
     shifted = shiftLetterRight(letter)
 
     if debug:
-		print('origin:')
+        print("origin:")
         show_byte_matrix(char, letter)
-		print('shifted')
+        print("shifted")
         show_byte_matrix(char, shifted)
 
     return shifted
 
+
 def align_font(font, debug=False):
     chars = [char for char in font]
     print(chars)
 
     # Print the dictionary
-	print('font_pretty = {')
+    print("font_pretty = {")
     for char in sorted(font.keys()):
         shifted = shift_letter_right(char=char, letter=font[char], debug=debug)
-		hex_values = [f'0x{val:02X}' for val in shifted]
+        hex_values = [f"0x{val:02X}" for val in shifted]
         print(f"\t'{char}': [{', '.join(hex_values)}],")
-	print('}')
+    print("}")
 
     # return f'#keys: {len(list(font.keys()))}'
-	return f'#keys: {len(font)}'
+    return f"#keys: {len(font)}"
+
+
+def find_first_mismatch(str1: str, str2: str) -> int:
+    """
+    Compare two strings of equal length and return the position of first mismatch.
+
+    Args:
+        str1 (str): First string
+        str2 (str): Second string (same length as str1)
+
+    Returns:
+        int: Position of first mismatch, or -1 if strings are identical
+    """
+    for i in range(len(str1)):
+        if str1[i] != str2[i]:
+            return i
+    return -1

main.py

@@ -32,9 +32,8 @@ async def print_time_task() -> None:
     digitalClock: DigitalClock = DigitalClock(display, 0, bottom_ypos)
     while True:
         dt1: str = get_datetime_string()
-        dt2: str = get_german_datetime()
         simpleCnt += 1
-        print(f"print_time_task running... {simpleCnt.value % 16} {dt1} {dt2}")
+        print(f"print_time_task running... {simpleCnt.value % 16} {dt1}")
 
         await digitalClock.tick()
         await asyncio.sleep(2)