Adding ScrollingLabel

adafruit_display_text/scrolling_label.py

@@ -0,0 +1,144 @@
+# SPDX-FileCopyrightText: 2019 Scott Shawcroft for Adafruit Industries
+#
+# SPDX-License-Identifier: MIT
+
+"""
+`adafruit_display_text.scrolling_label`
+====================================================
+
+Displays text into a fixed-width label that scrolls leftward
+if the full_text is large enough to need it.
+
+* Author(s): Tim Cocks
+
+Implementation Notes
+--------------------
+
+**Hardware:**
+
+**Software and Dependencies:**
+
+* Adafruit CircuitPython firmware for the supported boards:
+  https://circuitpython.org/downloads
+
+"""
+
+__version__ = "0.0.0-auto.0"
+__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_Display_Text.git"
+
+import time
+from adafruit_display_text import bitmap_label
+
+
+class ScrollingLabel(bitmap_label.Label):
+
+    """
+    ScrollingLabel - A fixed-width label that will scroll to the left
+    in order to show the full text if it's larger than the fixed-width.
+
+    :param font: The font to use for the label.
+    :param max_characters: The number of characters that sets the  fixed-width. Default is 10.
+    :param text: The full text to show in the label. If this is longer than
+     `max_characters` then the label will scroll to show everything.
+    :param animate_time: The number of seconds in between scrolling animation
+     frames. Default is 0.3 seconds.
+    :param current_index: The index of the first visible character in the label.
+     Default is 0, the first character. Will increase while scrolling.
+    """
+
+    # pylint: disable=too-many-arguments
+    def __init__(
+        self,
+        font,
+        max_characters=10,
+        text="",
+        animate_time=0.3,
+        current_index=0,
+        **kwargs
+    ):
+
+        super().__init__(font, **kwargs)
+        self.animate_time = animate_time
+        self._current_index = current_index
+        self._last_animate_time = -1
+        self.max_characters = max_characters
+
+        if text[-1] != " ":
+            text = "{} ".format(text)
+        self._full_text = text
+
+        self.update()
+
+    def update(self, force=False):
+        """
+        Attempt to update the display. If `animate_time` has elapsed since
+        previews animation frame then move the characters over by 1 index.
+        Must be called in the main loop of user code.
+
+        :param force: whether to ignore `animation_time` and force the update. Default is False.
+        :return: None
+        """
+        _now = time.monotonic()
+        if force or self._last_animate_time + self.animate_time <= _now:
+
+            if len(self.full_text) <= self.max_characters:
+                self.text = self.full_text
+                self._last_animate_time = _now
+                return
+
+            if self.current_index + self.max_characters <= len(self.full_text):
+                _showing_string = self.full_text[
+                    self.current_index : self.current_index + self.max_characters
+                ]
+            else:
+                _showing_string_start = self.full_text[self.current_index :]
+                _showing_string_end = "{}".format(
+                    self.full_text[
+                        : (self.current_index + self.max_characters)
+                        % len(self.full_text)
+                    ]
+                )
+
+                _showing_string = "{}{}".format(
+                    _showing_string_start, _showing_string_end
+                )
+            self.text = _showing_string
+
+            self.current_index += 1
+            self._last_animate_time = _now
+
+            return
+
+    @property
+    def current_index(self):
+        """
+        Index of the first visible character.
+
+        :return int: the current index
+        """
+        return self._current_index
+
+    @current_index.setter
+    def current_index(self, new_index):
+        if new_index < len(self.full_text):
+            self._current_index = new_index
+        else:
+            self._current_index = new_index % len(self.full_text)
+
+    @property
+    def full_text(self):
+        """
+        The full text to be shown. If it's longer than `max_characters` then
+        scrolling will occur as needed.
+
+        :return string: The full text of this label.
+        """
+        return self._full_text
+
+    @full_text.setter
+    def full_text(self, new_text):
+        if new_text[-1] != " ":
+            new_text = "{} ".format(new_text)
+        self._full_text = new_text
+        self.current_index = 0
+        self.update()

examples/display_text_scrolling_label.py

@@ -0,0 +1,17 @@
+# SPDX-FileCopyrightText: 2022 Tim Cocks for Adafruit Industries
+# SPDX-License-Identifier: MIT
+
+import board
+import terminalio
+from adafruit_display_text.scrolling_label import ScrollingLabel
+
+
+text = "Hello world CircuitPython scrolling label"
+my_scrolling_label = ScrollingLabel(
+    terminalio.FONT, text=text, max_characters=20, animate_time=0.3
+)
+my_scrolling_label.x = 10
+my_scrolling_label.y = 10
+board.DISPLAY.show(my_scrolling_label)
+while True:
+    my_scrolling_label.update()