161 lines
5.1 KiB
Python
161 lines
5.1 KiB
Python
# SPDX-FileCopyrightText: 2019 Scott Shawcroft for Adafruit Industries
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#
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# SPDX-License-Identifier: MIT
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"""
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`adafruit_display_text.scrolling_label`
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====================================================
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Displays text into a fixed-width label that scrolls leftward
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if the full_text is large enough to need it.
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* Author(s): Tim Cocks
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Implementation Notes
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--------------------
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**Hardware:**
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**Software and Dependencies:**
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* Adafruit CircuitPython firmware for the supported boards:
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https://circuitpython.org/downloads
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"""
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__version__ = "3.2.2"
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__repo__ = "https://github.com/adafruit/Adafruit_CircuitPython_Display_Text.git"
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import adafruit_ticks
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from adafruit_display_text import bitmap_label
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try:
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from typing import Optional
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from fontio import FontProtocol
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except ImportError:
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pass
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class ScrollingLabel(bitmap_label.Label):
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"""ScrollingLabel - A fixed-width label that will scroll to the left
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in order to show the full text if it's larger than the fixed-width.
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:param font: The font to use for the label.
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:type: ~fontio.FontProtocol
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:param int max_characters: The number of characters that sets the fixed-width. Default is 10.
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:param str text: The full text to show in the label. If this is longer than
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``max_characters`` then the label will scroll to show everything.
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:param float animate_time: The number of seconds in between scrolling animation
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frames. Default is 0.3 seconds.
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:param int current_index: The index of the first visible character in the label.
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Default is 0, the first character. Will increase while scrolling."""
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# pylint: disable=too-many-arguments
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def __init__(
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self,
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font: FontProtocol,
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max_characters: int = 10,
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text: Optional[str] = "",
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animate_time: Optional[float] = 0.3,
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current_index: Optional[int] = 0,
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**kwargs
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) -> None:
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super().__init__(font, **kwargs)
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self.animate_time = animate_time
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self._current_index = current_index
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self._last_animate_time = -1
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self.max_characters = max_characters
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if text and text[-1] != " ":
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text = "{} ".format(text)
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self._full_text = text
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self.update()
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def update(self, force: bool = False) -> None:
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"""Attempt to update the display. If ``animate_time`` has elapsed since
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previews animation frame then move the characters over by 1 index.
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Must be called in the main loop of user code.
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:param bool force: whether to ignore ``animation_time`` and force the update.
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Default is False.
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:return: None
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"""
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_now = adafruit_ticks.ticks_ms()
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if force or adafruit_ticks.ticks_less(
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self._last_animate_time + int(self.animate_time * 1000), _now
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):
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if len(self.full_text) <= self.max_characters:
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if self._text != self.full_text:
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super()._set_text(self.full_text, self.scale)
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self._last_animate_time = _now
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return
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if self.current_index + self.max_characters <= len(self.full_text):
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_showing_string = self.full_text[
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self.current_index : self.current_index + self.max_characters
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]
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else:
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_showing_string_start = self.full_text[self.current_index :]
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_showing_string_end = "{}".format(
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self.full_text[
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: (self.current_index + self.max_characters)
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% len(self.full_text)
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]
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)
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_showing_string = "{}{}".format(
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_showing_string_start, _showing_string_end
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)
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super()._set_text(_showing_string, self.scale)
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self.current_index += 1
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self._last_animate_time = _now
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return
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@property
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def current_index(self) -> int:
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"""Index of the first visible character.
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:return int: The current index
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"""
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return self._current_index
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@current_index.setter
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def current_index(self, new_index: int) -> None:
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if self.full_text:
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self._current_index = new_index % len(self.full_text)
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else:
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self._current_index = 0
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@property
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def full_text(self) -> str:
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"""The full text to be shown. If it's longer than ``max_characters`` then
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scrolling will occur as needed.
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:return str: The full text of this label.
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"""
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return self._full_text
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@full_text.setter
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def full_text(self, new_text: str) -> None:
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if new_text and new_text[-1] != " ":
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new_text = "{} ".format(new_text)
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if new_text != self._full_text:
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self._full_text = new_text
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self.current_index = 0
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self.update(True)
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@property
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def text(self):
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"""The full text to be shown. If it's longer than ``max_characters`` then
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scrolling will occur as needed.
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:return str: The full text of this label.
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"""
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return self.full_text
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@text.setter
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def text(self, new_text):
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self.full_text = new_text
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