PyPortal.set_caption() always adds a new caption with no way to remove older ones?

[e28eta]

I am trying to update an older PyPortal-based project, and running into a set_caption issue. It used to be that there was a single label for the caption, and its text was set during PyPortal() construction, and then could be updated later using set_caption.

Here is an example project Daily UV Index PyPortal Display that calls pyportal.set_caption() on every update, which is the same basic pattern that I've been using:
https://github.com/adafruit/Adafruit_Learning_System_Guides/blob/9f6d3ea8f8b16d12c6fd3b89cd7ce5bbf0c015ec/PyPortal_UV_Index/code.py#L100-L102

Code with the bug

Today's implementation of PyPortal.set_caption always calls PortalBase.add_text(), and therefore it adds a new label every time:

Adafruit_CircuitPython_PyPortal/adafruit_pyportal/__init__.py

Lines 274 to 296 in de0b008

	def set_caption(self, caption_text, caption_position, caption_color):
	# pylint: disable=line-too-long
	"""A caption. Requires setting ``caption_font`` in init!
	:param caption_text: The text of the caption.
	:param caption_position: The position of the caption text.
	:param caption_color: The color of your caption text. Must be a hex value, e.g.
	``0x808000``.
	"""
	# pylint: enable=line-too-long
	if self._debug:
	print("Setting caption to", caption_text)
	if (not caption_text) or (not self._caption_font) or (not caption_position):
	return # nothing to do!
	index = self.add_text(
	text_position=caption_position,
	text_font=self._caption_font,
	text_color=caption_color,
	is_data=False,
	)
	self.set_text(caption_text, index)

Here's a link to the add_text implementation

Old Implementation

Looking into the source history, prior to #99, the caption label was created if needed, otherwise it was updated:

Adafruit_CircuitPython_PyPortal/adafruit_pyportal.py

Lines 586 to 618 in 88358c0

	def set_caption(self, caption_text, caption_position, caption_color):
	# pylint: disable=line-too-long
	"""A caption. Requires setting ``caption_font`` in init!
	:param caption_text: The text of the caption.
	:param caption_position: The position of the caption text.
	:param caption_color: The color of your caption text. Must be a hex value, e.g.
	``0x808000``.
	"""
	# pylint: enable=line-too-long
	if self._debug:
	print("Setting caption to", caption_text)
	if (not caption_text) or (not self._caption_font) or (not caption_position):
	return # nothing to do!
	if self._caption:
	self._caption._update_text( # pylint: disable=protected-access
	str(caption_text)
	)
	try:
	board.DISPLAY.refresh(target_frames_per_second=60)
	except AttributeError:
	board.DISPLAY.refresh_soon()
	board.DISPLAY.wait_for_frame()
	return
	self._caption = Label(self._caption_font, text=str(caption_text))
	self._caption.x = caption_position[0]
	self._caption.y = caption_position[1]
	self._caption.color = caption_color
	self.splash.append(self._caption)

This is the behavior I was used to, and is still how I'd expect it to work based on today's documentation

Workaround

I think I can workaround this by ignoring the PyPortal caption, and just managing the label myself?

Fix

I'm not sure how to approach fixing this. The interaction with PortalBase makes it a little complicated. I cloned the repo with the ambition of opening a PR, but I'm not especially familiar with how other folks are using PortalBase / PyPortal.

• could PyPortal simply remember the index of the caption? if so, how does it move the label / change the color if needed?
• should there be a way to remove labels in PortalBase, which PyPortal could use to remove / re-create the caption when needed?
• would remembering the caption label index be fragile - and prone to break if/when the fetched data needs more / fewer labels?
• should the Adafruit_Learning_System_Guides code be updated to use PyPortal class / set_caption differently?