Cite the data source at the foot of every chart

lib/render.py

@@ -35,6 +35,7 @@ class Chart:
 	red_rows: tuple = () # bars: the indices of rows drawn in red though they are not below zero (the sells)
 	threshold: float = None # shorts: the outrageous line
 	change: float = None # line: the change shown, whose sign colours the line and its subtitle
+	source: str = '' # where the data comes from, cited at the foot of the image ('Yahoo Finance')
 
 	@property
 	def drawable(self):
@@ -85,6 +86,7 @@ def rise_fall_flat():
 ASCENT, DESCENT = 0.76, 0.21 # its tallest letters and descenders, in ems: a line of text sits as matplotlib set it
 SLANT = 0.2 # italic: the upright face sheared by 11 degrees, as its oblique is (not in fonts-dejavu-core)
 
+_source = contextvars.ContextVar('source', default='') # draw() cites the chart's source on its canvas
 _drawing = threading.RLock() # one chart at a time: Pillow's fonts are shared by every thread
 
 def preload():
@@ -174,6 +176,8 @@ def png(self):
 		from PIL import Image, ImageDraw
 		image = self.image.reduce(self.scale) if self.scale > 1 else self.image
 		pen = ImageDraw.Draw(image)
+		if cited := _source.get():
+			self.text(0.03 * W, self.height - 0.012 * H, f"Source: {cited}", 6.5, palette()[2], va='bottom')
 		for x, baseline, line, size, color, bold, italic in self.writing:
 			if italic:
 				_slanted(image, x, baseline, line, size, color)
@@ -739,7 +743,8 @@ def draw_treemap(chart):
 	canvas = _Canvas(W, H, bg, scale=1) # upright edges alone: nothing to smooth
 	total = sum(value for _, held in rows for _, value in held) or 1.0
 	top = _plot_top(chart.subtitle) # below the heading, as the other charts are
-	box = _squarify([sum(value for _, value in held) for _, held in rows], 0, top, W, H - top) # 2px edges, with gaps
+	foot = 0.04 * H if chart.source else 0 # a strip below the tiles for the source
+	box = _squarify([sum(value for _, value in held) for _, held in rows], 0, top, W, H - top - foot) # 2px edges, gaps
 	n = 0
 	for (label, held), (x, y, w, h) in zip(rows, box):
 		color = '#6b7280' if label == 'Other' else CATEGORIES[n % len(CATEGORIES)]
@@ -798,11 +803,12 @@ def draw(chart):
 	name = f"finbot_chart_{hashlib.sha1(key.encode()).hexdigest()[:20]}.png"
 	if config.settings.cache and (image := cache.read_bytes(name, math.inf)): # kept until cleanup: it never goes stale
 		return image
-	token = _dark_now.set(dark)
+	token, cited = _dark_now.set(dark), _source.set(chart.source)
 	try:
 		image = RENDERERS[chart.kind](trimmed(chart))
 	finally:
 		_dark_now.reset(token)
+		_source.reset(cited)
 	if config.settings.cache:
 		cache.write_bytes(name, image)
 		image.seek(0)

lib/reports/history.py

@@ -40,7 +40,7 @@ def prepare_compare(service, tickers, period_days=None):
 	subtitle = f"% change over {period_label}, {formats.date_span(start, end)}" + note
 	lines = tuple((formats.short_ticker(t), tuple((f"{day:%Y-%m-%d}", float(close)) for day, close in rows))
 		for t, rows in cropped)
-	chart = render.Chart('compare', title, subtitle, lines)
+	chart = render.Chart('compare', title, subtitle, lines, source='Yahoo Finance')
 	caption = [service.bold(f"{period_label}, since {start:%-d %b %Y}") + note]
 	results = sorted(((growth(rows) - 1) * 100, t) for t, rows in cropped)
 	for pct, t in reversed(results):
@@ -63,7 +63,8 @@ def line_chart(ticker, changes, line, days=None):
 	price = ' '.join(filter(None, (formats.price(line.price), line.currency)))
 	shown = formats.date_span(*(datetime.date.fromisoformat(line.closes[end][0]) for end in (0, -1))) # its dates
 	subtitle = f"{price}   {arrow} {abs(change):,g}%   {shown}"
-	return render.Chart('line', f"{line.name} ({ticker}) {span}", subtitle, line.closes, change=float(change))
+	return render.Chart('line', f"{line.name} ({ticker}) {span}", subtitle, line.closes, change=float(change),
+		source='Yahoo Finance')
 
 def price_line(ticker, days=None, quote=None):
 	"""(its changes, its line chart or None) of a ticker over `days`, else over its whole history, to the price of its

lib/reports/holdings.py

@@ -96,7 +96,8 @@ def prepare_treemap(portfolio_name, by, service, max_groups=8):
 	count = sum(len(held) for held in groups.values())
 	subtitle = f"{_noun(by, len(groups))}, {count} {'holding' if count == 1 else 'holdings'}, " + \
 		formats.date_short(formats.today(), True)
-	return payload, render.Chart('treemap', title, subtitle, tuple((label, tuple(held)) for label, held in rows))
+	return payload, render.Chart('treemap', title, subtitle, tuple((label, tuple(held)) for label, held in rows),
+		source='Sharesight')
 
 def prepare_watchlist(service, chat, user, action=None, ticker=None, removing=()):
 	"""The .watchlist reply in a chat (by its key): the companies it watches, those of `removing` struck through, or one

lib/reports/movers.py

@@ -139,7 +139,8 @@ def report(service, found, mode='interday', threshold=None, days=None, top=None,
 	if not top:
 		heading = lambda when: HEADINGS[mode].format(threshold=threshold, when=when, where=", ".join(found.exchanges))
 		session = mode if mode in ('midsession', 'premarket') else None
-		chart = render.Chart('bars', heading(''), subtitle, tuple(label(found.rows)), session=session)
+		chart = render.Chart('bars', heading(''), subtitle, tuple(label(found.rows)), session=session,
+			source='Yahoo Finance')
 		return [service.bold(heading(f', {span}'))] + lines, chart
 	worst = [i for i in reversed(range(len(found.rows))) if i >= top][:top] # the worst, worst first, none of the best
 	payload = [service.bold(f'Top {top} movers {span}')] + lines[:top]
@@ -148,7 +149,7 @@ def report(service, found, mode='interday', threshold=None, days=None, top=None,
 	bars = label(found.rows[:top]) # the best, then after a gap the worst, the worst last
 	if worst:
 		bars += [("", None)] + label(found.rows[i] for i in reversed(worst))
-	return payload, render.Chart('bars', f"Top & bottom {top}", subtitle, tuple(bars))
+	return payload, render.Chart('bars', f"Top & bottom {top}", subtitle, tuple(bars), source='Yahoo Finance')
 
 def nothing(mode, threshold, user, ticker, in_session):
 	"""What a chat is told when nothing meets the threshold, or the one ticker asked for (.session, .premarket) has no

lib/reports/performance.py

@@ -43,7 +43,8 @@ def report(service, past_days, portfolio_select=None):
 	payload = [service.bold(f"Performance over {period}")] + [line for _, line, _ in rows]
 	chart_rows = [(label, percent) for percent, _, label in rows if percent is not None]
 	return payload, render.Chart('bars', "Performance", formats.change_span(past_days, formats.today()),
-		tuple(chart_rows), value_format='percent2')
+		tuple(chart_rows), value_format='percent2',
+		source='Sharesight, Yahoo Finance')
 
 def run(chat, *, past_days=None, portfolio_select=None):
 	"""Post each portfolio's performance over past_days (the past_days setting when None), or the one named, beside

lib/reports/rankings.py

@@ -89,7 +89,8 @@ def prepare_rating_payload(service, chat, actions, length=None, asked=True):
 	# zoom the axis onto the ratings so the bars fill the panel (ratings only run 1-5)
 	chart = render.Chart('bars', title, f"Mean rating of {analysts}: 1 = strong buy, 5 = strong sell (axis zoomed), "
 		+ formats.date_short(formats.today(), True), tuple(rows), value_format='number',
-		xlim=(max(0.9, low - spread * 0.9), min(5.1, high + spread * 0.25)), red_rows=tuple(red))
+		xlim=(max(0.9, low - spread * 0.9), min(5.1, high + spread * 0.25)), red_rows=tuple(red),
+		source='Yahoo Finance')
 	return payload, chart
 
 RATIOS = {'forward pe': 'price_to_earnings_forward', 'trailing pe': 'price_to_earnings_trailing',
@@ -146,7 +147,7 @@ def ratio_list(service, chat, kind, mode='top', length=LENGTH):
 	heading = f"{'Bottom' if mode == 'bottom' else 'Top'} {length} tracked stocks by {trail} ratio"
 	subtitle = ', '.join(filter(None, (analysts, formats.date_short(formats.today(), True))))
 	chart = render.Chart('bars', heading, subtitle, tuple((label, float(ratio)) for ratio, label, _ in rows),
-		value_format='number')
+		value_format='number', source='Yahoo Finance')
 	return [service.bold(heading + (f" ({analysts})" if analysts else ''))] + [line for _, _, line in rows], chart
 
 def prepare_beta_payload(service, chat):
@@ -165,5 +166,5 @@ def prepare_beta_payload(service, chat):
 	found.sort(key=lambda row: row[0], reverse=True)
 	heading = 'Beta over 1.5 and mkt cap under US$2B'
 	chart = render.Chart('bars', heading, formats.date_short(formats.today(), True), tuple(row for _, _, row in found),
-		value_format='number')
+		value_format='number', source='Yahoo Finance')
 	return [service.bold(heading)] + [line for _, line, _ in found], chart

lib/reports/shorts.py

@@ -53,4 +53,4 @@ def report(service, tickers, market_data, threshold, specific_stock):
 		return lines, None
 	return [service.bold(f'Tracked stocks shorted over {threshold:g}%')] + lines, render.Chart('shorts',
 		subtitle=formats.date_short(formats.today(), True), rows=tuple((code, percent) for percent, _, code in found),
-		threshold=threshold)
+		threshold=threshold, source='Short Man')

tests/test_charts.py

@@ -138,6 +138,16 @@ def test_each_chart_type(self):
 				else:
 					self.check_image(make(), name)
 
+	def test_a_chart_cites_its_source(self):
+		"""A chart with a source has it written at the foot, and still draws a sane image."""
+		plain = uncached(render.Chart('bars', 'T', 'sub', tuple(MIXED)))
+		cited = uncached(render.Chart('bars', 'T', 'sub', tuple(MIXED), source='Yahoo Finance'))
+		foot = (0, 760, 400, 800)
+		self.assertIsNotNone(ImageChops.difference(decode(plain).convert('RGB').crop(foot),
+			decode(cited).convert('RGB').crop(foot)).getbbox())
+		cited.seek(0)
+		self.check_image(cited, 'cited')
+
 	def test_edge_case_rows(self):
 		"""Rows that broke charts before (one, all zero, forty, long labels, huge or tiny values) draw sane images."""
 		for name, rows in EDGE_ROWS.items():