Kivy: SizedLabel

sizedlabel.py

class SizedLabel(Label):
	max_lines = BoundedNumericProperty(3, min=1)
	sizetext = StringProperty('')
	auto_wrap = BooleanProperty(True)
	auto_height = BooleanProperty(False)
	outline_color = ListProperty([0.0] * 4)
	line_threshold = ListProperty((36, 80, 124,))
	resize_text = BooleanProperty(True)
	resize_text_down_only = BooleanProperty(False)
	
	wordsep_re = re.compile(
		r'([^\s\w]*\w+[^0-9\W] -(?=\W)|'		  # keep en-dashes
		r'\s+|'									  # any whitespace
		r'[^\s\w]*\w+[^0-9\W]-(?=\w+[^0-9\W])|'   # hyphenated words
		r'(?<=[\w\!\"\'\&\.\,\?])-{2,}(?=\w))')   # em-dash

	wordsep_re_uni = re.compile(wordsep_re.pattern, re.U)
	
	def __init__(self, **kwargs):
		super(SizedLabel, self).__init__(**kwargs)
		self.halign = 'center'
		#self.bind(on_size=self.text_size)
		self.wrapper = textwrap.TextWrapper(break_long_words=False, expand_tabs=False)
		self.trigger_sizetext = Clock.create_trigger(self.update_sizetext, -1)
		self.bind(sizetext=self.trigger_sizetext, size=self.trigger_sizetext)
		self.trigger_sizetext()

	def get_max_lines(self, height):
		height_lines = 99999
		if height < self.line_threshold[0]:
			height_lines = 1
		elif height < self.line_threshold[1]:
			height_lines = 2
		elif height < self.line_threshold[2]:
			height_lines = 3
		return min(height_lines, self.max_lines)
	
	def update_sizetext(self, *_args):
		if not self.width or not self.height:
			return

		cw = self.width - max(8, self.width * 0.08)
		ch = self.height - max(8, self.height * 0.08)
		
		text = ' '.join(self.sizetext.strip().split())
		max_lines = self.get_max_lines(ch)
		num_lines = min(max_lines, text.count(' ') + 1)

		self.text = text
		if self.resize_text:
			self.font_size = 16
		self.texture_update()
		
		if not text or not ch:
			return
		
		ts = self.texture_size
		sr = [[float(ts[0]) / ts[1], text, 1, float(ts[0]), float(ts[1])]]
		
		if self.auto_wrap and num_lines > 1:
			label = self._label
			wrapper = self.wrapper
			wrap = wrapper._wrap_chunks
			join = '\n'.join
			text = text.translate(wrapper.whitespace_trans if isinstance(text, str) else wrapper.unicode_whitespace_trans)
			stext = filter(None, (self.wordsep_re if isinstance(text, str) else self.wordsep_re_uni).split(text))
			for wrapper.width in reversed(range(int(len(text) / (num_lines + 1)), int(len(text) * 0.75 + 0.5))[1:]):
				wrapped = wrap(stext[:])
				lines = len(wrapped)
				if lines > num_lines:
					break
				ltext = join(wrapped)
				self.text = ltext
				label.refresh()
				size = label.texture.size
				sr.append([float(size[0]) / size[1], ltext, lines, size[0], size[1]])
		
		cr = float(cw) / ch
		och = ch
		
		sr = sorted(sr, key=lambda a: abs(cr - a[0]))
		
		for _i, v in enumerate(sr):
			_ratio, text, lines, width, height = v
			self.text = text
			
			if not self.auto_height:
				ch = och * (float(lines) / max_lines)
			else:
				ch = och
			
			upsize = ch / height
			if width * upsize > cw:
				# skip any options which require resizing
				continue
			self.resize_text_method(upsize)
			self.texture_update()
			return
		
		# well, there weren't any options without resizing
		_ratio, text, lines, width, height = max(sr, key=lambda a: a[2] * 2 - abs(cr - a[0]))
		self.text = text
		
		upsize = cw / width
		self.resize_text_method(upsize)
		self.texture_update()

	def resize_text_method(self, upsize):
		if upsize > 0 and self.resize_text:
			if self.resize_text_down_only:
				if upsize < 1:
					self.font_size *= upsize
			else:
				self.font_size *= upsize