Quick search

Table Of Contents

Source code for kivy.core.text


An abstraction of text creation. Depending of the selected backend, the
accuracy of text rendering may vary.

.. versionchanged:: 1.5.0
    :attr:`LabelBase.line_height` added.

.. versionchanged:: 1.0.7
    The :class:`LabelBase` does not generate any texture if the text has a
    width <= 1.

This is the backend layer for getting text out of different text providers,
you should only be using this directly if your needs aren't fulfilled by the

Usage example::

    from kivy.core.text import Label as CoreLabel

    my_label = CoreLabel()
    my_label.text = 'hello'
    # the label is usually not drawn until needed, so force it to draw.
    # Now access the texture of the label and use it wherever and
    # however you may please.
    hello_texture = my_label.texture


__all__ = ('LabelBase', 'Label')

import re
import os
from ast import literal_eval
from functools import partial
from copy import copy
from kivy import kivy_data_dir
from kivy.config import Config
from kivy.utils import platform
from kivy.graphics.texture import Texture
from kivy.core import core_select_lib
from kivy.core.text.text_layout import layout_text, LayoutWord
from kivy.resources import resource_find, resource_add_path
from kivy.compat import PY2
from kivy.setupconfig import USE_SDL2

if 'KIVY_DOC' not in os.environ:
    _default_font_paths = literal_eval(Config.get('kivy', 'default_font'))
    DEFAULT_FONT = _default_font_paths.pop(0)


whitespace_pat = re.compile('( +)')

[docs]class LabelBase(object): '''Core text label. This is the abstract class used by different backends to render text. .. warning:: The core text label can't be changed at runtime. You must recreate one. :Parameters: `font_size`: int, defaults to 12 Font size of the text `font_name`: str, defaults to DEFAULT_FONT Font name of the text `bold`: bool, defaults to False Activate "bold" text style `italic`: bool, defaults to False Activate "italic" text style `text_size`: tuple, defaults to (None, None) Add constraint to render the text (inside a bounding box). If no size is given, the label size will be set to the text size. `padding`: float, defaults to None If it's a float, it will set padding_x and padding_y `padding_x`: float, defaults to 0.0 Left/right padding `padding_y`: float, defaults to 0.0 Top/bottom padding `halign`: str, defaults to "left" Horizontal text alignment inside the bounding box `valign`: str, defaults to "bottom" Vertical text alignment inside the bounding box `shorten`: bool, defaults to False Indicate whether the label should attempt to shorten its textual contents as much as possible if a `size` is given. Setting this to True without an appropriately set size will lead to unexpected results. `shorten_from`: str, defaults to `center` The side from which we should shorten the text from, can be left, right, or center. E.g. if left, the ellipsis will appear towards the left side and it will display as much text starting from the right as possible. `split_str`: string, defaults to `' '` (space) The string to use to split the words by when shortening. If empty, we can split after every character filling up the line as much as possible. `max_lines`: int, defaults to 0 (unlimited) If set, this indicate how maximum line are allowed to render the text. Works only if a limitation on text_size is set. `mipmap`: bool, defaults to False Create a mipmap for the texture `strip`: bool, defaults to False Whether each row of text has its leading and trailing spaces stripped. If `halign` is `justify` it is implicitly True. `strip_reflow`: bool, defaults to True Whether text that has been reflowed into a second line should be stripped, even if `strip` is False. This is only in effect when `size_hint_x` is not None, because otherwise lines are never split. `unicode_errors`: str, defaults to `'replace'` How to handle unicode decode errors. Can be `'strict'`, `'replace'` or `'ignore'`. `outline_width`: int, defaults to None Width in pixels for the outline. `outline_color`: tuple, defaults to (0, 0, 0) Color of the outline. .. versionchanged:: 1.10.0 `outline_width` and `outline_color` were added. .. versionchanged:: 1.9.0 `strip`, `strip_reflow`, `shorten_from`, `split_str`, and `unicode_errors` were added. .. versionchanged:: 1.9.0 `padding_x` and `padding_y` has been fixed to work as expected. In the past, the text was padded by the negative of their values. .. versionchanged:: 1.8.0 `max_lines` parameters has been added. .. versionchanged:: 1.0.8 `size` have been deprecated and replaced with `text_size`. .. versionchanged:: 1.0.7 The `valign` is now respected. This wasn't the case previously so you might have an issue in your application if you have not considered this. ''' __slots__ = ('options', 'texture', '_label', '_text_size') _cached_lines = [] _fonts = {} _fonts_cache = {} _fonts_dirs = [] _font_dirs_files = [] _texture_1px = None def __init__( self, text='', font_size=12, font_name=DEFAULT_FONT, bold=False, italic=False, underline=False, strikethrough=False, halign='left', valign='bottom', shorten=False, text_size=None, mipmap=False, color=None, line_height=1.0, strip=False, strip_reflow=True, shorten_from='center', split_str=' ', unicode_errors='replace', font_hinting='normal', font_kerning=True, font_blended=True, outline_width=None, outline_color=None, **kwargs): # Include system fonts_dir in resource paths. # This allows us to specify a font from those dirs. LabelBase.get_system_fonts_dir() options = {'text': text, 'font_size': font_size, 'font_name': font_name, 'bold': bold, 'italic': italic, 'underline': underline, 'strikethrough': strikethrough, 'halign': halign, 'valign': valign, 'shorten': shorten, 'mipmap': mipmap, 'line_height': line_height, 'strip': strip, 'strip_reflow': strip_reflow, 'shorten_from': shorten_from, 'split_str': split_str, 'unicode_errors': unicode_errors, 'font_hinting': font_hinting, 'font_kerning': font_kerning, 'font_blended': font_blended, 'outline_width': outline_width} options['color'] = color or (1, 1, 1, 1) options['outline_color'] = outline_color or (0, 0, 0) options['padding'] = kwargs.get('padding', (0, 0)) if not isinstance(options['padding'], (list, tuple)): options['padding'] = (options['padding'], options['padding']) options['padding_x'] = kwargs.get('padding_x', options['padding'][0]) options['padding_y'] = kwargs.get('padding_y', options['padding'][1]) if 'size' in kwargs: options['text_size'] = kwargs['size'] else: if text_size is None: options['text_size'] = (None, None) else: options['text_size'] = text_size self._text_size = options['text_size'] self._text = options['text'] self._internal_size = 0, 0 # the real computed text size (inclds pad) self._cached_lines = [] self.options = options self.texture = None self.is_shortened = False self.resolve_font_name()
[docs] @staticmethod def register(name, fn_regular, fn_italic=None, fn_bold=None, fn_bolditalic=None): '''Register an alias for a Font. .. versionadded:: 1.1.0 If you're using a ttf directly, you might not be able to use the bold/italic properties of the ttf version. If the font is delivered in multiple files (one regular, one italic and one bold), then you need to register these files and use the alias instead. All the fn_regular/fn_italic/fn_bold parameters are resolved with :func:`kivy.resources.resource_find`. If fn_italic/fn_bold are None, fn_regular will be used instead. ''' fonts = [] for font_type in fn_regular, fn_italic, fn_bold, fn_bolditalic: if font_type is not None: font = resource_find(font_type) if font is None: raise IOError('File {0}s not found'.format(font_type)) else: fonts.append(font) else: fonts.append(fonts[-1]) # add regular font to list again LabelBase._fonts[name] = tuple(fonts)
def resolve_font_name(self): options = self.options fontname = options['font_name'] fonts = self._fonts fontscache = self._fonts_cache # is the font registered? if fontname in fonts: # return the preferred font for the current bold/italic combination italic = int(options['italic']) if options['bold']: bold = FONT_BOLD else: bold = FONT_REGULAR options['font_name_r'] = fonts[fontname][italic | bold] elif fontname in fontscache: options['font_name_r'] = fontscache[fontname] else: filename = resource_find(fontname) if not filename and not fontname.endswith('.ttf'): fontname = '{}.ttf'.format(fontname) filename = resource_find(fontname) if filename is None: # XXX for compatibility, check directly in the data dir filename = os.path.join(kivy_data_dir, fontname) if not os.path.exists(filename): raise IOError('Label: File %r not found' % fontname) fontscache[fontname] = filename options['font_name_r'] = filename
[docs] @staticmethod def get_system_fonts_dir(): '''Return the directories used by the system for fonts. ''' if LabelBase._fonts_dirs: return LabelBase._fonts_dirs fdirs = [] if platform == 'linux': fdirs = [ '/usr/share/fonts', '/usr/local/share/fonts', os.path.expanduser('~/.fonts'), os.path.expanduser('~/.local/share/fonts')] elif platform == 'macosx': fdirs = ['/Library/Fonts', '/System/Library/Fonts', os.path.expanduser('~/Library/Fonts')] elif platform == 'win': fdirs = [os.path.join(os.environ['SYSTEMROOT'], 'Fonts')] elif platform == 'ios': fdirs = ['/System/Library/Fonts'] elif platform == 'android': fdirs = ['/system/fonts'] else: raise Exception("Unknown platform: {}".format(platform)) fdirs.append(os.path.join(kivy_data_dir, 'fonts')) # register the font dirs rdirs = [] _font_dir_files = [] for fdir in fdirs: for _dir, dirs, files in os.walk(fdir): _font_dir_files.extend(files) resource_add_path(_dir) rdirs.append(_dir) LabelBase._fonts_dirs = rdirs LabelBase._font_dirs_files = _font_dir_files return rdirs
[docs] def get_extents(self, text): '''Return a tuple (width, height) indicating the size of the specified text''' return (0, 0)
[docs] def get_cached_extents(self): '''Returns a cached version of the :meth:`get_extents` function. :: >>> func = self._get_cached_extents() >>> func <built-in method size of pygame.font.Font object at 0x01E45650> >>> func('a line') (36, 18) .. warning:: This method returns a size measuring function that is valid for the font settings used at the time :meth:`get_cached_extents` was called. Any change in the font settings will render the returned function incorrect. You should only use this if you know what you're doing. .. versionadded:: 1.9.0 ''' return self.get_extents
def _render_begin(self): pass def _render_text(self, text, x, y): pass def _render_end(self): pass
[docs] def shorten(self, text, margin=2): ''' Shortens the text to fit into a single line by the width specified by :attr:`text_size` [0]. If :attr:`text_size` [0] is None, it returns text text unchanged. :attr:`split_str` and :attr:`shorten_from` determines how the text is shortened. :params: `text` str, the text to be shortened. `margin` int, the amount of space to leave between the margins and the text. This is in addition to :attr:`padding_x`. :returns: the text shortened to fit into a single line. ''' textwidth = self.get_cached_extents() uw = self.text_size[0] if uw is None or not text: return text opts = self.options uw = max(0, int(uw - opts['padding_x'] * 2 - margin)) # if larger, it won't fit so don't even try extents chr = type(text) text = text.replace(chr('\n'), chr(' ')) if len(text) <= uw and textwidth(text)[0] <= uw: return text c = opts['split_str'] offset = 0 if len(c) else 1 dir = opts['shorten_from'][0] elps = textwidth('...')[0] if elps > uw: self.is_shortened = True if textwidth('..')[0] <= uw: return '..' else: return '.' uw -= elps f = partial(text.find, c) f_rev = partial(text.rfind, c) # now find the first and last word e1, s2 = f(), f_rev() if dir != 'l': # center or right # no split, or the first word doesn't even fit if e1 != -1: l1 = textwidth(text[:e1])[0] l2 = textwidth(text[s2 + 1:])[0] if e1 == -1 or l1 + l2 > uw: self.is_shortened = True if len(c): opts['split_str'] = '' res = self.shorten(text, margin) opts['split_str'] = c return res # at this point we do char by char so e1 must be zero if l1 <= uw: return chr('{0}...').format(text[:e1]) return chr('...') # both word fits, and there's at least on split_str if s2 == e1: # there's only on split_str self.is_shortened = True return chr('{0}...{1}').format(text[:e1], text[s2 + 1:]) # both the first and last word fits, and they start/end at diff pos if dir == 'r': ee1 = f(e1 + 1) while l2 + textwidth(text[:ee1])[0] <= uw: e1 = ee1 if e1 == s2: break ee1 = f(e1 + 1) else: while True: if l1 <= l2: ee1 = f(e1 + 1) l1 = textwidth(text[:ee1])[0] if l2 + l1 > uw: break e1 = ee1 if e1 == s2: break else: ss2 = f_rev(0, s2 - offset) l2 = textwidth(text[ss2 + 1:])[0] if l2 + l1 > uw: break s2 = ss2 if e1 == s2: break else: # left # no split, or the last word doesn't even fit if s2 != -1: l2 = textwidth(text[s2 + (1 if len(c) else -1):])[0] l1 = textwidth(text[:max(0, e1)])[0] # if split_str if s2 == -1 or l2 + l1 > uw: self.is_shortened = True if len(c): opts['split_str'] = '' res = self.shorten(text, margin) opts['split_str'] = c return res return chr('...') # both word fits, and there's at least on split_str if s2 == e1: # there's only on split_str self.is_shortened = True return chr('{0}...{1}').format(text[:e1], text[s2 + 1:]) # both the first and last word fits, and they start/end at diff pos ss2 = f_rev(0, s2 - offset) while l1 + textwidth(text[ss2 + 1:])[0] <= uw: s2 = ss2 if s2 == e1: break ss2 = f_rev(0, s2 - offset) self.is_shortened = True return chr('{0}...{1}').format(text[:e1], text[s2 + 1:])
def _default_line_options(self, lines): for line in lines: if len(line.words): # get opts from first line, first word return line.words[0].options return None def clear_texture(self): self._render_begin() data = self._render_end() assert(data) if data is not None and data.width > 1: self.texture.blit_data(data) return def render_lines(self, lines, options, render_text, y, size): get_extents = self.get_cached_extents() uw, uh = options['text_size'] xpad = options['padding_x'] if uw is not None: uww = uw - 2 * xpad # real width of just text w = size[0] sw = options['space_width'] halign = options['halign'] split = re.split for layout_line in lines: # for plain label each line has only one str lw, lh = layout_line.w, layout_line.h line = '' assert len(layout_line.words) < 2 if len(layout_line.words): last_word = layout_line.words[0] line = last_word.text x = xpad if halign == 'center': x = int((w - lw) / 2.) elif halign == 'right': x = max(0, int(w - lw - xpad)) # right left justify # divide left over space between `spaces` # TODO implement a better method of stretching glyphs? if (uw is not None and halign == 'justify' and line and not layout_line.is_last_line): # number spaces needed to fill, and remainder n, rem = divmod(max(uww - lw, 0), sw) n = int(n) words = None if n or rem: # there's no trailing space when justify is selected words = split(whitespace_pat, line) if words is not None and len(words) > 1: space = type(line)(' ') # words: every even index is spaces, just add ltr n spaces for i in range(n): idx = (2 * i + 1) % (len(words) - 1) words[idx] = words[idx] + space if rem: # render the last word at the edge, also add it to line ext = get_extents(words[-1]) word = LayoutWord(last_word.options, ext[0], ext[1], words[-1]) layout_line.words.append(word) last_word.lw = uww - ext[0] # word was stretched render_text(words[-1], x + last_word.lw, y) last_word.text = line = ''.join(words[:-2]) else: last_word.lw = uww # word was stretched last_word.text = line = ''.join(words) layout_line.w = uww # the line occupies full width if len(line): layout_line.x = x layout_line.y = y render_text(line, x, y) y += lh return y def _render_real(self): lines = self._cached_lines options = self._default_line_options(lines) if options is None: # there was no text to render return self.clear_texture() old_opts = self.options ih = self._internal_size[1] # the real size of text, not texture size = self.size valign = options['valign'] y = ypad = options['padding_y'] # pos in the texture if valign == 'bottom': y = size[1] - ih + ypad elif valign == 'middle' or valign == 'center': y = int((size[1] - ih) / 2 + ypad) self._render_begin() self.render_lines(lines, options, self._render_text, y, size) # get data from provider data = self._render_end() assert(data) self.options = old_opts # If the text is 1px width, usually, the data is black. # Don't blit that kind of data, otherwise, you have a little black bar. if data is not None and data.width > 1: self.texture.blit_data(data)
[docs] def render(self, real=False): '''Return a tuple (width, height) to create the image with the user constraints. (width, height) includes the padding. ''' if real: return self._render_real() options = copy(self.options) options['space_width'] = self.get_extents(' ')[0] options['strip'] = strip = (options['strip'] or options['halign'] == 'justify') uw, uh = options['text_size'] = self._text_size text = self.text if strip: text = text.strip() self.is_shortened = False if uw is not None and options['shorten']: text = self.shorten(text) self._cached_lines = lines = [] if not text: return 0, 0 if uh is not None and (options['valign'] == 'middle' or options['valign'] == 'center'): center = -1 # pos of newline if len(text) > 1: middle = int(len(text) // 2) l, r = text.rfind('\n', 0, middle), text.find('\n', middle) if l != -1 and r != -1: center = l if center - l <= r - center else r elif l != -1: center = l elif r != -1: center = r # if a newline split text, render from center down and up til uh if center != -1: # layout from center down until half uh w, h, clipped = layout_text(text[center + 1:], lines, (0, 0), (uw, uh / 2), options, self.get_cached_extents(), True, True) # now layout from center upwards until uh is reached w, h, clipped = layout_text(text[:center + 1], lines, (w, h), (uw, uh), options, self.get_cached_extents(), False, True) else: # if there's no new line, layout everything w, h, clipped = layout_text(text, lines, (0, 0), (uw, None), options, self.get_cached_extents(), True, True) else: # top or bottom w, h, clipped = layout_text(text, lines, (0, 0), (uw, uh), options, self.get_cached_extents(), options['valign'] == 'top', True) self._internal_size = w, h if uw: w = uw if uh: h = uh if h > 1 and w < 2: w = 2 return int(w), int(h)
def _texture_refresh(self, *l): self.refresh() def _texture_fill(self, texture): # second pass, render for real self.render(real=True)
[docs] def refresh(self): '''Force re-rendering of the text ''' self.resolve_font_name() # first pass, calculating width/height sz = self.render() self._size_texture = sz self._size = (sz[0], sz[1]) # if no text are rendered, return nothing. width, height = self._size if width <= 1 or height <= 1: self.texture = self.texture_1px return # create a delayed texture texture = self.texture if texture is None or \ width != texture.width or \ height != texture.height: texture = Texture.create(size=(width, height), mipmap=self.options['mipmap'], callback=self._texture_fill) texture.flip_vertical() texture.add_reload_observer(self._texture_refresh) self.texture = texture else: texture.ask_update(self._texture_fill)
def _get_text(self): if PY2: try: if isinstance(self._text, unicode): return self._text return self._text.decode('utf8') except AttributeError: # python 3 support return str(self._text) except UnicodeDecodeError: return self._text else: return self._text def _set_text(self, text): if text != self._text: self._text = text text = property(_get_text, _set_text, doc='Get/Set the text') label = property(_get_text, _set_text, doc='Get/Set the text') @property def texture_1px(self): if LabelBase._texture_1px is None: tex = Texture.create(size=(1, 1), colorfmt='rgba') tex.blit_buffer(b'\x00\x00\x00\x00', colorfmt='rgba') LabelBase._texture_1px = tex return LabelBase._texture_1px @property def size(self): return self._size @property def width(self): return self._size[0] @property def height(self): return self._size[1] @property def content_width(self): '''Return the content width; i.e. the width of the text without any padding.''' if self.texture is None: return 0 return self.texture.width - 2 * self.options['padding_x'] @property def content_height(self): '''Return the content height; i.e. the height of the text without any padding.''' if self.texture is None: return 0 return self.texture.height - 2 * self.options['padding_y'] @property def content_size(self): '''Return the content size (width, height)''' if self.texture is None: return (0, 0) return (self.content_width, self.content_height) @property def fontid(self): '''Return a unique id for all font parameters''' return str([self.options[x] for x in ( 'font_size', 'font_name_r', 'bold', 'italic', 'underline', 'strikethrough')]) def _get_text_size(self): return self._text_size def _set_text_size(self, x): self._text_size = x text_size = property(_get_text_size, _set_text_size, doc='''Get/set the (width, height) of the ' 'contrained rendering box''') usersize = property(_get_text_size, _set_text_size, doc='''(deprecated) Use text_size instead.''')
# Load the appropriate provider label_libs = [] if USE_SDL2: label_libs += [('sdl2', 'text_sdl2', 'LabelSDL2')] else: label_libs += [('pygame', 'text_pygame', 'LabelPygame')] label_libs += [ ('pil', 'text_pil', 'LabelPIL')] Text = Label = core_select_lib('text', label_libs) if 'KIVY_DOC' not in os.environ: if not Label: from kivy.logger import Logger import sys Logger.critical('App: Unable to get a Text provider, abort.') sys.exit(1) # For the first initialization, register the default font Label.register(DEFAULT_FONT, *_default_font_paths)