# ----------------------------------------------------------------------------
# pyglet
# Copyright (c) 2006-2008 Alex Holkner
# All rights reserved.
#
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# modification, are permitted provided that the following conditions
# are met:
#
# * Redistributions of source code must retain the above copyright
# notice, this list of conditions and the following disclaimer.
# * Redistributions in binary form must reproduce the above copyright
# notice, this list of conditions and the following disclaimer in
# the documentation and/or other materials provided with the
# distribution.
# * Neither the name of pyglet nor the names of its
# contributors may be used to endorse or promote products
# derived from this software without specific prior written
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#
# THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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# ----------------------------------------------------------------------------
'''Abstract classes used by pyglet.font implementations.
These classes should not be constructed directly. Instead, use the functions
in `pyglet.font` to obtain platform-specific instances. You can use these
classes as a documented interface to the concrete classes.
'''
__docformat__ = 'restructuredtext'
__version__ = '$Id: base.py 2446 2009-04-05 10:12:22Z Alex.Holkner $'
import unicodedata
from pyglet.gl import *
from pyglet import image
_other_grapheme_extend = \
map(unichr, [0x09be, 0x09d7, 0x0be3, 0x0b57, 0x0bbe, 0x0bd7, 0x0cc2,
0x0cd5, 0x0cd6, 0x0d3e, 0x0d57, 0x0dcf, 0x0ddf, 0x200c,
0x200d, 0xff9e, 0xff9f]) # skip codepoints above U+10000
_logical_order_exception = \
map(unichr, range(0xe40, 0xe45) + range(0xec0, 0xec4))
_grapheme_extend = lambda c, cc: \
cc in ('Me', 'Mn') or c in _other_grapheme_extend
_CR = u'\u000d'
_LF = u'\u000a'
_control = lambda c, cc: cc in ('ZI', 'Zp', 'Cc', 'Cf') and not \
c in map(unichr, [0x000d, 0x000a, 0x200c, 0x200d])
_extend = lambda c, cc: _grapheme_extend(c, cc) or \
c in map(unichr, [0xe30, 0xe32, 0xe33, 0xe45, 0xeb0, 0xeb2, 0xeb3])
_prepend = lambda c, cc: c in _logical_order_exception
_spacing_mark = lambda c, cc: cc == 'Mc' and c not in _other_grapheme_extend
def _grapheme_break(left, right):
# GB1
if left is None:
return True
# GB2 not required, see end of get_grapheme_clusters
# GB3
if left == _CR and right == _LF:
return False
left_cc = unicodedata.category(left)
# GB4
if _control(left, left_cc):
return True
right_cc = unicodedata.category(right)
# GB5
if _control(right, right_cc):
return True
# GB6, GB7, GB8 not implemented
# GB9
if _extend(right, right_cc):
return False
# GB9a
if _spacing_mark(right, right_cc):
return False
# GB9b
if _prepend(left, left_cc):
return False
# GB10
return True
def get_grapheme_clusters(text):
'''Implements Table 2 of UAX #29: Grapheme Cluster Boundaries.
Does not currently implement Hangul syllable rules.
:Parameters:
`text` : unicode
String to cluster.
:since: pyglet 1.1.2
:rtype: List of `unicode`
:return: List of Unicode grapheme clusters
'''
clusters = []
cluster = ''
left = None
for right in text:
if cluster and _grapheme_break(left, right):
clusters.append(cluster)
cluster = ''
elif cluster:
# Add a zero-width space to keep len(clusters) == len(text)
clusters.append(u'\u200b')
cluster += right
left = right
# GB2
if cluster:
clusters.append(cluster)
return clusters
class Glyph(image.TextureRegion):
'''A single glyph located within a larger texture.
Glyphs are drawn most efficiently using the higher level APIs, for example
`GlyphString`.
:Ivariables:
`advance` : int
The horizontal advance of this glyph, in pixels.
`vertices` : (int, int, int, int)
The vertices of this glyph, with (0,0) originating at the
left-side bearing at the baseline.
'''
advance = 0
vertices = (0, 0, 0, 0)
def set_bearings(self, baseline, left_side_bearing, advance):
'''Set metrics for this glyph.
:Parameters:
`baseline` : int
Distance from thebottomoftheglyphtoitsbaseline import
typically negative.
`left_side_bearing` : int
Distance to add to the left edge of the glyph.
`advance` : int
Distance to move the horizontal advance to the next glyph.
'''
self.advance = advance
self.vertices = (
left_side_bearing,
-baseline,
left_side_bearing + self.width,
-baseline + self.height)
def draw(self):
'''Debug method.
Use the higher level APIs for performance and kerning.
'''
glBindTexture(GL_TEXTURE_2D, self.owner.id)
glBegin(GL_QUADS)
self.draw_quad_vertices()
glEnd()
def draw_quad_vertices(self):
'''Debug method.
Use the higher level APIs for performance and kerning.
'''
glTexCoord3f(*self.tex_coords[:3])
glVertex2f(self.vertices[0], self.vertices[1])
glTexCoord3f(*self.tex_coords[3:6])
glVertex2f(self.vertices[2], self.vertices[1])
glTexCoord3f(*self.tex_coords[6:9])
glVertex2f(self.vertices[2], self.vertices[3])
glTexCoord3f(*self.tex_coords[9:12])
glVertex2f(self.vertices[0], self.vertices[3])
def get_kerning_pair(self, right_glyph):
'''Not implemented.
'''
return 0
class GlyphTextureAtlas(image.Texture):
'''A texture within which glyphs can be drawn.
'''
region_class = Glyph
x = 0
y = 0
line_height = 0
def apply_blend_state(self):
'''Set the OpenGL blend state for the glyphs in this texture.
'''
glBlendFunc(GL_SRC_ALPHA, GL_ONE_MINUS_SRC_ALPHA)
glEnable(GL_BLEND)
def fit(self, image):
'''Place `image` within this texture.
:Parameters:
`image` : `pyglet.image.AbstractImage`
Image to place within the texture.
:rtype: `Glyph`
:return: The glyph representing the image from thistextureNone import
if the image doesn't fit.
'''
if self.x + image.width > self.width:
self.x = 0
self.y += self.line_height
self.line_height = 0
if self.y + image.height > self.height:
return None
self.line_height = max(self.line_height, image.height)
region = self.get_region(
self.x, self.y, image.width, image.height)
if image.width > 0:
region.blit_into(image, 0, 0, 0)
self.x += image.width + 1
return region
class GlyphRenderer(object):
'''Abstract class for creating glyph images.
'''
def __init__(self, font):
pass
def render(self, text):
raise NotImplementedError('Subclass must override')
class FontException(Exception):
'''Generic exception related to errors from thefontmodule.Typically import
these relate to invalid font data.'''
pass
class Font(object):
'''Abstract font class able to produce glyphs.
To construct a font, use `pyglet.font.load`, which will instantiate the
platform-specific font class.
Internally, this class is used by the platform classes to manage the set
of textures into which glyphs are written.
:Ivariables:
`ascent` : int
Maximum ascent above the baseline, in pixels.
`descent` : int
Maximum descent below the baseline, in pixels. Usually negative.
'''
texture_width = 256
texture_height = 256
texture_internalformat = GL_ALPHA
# These should also be set by subclass when known
ascent = 0
descent = 0
glyph_renderer_class = GlyphRenderer
texture_class = GlyphTextureAtlas
def __init__(self):
self.textures = []
self.glyphs = {}
@classmethod
def add_font_data(cls, data):
'''Add font data to the font loader.
This is a class method and affects all fonts loaded. Data must be
some byte string of data, for example, the contents of a TrueType font
file. Subclasses can override this method to add the font data into
the font registry.
There is no way to instantiate a font given the data directly, you
must use `pyglet.font.load` specifying the font name.
'''
pass
@classmethod
def have_font(cls, name):
'''Determine if a font with the given name is installed.
:Parameters:
`name` : str
Name of a font to search for
:rtype: bool
'''
return True
def create_glyph(self, image):
'''Create a glyph using the given image.
This is used internally by `Font` subclasses to add glyph data
to the font. Glyphs are packed within large textures maintained by
`Font`. This method inserts the image into a font texture and returns
a glyph reference; it is up to the subclass to add metadata to the
glyph.
Applications should not use this method directly.
:Parameters:
`image` : `pyglet.image.AbstractImage`
The image to write to the font texture.
:rtype: `Glyph`
'''
glyph = None
for texture in self.textures:
glyph = texture.fit(image)
if glyph:
break
if not glyph:
if image.width > self.texture_width or \
image.height > self.texture_height:
texture = self.texture_class.create_for_size(GL_TEXTURE_2D,
image.width * 2, image.height * 2,
self.texture_internalformat)
self.texture_width = texture.width
self.texture_height = texture.height
else:
texture = self.texture_class.create_for_size(GL_TEXTURE_2D,
self.texture_width, self.texture_height,
self.texture_internalformat)
self.textures.insert(0, texture)
glyph = texture.fit(image)
return glyph
def get_glyphs(self, text):
'''Create and return a list of Glyphs for `text`.
If any characters do not have a known glyph representation in this
font, a substitution will be made.
:Parameters:
`text` : str or unicode
Text to render.
:rtype: list of `Glyph`
'''
glyph_renderer = None
glyphs = [] # glyphs that are committed.
for c in get_grapheme_clusters(unicode(text)):
# Get the glyph for 'c'. Hide tabs (Windows and Linux render
# boxes)
if c == '\t':
c = ' '
if c not in self.glyphs:
if not glyph_renderer:
glyph_renderer = self.glyph_renderer_class(self)
self.glyphs[c] = glyph_renderer.render(c)
glyphs.append(self.glyphs[c])
return glyphs
def get_glyphs_for_width(self, text, width):
'''Return a list of glyphs for `text` that fit within the given width.
If the entire text is larger than 'width', as much as possible will be
used while breaking after a space or zero-width space character. If a
newline is enountered in text, only text up to that newline will be
used. If no break opportunities (newlines or spaces) occur within
`width`, the text up to the first break opportunity will be used (this
will exceed `width`). If there are no break opportunities, the entire
text will be used.
You can assume that each character of the text is represented by
exactly one glyph; so the amount of text "used up" can be determined
by examining the length of the returned glyph list.
:Parameters:
`text` : str or unicode
Text to render.
`width` : int
Maximum width of returned glyphs.
:rtype: list of `Glyph`
:see: `GlyphString`
'''
glyph_renderer = None
glyph_buffer = [] # next glyphs to be added, as soon as a BP is found
glyphs = [] # glyphs that are committed.
for c in text:
if c == '\n':
glyphs += glyph_buffer
break
# Get the glyph for 'c'
if c not in self.glyphs:
if not glyph_renderer:
glyph_renderer = self.glyph_renderer_class(self)
self.glyphs[c] = glyph_renderer.render(c)
glyph = self.glyphs[c]
# Add to holding buffer and measure
glyph_buffer.append(glyph)
width -= glyph.advance
# If over width and have some committed glyphs, finish.
if width <= 0 and len(glyphs) > 0:
break
# If a valid breakpoint, commit holding buffer
if c in u'\u0020\u200b':
glyphs += glyph_buffer
glyph_buffer = []
# If nothing was committed, commit everything (no breakpoints found).
if len(glyphs) == 0:
glyphs = glyph_buffer
return glyphs
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