shadowfacts/fonttools
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Document expected arguments for _TTGlyphSet, _TTGlyph and TTGlyphPen

Browse Source
This commit is contained in:
Simon Cozens 2021-02-08 11:30:39 +00:00
parent 82c32cbf88
commit 9cb126b10a
3 changed files with 43 additions and 15 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
Doc/source/ttLib/ttFont.rst
View File

@ -6,3 +6,4 @@ ttFont
:inherited-members:
:members:
:undoc-members:
:private-members:

39
Lib/fontTools/pens/ttGlyphPen.py
View File

@ -15,22 +15,34 @@ __all__ = ["TTGlyphPen"]
class TTGlyphPen(LoggingPen):
"""Pen used for drawing to a TrueType glyph.
If `handleOverflowingTransforms` is True, the components' transform values
are checked that they don't overflow the limits of a F2Dot14 number:
-2.0 <= v < +2.0. If any transform value exceeds these, the composite
glyph is decomposed.
An exception to this rule is done for values that are very close to +2.0
(both for consistency with the -2.0 case, and for the relative frequency
these occur in real fonts). When almost +2.0 values occur (and all other
values are within the range -2.0 <= x <= +2.0), they are clamped to the
maximum positive value that can still be encoded as an F2Dot14: i.e.
1.99993896484375.
If False, no check is done and all components are translated unmodified
into the glyf table, followed by an inevitable `struct.error` once an
attempt is made to compile them.
This pen can be used to construct or modify glyphs in a TrueType format
font. After using the pen to draw, use the ``.glyph()`` method to retrieve
a :py:class:`~._g_l_y_f.Glyph` object representing the glyph.
"""
def __init__(self, glyphSet, handleOverflowingTransforms=True):
"""Construct a new pen.
Args:
glyphSet (ttLib._TTGlyphSet): A glyphset object, used to resolve components.
handleOverflowingTransforms (bool): See below.
If ``handleOverflowingTransforms`` is True, the components' transform values
are checked that they don't overflow the limits of a F2Dot14 number:
-2.0 <= v < +2.0. If any transform value exceeds these, the composite
glyph is decomposed.
An exception to this rule is done for values that are very close to +2.0
(both for consistency with the -2.0 case, and for the relative frequency
these occur in real fonts). When almost +2.0 values occur (and all other
values are within the range -2.0 <= x <= +2.0), they are clamped to the
maximum positive value that can still be encoded as an F2Dot14: i.e.
1.99993896484375.
If False, no check is done and all components are translated unmodified
into the glyf table, followed by an inevitable ``struct.error`` once an
attempt is made to compile them.
"""
self.glyphSet = glyphSet
self.handleOverflowingTransforms = handleOverflowingTransforms
self.init()
@ -136,6 +148,7 @@ class TTGlyphPen(LoggingPen):
return components
def glyph(self, componentFlags=0x4):
"""Returns a :py:class:`~._g_l_y_f.Glyph` object representing the glyph."""
assert self._isClosed(), "Didn't close last contour."
components = self._buildComponents(componentFlags)

16
Lib/fontTools/ttLib/ttFont.py
View File

@ -700,6 +700,13 @@ class _TTGlyphSet(object):
"""
def __init__(self, ttFont, glyphs, glyphType):
"""Construct a new glyphset.
Args:
font (TTFont): The font object (used to get metrics).
glyphs (dict): A dictionary mapping glyph names to ``_TTGlyph`` objects.
glyphType (class): Either ``_TTGlyphCFF`` or ``_TTGlyphGlyf``.
"""
self._glyphs = glyphs
self._hmtx = ttFont['hmtx']
self._vmtx = ttFont['vmtx'] if 'vmtx' in ttFont else None
@ -740,6 +747,13 @@ class _TTGlyph(object):
"""
def __init__(self, glyphset, glyph, horizontalMetrics, verticalMetrics=None):
"""Construct a new _TTGlyph.
Args:
glyphset (_TTGlyphSet): A glyphset object used to resolve components.
glyph (ttLib.tables._g_l_y_f.Glyph): The glyph object.
horizontalMetrics (int, int): The glyph's width and left sidebearing.
"""
self._glyphset = glyphset
self._glyph = glyph
self.width, self.lsb = horizontalMetrics
@ -749,7 +763,7 @@ class _TTGlyph(object):
self.height, self.tsb = None, None
def draw(self, pen):
"""Draw the glyph onto Pen. See fontTools.pens.basePen for details
"""Draw the glyph onto ``pen``. See fontTools.pens.basePen for details
how that works.
"""
self._glyph.draw(pen)