Merge pull request #3146 from fonttools/drop-implied-oncurves-interpolatable
implied oncurve points for interpolatable glyphs
This commit is contained in:
Cosimo Lupo
GitHub
commit
84cebca6a1
@ -11,56 +11,13 @@ from fontTools.ttLib.tables._g_l_y_f import flagOnCurve, flagCubic
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from fontTools.ttLib.tables._g_l_y_f import Glyph
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from fontTools.ttLib.tables._g_l_y_f import GlyphComponent
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from fontTools.ttLib.tables._g_l_y_f import GlyphCoordinates
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from fontTools.ttLib.tables._g_l_y_f import dropImpliedOnCurvePoints
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import math
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__all__ = ["TTGlyphPen", "TTGlyphPointPen"]
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def drop_implied_oncurves(glyph):
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drop = set()
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start = 0
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flags = glyph.flags
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coords = glyph.coordinates
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for last in glyph.endPtsOfContours:
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for i in range(start, last + 1):
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if not (flags[i] & flagOnCurve):
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continue
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prv = i - 1 if i > start else last
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nxt = i + 1 if i < last else start
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if (flags[prv] & flagOnCurve) or flags[prv] != flags[nxt]:
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continue
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p0 = coords[prv]
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p1 = coords[i]
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p2 = coords[nxt]
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if not math.isclose(p1[0] - p0[0], p2[0] - p1[0]) or not math.isclose(
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p1[1] - p0[1], p2[1] - p1[1]
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):
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continue
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drop.add(i)
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if drop:
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# Do the actual dropping
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glyph.coordinates = GlyphCoordinates(
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coords[i] for i in range(len(coords)) if i not in drop
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)
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glyph.flags = array("B", (flags[i] for i in range(len(flags)) if i not in drop))
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endPts = glyph.endPtsOfContours
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newEndPts = []
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i = 0
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delta = 0
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for d in sorted(drop):
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while d > endPts[i]:
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newEndPts.append(endPts[i] - delta)
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i += 1
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delta += 1
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while i < len(endPts):
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newEndPts.append(endPts[i] - delta)
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i += 1
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glyph.endPtsOfContours = newEndPts
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class _TTGlyphBasePen:
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def __init__(
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self,
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@ -190,7 +147,7 @@ class _TTGlyphBasePen:
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glyph.coordinates.toInt()
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if dropImpliedOnCurves:
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drop_implied_oncurves(glyph)
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dropImpliedOnCurvePoints(glyph)
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self.init()
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@ -22,11 +22,13 @@ import sys
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import struct
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import array
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import logging
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import math
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import os
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from fontTools.misc import xmlWriter
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from fontTools.misc.filenames import userNameToFileName
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from fontTools.misc.loggingTools import deprecateFunction
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from enum import IntFlag
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from typing import Set
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log = logging.getLogger(__name__)
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@ -1530,6 +1532,85 @@ class Glyph(object):
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return result if result is NotImplemented else not result
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def dropImpliedOnCurvePoints(*interpolatable_glyphs: Glyph) -> Set[int]:
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"""Drop impliable on-curve points from the (simple) glyph or glyphs.
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In TrueType glyf outlines, on-curve points can be implied when they are located at
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the midpoint of the line connecting two consecutive off-curve points.
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If more than one glyphs are passed, these are assumed to be interpolatable masters
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of the same glyph impliable, and thus only the on-curve points that are impliable
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for all of them will actually be implied.
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The input glyph(s) is/are modified in-place.
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Args:
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interpolatable_glyphs: The glyph or glyphs to modify in-place.
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Returns:
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The set of point indices that were dropped if any.
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Reference:
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https://developer.apple.com/fonts/TrueType-Reference-Manual/RM01/Chap1.html
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"""
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assert len(interpolatable_glyphs) > 0
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drop = None
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for glyph in interpolatable_glyphs:
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may_drop = set()
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start = 0
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flags = glyph.flags
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coords = glyph.coordinates
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for last in glyph.endPtsOfContours:
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for i in range(start, last + 1):
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if not (flags[i] & flagOnCurve):
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continue
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prv = i - 1 if i > start else last
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nxt = i + 1 if i < last else start
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if (flags[prv] & flagOnCurve) or flags[prv] != flags[nxt]:
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continue
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p0 = coords[prv]
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p1 = coords[i]
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p2 = coords[nxt]
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if not math.isclose(p1[0] - p0[0], p2[0] - p1[0]) or not math.isclose(
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p1[1] - p0[1], p2[1] - p1[1]
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):
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continue
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may_drop.add(i)
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# we only want to drop if ALL interpolatable glyphs have the same implied oncurves
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if drop is None:
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drop = may_drop
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else:
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drop.intersection_update(may_drop)
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if drop:
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# Do the actual dropping
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for glyph in interpolatable_glyphs:
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coords = glyph.coordinates
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glyph.coordinates = GlyphCoordinates(
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coords[i] for i in range(len(coords)) if i not in drop
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)
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glyph.flags = array.array(
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"B", (flags[i] for i in range(len(flags)) if i not in drop)
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)
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endPts = glyph.endPtsOfContours
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newEndPts = []
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i = 0
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delta = 0
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for d in sorted(drop):
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while d > endPts[i]:
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newEndPts.append(endPts[i] - delta)
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i += 1
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delta += 1
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while i < len(endPts):
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newEndPts.append(endPts[i] - delta)
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i += 1
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glyph.endPtsOfContours = newEndPts
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return drop
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class GlyphComponent(object):
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"""Represents a component within a composite glyph.
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@ -1,5 +1,6 @@
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from fontTools.misc.fixedTools import otRound
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from fontTools.misc.testTools import getXML, parseXML
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from fontTools.misc.transform import Transform
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from fontTools.pens.ttGlyphPen import TTGlyphPen
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from fontTools.pens.recordingPen import RecordingPen, RecordingPointPen
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from fontTools.pens.pointPen import PointToSegmentPen
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@ -8,6 +9,7 @@ from fontTools.ttLib.tables._g_l_y_f import (
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Glyph,
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GlyphCoordinates,
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GlyphComponent,
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dropImpliedOnCurvePoints,
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flagOnCurve,
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flagCubic,
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ARGS_ARE_XY_VALUES,
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@ -20,6 +22,7 @@ from fontTools.ttLib.tables._g_l_y_f import (
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from fontTools.ttLib.tables import ttProgram
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import sys
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import array
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from copy import deepcopy
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from io import StringIO, BytesIO
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import itertools
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import pytest
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@ -813,6 +816,126 @@ class GlyphCubicTest:
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]
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def build_interpolatable_glyphs(contours, *transforms):
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# given a list of lists of (point, flag) tuples (one per contour), build a Glyph
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# then make len(transforms) copies transformed accordingly, and return a
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# list of such interpolatable glyphs.
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glyph1 = Glyph()
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glyph1.numberOfContours = len(contours)
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glyph1.coordinates = GlyphCoordinates(
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[pt for contour in contours for pt, _flag in contour]
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)
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glyph1.flags = array.array(
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"B", [flag for contour in contours for _pt, flag in contour]
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)
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glyph1.endPtsOfContours = [
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sum(len(contour) for contour in contours[: i + 1]) - 1
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for i in range(len(contours))
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]
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result = [glyph1]
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for t in transforms:
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glyph = deepcopy(glyph1)
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glyph.coordinates.transform((t[0:2], t[2:4]))
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glyph.coordinates.translate(t[4:6])
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result.append(glyph)
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return result
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def test_dropImpliedOnCurvePoints_all_quad_off_curves():
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# Two interpolatable glyphs with same structure, the coordinates of one are 2x the
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# other; all the on-curve points are impliable in each one, thus are dropped from
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# both, leaving contours with off-curve points only.
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glyph1, glyph2 = build_interpolatable_glyphs(
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[
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[
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((0, 1), flagOnCurve),
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((1, 1), 0),
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((1, 0), flagOnCurve),
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((1, -1), 0),
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((0, -1), flagOnCurve),
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((-1, -1), 0),
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((-1, 0), flagOnCurve),
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((-1, 1), 0),
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]
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],
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Transform().scale(2.0),
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)
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assert dropImpliedOnCurvePoints(glyph1, glyph2) == {0, 2, 4, 6}
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assert glyph1.flags == glyph2.flags == array.array("B", [0, 0, 0, 0])
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assert glyph1.coordinates == GlyphCoordinates([(1, 1), (1, -1), (-1, -1), (-1, 1)])
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assert glyph2.coordinates == GlyphCoordinates([(2, 2), (2, -2), (-2, -2), (-2, 2)])
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assert glyph1.endPtsOfContours == glyph2.endPtsOfContours == [3]
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def test_dropImpliedOnCurvePoints_all_cubic_off_curves():
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# same as above this time using cubic curves
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glyph1, glyph2 = build_interpolatable_glyphs(
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[
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[
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((0, 1), flagOnCurve),
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((1, 1), flagCubic),
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((1, 1), flagCubic),
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((1, 0), flagOnCurve),
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((1, -1), flagCubic),
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((1, -1), flagCubic),
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((0, -1), flagOnCurve),
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((-1, -1), flagCubic),
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((-1, -1), flagCubic),
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((-1, 0), flagOnCurve),
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((-1, 1), flagCubic),
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((-1, 1), flagCubic),
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]
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],
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Transform().translate(10.0),
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)
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assert dropImpliedOnCurvePoints(glyph1, glyph2) == {0, 3, 6, 9}
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assert glyph1.flags == glyph2.flags == array.array("B", [flagCubic] * 8)
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assert glyph1.coordinates == GlyphCoordinates(
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[(1, 1), (1, 1), (1, -1), (1, -1), (-1, -1), (-1, -1), (-1, 1), (-1, 1)]
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)
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assert glyph2.coordinates == GlyphCoordinates(
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[(11, 1), (11, 1), (11, -1), (11, -1), (9, -1), (9, -1), (9, 1), (9, 1)]
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)
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assert glyph1.endPtsOfContours == glyph2.endPtsOfContours == [7]
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def test_dropImpliedOnCurvePoints_not_all_impliable():
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# same input as in in test_dropImpliedOnCurvePoints_all_quad_off_curves but we
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# perturbate one of the glyphs such that the 2nd on-curve is no longer half-way
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# between the neighboring off-curves.
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glyph1, glyph2, glyph3 = build_interpolatable_glyphs(
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[
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[
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((0, 1), flagOnCurve),
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((1, 1), 0),
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((1, 0), flagOnCurve),
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((1, -1), 0),
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((0, -1), flagOnCurve),
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((-1, -1), 0),
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((-1, 0), flagOnCurve),
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((-1, 1), 0),
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]
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],
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Transform().translate(10.0),
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Transform().translate(10.0).scale(2.0),
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)
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p2 = glyph2.coordinates[2]
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glyph2.coordinates[2] = (p2[0] + 2.0, p2[1] - 2.0)
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assert dropImpliedOnCurvePoints(glyph1, glyph2, glyph3) == {
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0,
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# 2, this is NOT implied because it's no longer impliable for all glyphs
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4,
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6,
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}
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assert glyph2.flags == array.array("B", [0, flagOnCurve, 0, 0, 0])
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if __name__ == "__main__":
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import sys
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