[glyf] Support cubic curves
https://github.com/harfbuzz/boring-expansion-spec/issues/41
This commit is contained in:
Behdad Esfahbod
parent
085b489012
commit
82e0536beb
@ -7,7 +7,7 @@ from fontTools.misc.roundTools import otRound
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from fontTools.pens.basePen import LoggingPen, PenError
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from fontTools.pens.transformPen import TransformPen, TransformPointPen
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from fontTools.ttLib.tables import ttProgram
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from fontTools.ttLib.tables._g_l_y_f import flagOnCurve
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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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@ -220,9 +220,9 @@ class TTGlyphPen(_TTGlyphBasePen, LoggingPen):
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super().__init__(glyphSet, handleOverflowingTransforms)
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self.outputImpliedClosingLine = outputImpliedClosingLine
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def _addPoint(self, pt: Tuple[float, float], onCurve: int) -> None:
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def _addPoint(self, pt: Tuple[float, float], tp: int) -> None:
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self.points.append(pt)
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self.types.append(onCurve)
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self.types.append(tp)
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def _popPoint(self) -> None:
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self.points.pop()
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@ -234,15 +234,21 @@ class TTGlyphPen(_TTGlyphBasePen, LoggingPen):
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)
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def lineTo(self, pt: Tuple[float, float]) -> None:
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self._addPoint(pt, 1)
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self._addPoint(pt, flagOnCurve)
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def moveTo(self, pt: Tuple[float, float]) -> None:
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if not self._isClosed():
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raise PenError('"move"-type point must begin a new contour.')
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self._addPoint(pt, 1)
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self._addPoint(pt, flagOnCurve)
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def curveTo(self, *points) -> None:
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raise NotImplementedError
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assert len(points) % 2 == 1
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for pt in points[:-1]:
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self._addPoint(pt, flagCubic)
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# last point is None if there are no on-curve points
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if points[-1] is not None:
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self._addPoint(points[-1], 1)
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def qCurveTo(self, *points) -> None:
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assert len(points) >= 1
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@ -313,9 +319,23 @@ class TTGlyphPointPen(_TTGlyphBasePen, LogMixin, AbstractPointPen):
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raise PenError("Contour is already closed.")
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if self._currentContourStartIndex == len(self.points):
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raise PenError("Tried to end an empty contour.")
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contourStart = self.endPts[-1] + 1 if self.endPts else 0
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self.endPts.append(len(self.points) - 1)
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self._currentContourStartIndex = None
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# Resolve types for any cubic segments
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flags = self.types
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for i in range(contourStart, len(flags)):
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if flags[i] == "curve":
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j = i - 1
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if j < contourStart:
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j = len(flags) - 1
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while flags[j] == 0:
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flags[j] = flagCubic
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j -= 1
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flags[i] = flagOnCurve
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def addPoint(
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self,
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pt: Tuple[float, float],
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@ -331,11 +351,13 @@ class TTGlyphPointPen(_TTGlyphBasePen, LogMixin, AbstractPointPen):
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if self._isClosed():
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raise PenError("Can't add a point to a closed contour.")
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if segmentType is None:
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self.types.append(0) # offcurve
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elif segmentType in ("qcurve", "line", "move"):
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self.types.append(1) # oncurve
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self.types.append(0)
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elif segmentType in ("line", "move"):
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self.types.append(flagOnCurve)
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elif segmentType == "qcurve":
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self.types.append(flagOnCurve)
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elif segmentType == "curve":
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raise NotImplementedError("cubic curves are not supported")
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self.types.append("curve")
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else:
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raise AssertionError(segmentType)
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@ -569,10 +569,10 @@ flagRepeat = 0x08
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flagXsame = 0x10
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flagYsame = 0x20
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flagOverlapSimple = 0x40
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flagReserved = 0x80
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flagCubic = 0x80
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# These flags are kept for XML output after decompiling the coordinates
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keepFlags = flagOnCurve + flagOverlapSimple
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keepFlags = flagOnCurve + flagOverlapSimple + flagCubic
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_flagSignBytes = {
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0: 2,
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@ -764,6 +764,8 @@ class Glyph(object):
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if self.flags[j] & flagOverlapSimple:
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# Apple's rasterizer uses flagOverlapSimple in the first contour/first pt to flag glyphs that contain overlapping contours
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attrs.append(("overlap", 1))
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if self.flags[j] & flagCubic:
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attrs.append(("cubic", 1))
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writer.simpletag("pt", attrs)
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writer.newline()
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last = self.endPtsOfContours[i] + 1
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@ -797,6 +799,8 @@ class Glyph(object):
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flag = bool(safeEval(attrs["on"]))
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if "overlap" in attrs and bool(safeEval(attrs["overlap"])):
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flag |= flagOverlapSimple
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if "cubic" in attrs and bool(safeEval(attrs["cubic"])):
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flag |= flagCubic
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flags.append(flag)
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if not hasattr(self, "coordinates"):
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self.coordinates = coordinates
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@ -1416,20 +1420,27 @@ class Glyph(object):
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end = end + 1
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contour = coordinates[start:end]
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cFlags = [flagOnCurve & f for f in flags[start:end]]
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cuFlags = [flagCubic & f for f in flags[start:end]]
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start = end
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if 1 not in cFlags:
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# There is not a single on-curve point on the curve,
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# use pen.qCurveTo's special case by specifying None
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# as the on-curve point.
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contour.append(None)
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assert all(cuFlags) or not any(cuFlags)
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cubic = all(cuFlags)
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if cubic:
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pen.curveTo(*contour)
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else:
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pen.qCurveTo(*contour)
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else:
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# Shuffle the points so that contour the is guaranteed
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# Shuffle the points so that the contour is guaranteed
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# to *end* in an on-curve point, which we'll use for
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# the moveTo.
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firstOnCurve = cFlags.index(1) + 1
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contour = contour[firstOnCurve:] + contour[:firstOnCurve]
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cFlags = cFlags[firstOnCurve:] + cFlags[:firstOnCurve]
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cuFlags = cuFlags[firstOnCurve:] + cuFlags[:firstOnCurve]
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pen.moveTo(contour[-1])
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while contour:
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nextOnCurve = cFlags.index(1) + 1
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@ -1438,10 +1449,23 @@ class Glyph(object):
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# pen.closePath()
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if len(contour) > 1:
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pen.lineTo(contour[0])
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else:
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cubicFlags = [f for f in cuFlags[: nextOnCurve - 1]]
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assert all(cubicFlags) or not any(cubicFlags)
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cubic = any(cubicFlags)
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if cubic:
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assert all(
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cubicFlags
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), "Mixed segments not currently supported"
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assert (
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len(cubicFlags) == 2
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), "Cubic multi-segments not currently supported"
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pen.curveTo(*contour[:nextOnCurve])
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else:
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pen.qCurveTo(*contour[:nextOnCurve])
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contour = contour[nextOnCurve:]
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cFlags = cFlags[nextOnCurve:]
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cuFlags = cuFlags[nextOnCurve:]
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pen.closePath()
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def drawPoints(self, pen, glyfTable, offset=0):
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@ -1474,7 +1498,7 @@ class Glyph(object):
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segmentType = "line"
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else:
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pen.addPoint(pt)
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segmentType = "qcurve"
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segmentType = "curve" if cFlags[i] & flagCubic else "qcurve"
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pen.endPath()
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def __eq__(self, other):
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@ -332,11 +332,11 @@ class TTGlyphPointPenTest(TTGlyphPenTestBase):
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assert glyph.numberOfContours == 1
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assert glyph.endPtsOfContours == [3]
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def test_addPoint_errorOnCurve(self):
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def test_addPoint_noErrorOnCurve(self):
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pen = TTGlyphPointPen(None)
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pen.beginPath()
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with pytest.raises(NotImplementedError):
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pen.addPoint((0, 0), "curve")
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pen.endPath()
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def test_beginPath_beginPathOnOpenPath(self):
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pen = TTGlyphPointPen(None)
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