How to turn “line” segment into “curve” segment with code?

RafaŁ Buchner

this is part of my tool (for testing the code below I created the test glyph only with rectangle contour in it):

def interpolation(v1, v2, t):
    return v1 * (1 - t) + v2 * t

def interpolatePoint(p1,p2,t):
    p1x,p1y = p1.position
    p2x,p2y = p2.position
    return  interpolation(p1x, p2x, t), interpolation(p1y, p2y, t)

def turnLineIntoCubicBez(segment, contour):
    if segment.index == 0:
        prevPoint = contour.points[-1]
    else:
        prevPoint = contour.segments[segment.index - 1].points[-1]
    point = segment.points[-1]
    h1x, h1y = interpolatePoint(prevPoint,point,1/3)
    h2x, h2y = interpolatePoint(prevPoint,point,1-1/3)

    contour.insertPoint(prevPoint.index,(h1x, h1y),type="offcurve")
    contour.insertPoint(prevPoint.index,(h2x, h2y),type="offcurve")

g = CurrentGlyph()
c = g.contours[0]
s = c.segments[0]
turnLineIntoCubicBez(s, c)

It is basically meant to add offcurve points to the line segment, so the segment turns into the curve.
Ofcourse, I got an error an and RF crashes, because the segment of "line" type cannot have offcurve points. What is the best way to achieve this (line turning into the curve) in a proper way?

Best
R

frederik

don't know the context but you can also use the MathGlyphPen from fontMath to convert all line segments to curve segments

RafaŁ Buchner

@gferreira said in How to turn the "line" segment into the "curve" segment with the code?:

from variableFontGenerator import CompatibleContourPointPen

glyph = CurrentGlyph()

for contour in glyph:
pointTypes = ['curve' for segment in contour]
pen = CompatibleContourPointPen(pointTypes)
contour.drawPoints(pen)
contour.naked().clear()
pen.drawPoints(contour.naked())

Thanks Gustavo!!!
It works like a charm!

gferreira

hello @RafaŁ-Buchner,

have a look at the Batch extension source code, it has a CompatibleContourPointPen which takes a list of segment types to match.

this seems to work (you’ll need to have the Batch extension installed):

from variableFontGenerator import CompatibleContourPointPen

glyph = CurrentGlyph()

for contour in glyph:
    pointTypes = ['curve' for segment in contour]
    pen = CompatibleContourPointPen(pointTypes)
    contour.drawPoints(pen)
    contour.naked().clear()
    pen.drawPoints(contour.naked())

cheers!

RafaŁ Buchner

first thing that I can think of is to use Pen protocol to redraw whole glyph with this particular line turned into the curve, but is it the "best" way?

SOLVED How to turn “line” segment into “curve” segment with code?