MathGlyph() should not add offcurves just to avoid awkward situations

[LettError]

While it might solve short term compatibility problems, it really makes it difficult to prepare outlines for variable fonts.

I propose MathGlyphPen() gets a flag, something like addOffCurves=False. Then line 373 can be conditional.

[LettError]

WIP!
This needs a change in fontMath:
3557715
and probably also a change in fontParts:
robotools/fontParts@1358ecb

• a strict mathGlyph is more likely to run into compatibility problems. Currently MathGlyph falls apart in a couple of different IndexErrors, perhaps these can be wrapped better.

[benkiel]

This can now get worked on, due to #235

[Eigi]

Hello,
I'm running into the same problem as described above.
In order to solve the problem I have sub classed my fontParts RGlyph and I add the strict = True parameter to all calls of the RGlyph._toMathGlyph() method - and I add the filterRedundantPoints = False parameter to all calls of the RGlyph._fromMathGlyph() method.
Unfortunately this doesn't solve the problem. I suspect there is a bug in MathGlyph.getPointPen() method. This method ignores the strict attribute of the MathGlyph and always returns a MathGlyphPen with the default strict = False. As a result the strict = True parameter in the RGlyph._toMathGlyph() method call has no effect.

I have solved it in my fontParts RGlyph._toMathGlyph() method as follows:

    def _toMathGlyph(self, scaleComponentTransform=True, strict=False):
        """
        Subclasses may override this method.
        """
        import fontMath

        mathGlyph = fontMath.MathGlyph(
            None, scaleComponentTransform=scaleComponentTransform, strict=strict
        )
        pen = mathGlyph.getPointPen()
        pen.strict = strict
        self.drawPoints(pen)
        ...

I have manually set the strict attribute of the pen which is returned by the mathGlyph.getPointPen() call.
This solves the problem on my side but I think the mathGlyph.getPointPen() method should respect the strict attribute of the mathGlyph instance.

All the best
Eigi

[typemytype]

the mathGlyph.getPointPen() call should initiate a MathGlyphPen(self, strict=self.strict) here https://github.com/robotools/fontMath/blob/master/Lib/fontMath/mathGlyph.py#L293

could you make a PR?

thanks