Issue with interpolatedFontProxy

1

It seems that I can’t get any layers from an instance that is not added to Font.instances with interpolatedFontProxy.
Example:

def make_instance(*values):
  i = GSInstance()
  i.font = Font
  for x in range(len(i.axes)):
    i.axes[x] = values[x]
  return i.interpolatedFontProxy
interpolatedFont = make_instance(50) #or any available value
print(interpolatedFont.glyphs['a'].layers[0]

would print None. Adding the instance to Font.instances fixes it, but I’d rather not do that, nor use interpolatedFont. Any idea?

2 
print(interpolatedFont.glyphs['a'].layers[interpolatedFont.fontMasterID()])

or

print(interpolatedFont.glyphs['a'].layers[interpolatedFont.masters[0].id)])

But the index should work, too. I’ll have a look.

3

The problem is that the instance gets deallocated when your function returns. So you need to store it somewhere until you are done. A global list will do the trick.

instances = []
def make_instance(*values):
  i = GSInstance()
  instances.append(i)
  i.font = Font
  for x in range(len(i.axes)):
    i.axes[x] = values[x]
  return i.interpolatedFontProxy
interpolatedFont = make_instance(50) #or any available value
print(interpolatedFont.glyphs['a'].layers[0])
2 Likes
4

Thanks Georg! I think I get the general logic behind this (the actual instance object doesn’t exist outside the scope of the function) but then, shouldn’t I just be unable to access anything via interpolatedFontProxy? I could still get some stuff, like glyphs, or the master, but just not layers.

In my particular case, I guess it’ll be easier to just have the function return the instance instead. Why didn’t I think of that before, well… ¯\(ツ)/¯

def make_instance(*values):
  i = GSInstance()
  i.font = Font
  for x in range(len(i.axes)):
    i.axes[x] = values[x]
  return i
instance = make_instance(50)
interpolatedFont = instance.interpolatedFontProxy
print(interpolatedFont.glyphs['a'].layers[0])
2 Likes
5

The proxy needs the instance now and then.

1 Like
6

I found a bug, where a color layer (either layer.isFullColorLayer() or glyph > layer.parent.isColorPaletteGlyph), when interpolated, does not have a width:

instances = []
def make_instance(*values):
  i = GSInstance()
  instances.append(i)
  i.font = Font
  for x in range(len(i.axes)):
    i.axes[x] = values[x]
  return i.interpolatedFontProxy
interpolatedFont = make_instance(50)
print(interpolatedFont.glyphs['a'].layers[0].width)

Run this on a glyph/layer that has one of these this color layer type, and it will always return 0.0

Other Layer types always have their actual width.

G 3227

Edit:
the color layer of type layer.parent.isColorPaletteGlyph(), if it is a color palette layer under a non-color layer master. Which is the proper setup, as I recon. Still wondering if that is a bug or intended.

Edit 2:
It seems I might need to dig through the .glyphMetrics() of that layer then?

However, I still only get a non-zero for the master locations. As soon as it is somewhere between, it returns 0 for the width:

instances = []
def make_instance(*values):
	i = GSInstance()
	instances.append(i)
	i.font = Font
	for x in range(len(i.axes)):
		i.axes[x] = values[x]
	return i.interpolatedFontProxy
interpolatedFont = make_instance(50)
print(interpolatedFont.glyphs['A'].layers[0].glyphMetrics()[0], "  <- BUG ❌")

interpolatedFont = make_instance(0)
print(interpolatedFont.glyphs['A'].layers[0].glyphMetrics()[0], "<- OK")

interpolatedFont = make_instance(100)
print(interpolatedFont.glyphs['A'].layers[0].glyphMetrics()[0], "<- OK")

run this code on this font:
ColorFont Width Bug.glyphs (13.4 KB)

and it will print:

0.0   <- BUG ❌
100.0 <- OK
600.0 <- OK
7

Can you reproduce this? @GeorgSeifert / @FlorianPircher

8

I got zero for all there. But I fixed it.

1 Like
9

Thanks a lot!

This fix will improve rendering of color fonts in Variable Font Preview :clap: