fonttools/Lib/fontTools/fontbuilder.py example code not working for .ttf output

[ThomasBHickey]

The example code in fontbuilder.py for .otf files appears to work (I'm running Ubuntu 20.04 LTS and displaying/installing the gnereated font files in Windows 10), but the very similar code for .ttf generates a font, but the glyph just appears as a rectangle and modifying the drawTestGlyph function doesn't have any effect. I went back to a version of fontbuilder.py from 2 years ago and had the same problem with the .ttf code.

I'm new to fontbuilder and have no idea how to fix this, but it is getting in my way to use it to build fonts from scratch, which I wanted to do in ttf.

--Th

[justvanrossum]

The demo code in fontBuilder.py works just fine for me. Can you perhaps post a snippet that doesn't work as expected?

[ThomasBHickey]

Sure. Here are two files, each slightly modified from the example code in fontBuilder.py to make it obvious that the blobs are actually being drawn, not some sort of default.
First, the otf code (that works):

from fontTools.fontBuilder import FontBuilder
from fontTools.pens.t2CharStringPen import T2CharStringPen

def drawTestGlyph(pen):
    pen.moveTo((100, -100))
    pen.lineTo((100, 500))
    pen.curveTo((200, 900), (400, 900), (500, 1000))
    pen.lineTo((500, -100))
    pen.closePath()


fb = FontBuilder(1024, isTTF=False)
fb.setupGlyphOrder([".notdef", ".null", "space", "A", "a"])
fb.setupCharacterMap({32: "space", 65: "A", 97: "a"})
advanceWidths = {".notdef": 600, "space": 500, "A": 600, "a": 600, ".null": 0}

familyName = "HelloTestFont"
styleName = "TotallyNormal"
version = "0.1"

nameStrings = dict(
    familyName=dict(en=familyName, nl="HalloTestFont"),
    styleName=dict(en=styleName, nl="TotaalNormaal"),
    uniqueFontIdentifier="fontBuilder: " + familyName + "." + styleName,
    fullName=familyName + "-" + styleName,
    psName=familyName + "-" + styleName,
    version="Version " + version,
)

pen = T2CharStringPen(600, None)
drawTestGlyph(pen)
charString = pen.getCharString()
charStrings = {
    ".notdef": charString,
    "space": charString,
    "A": charString,
    "a": charString,
    ".null": charString,
}
fb.setupCFF(nameStrings["psName"], {"FullName": nameStrings["psName"]}, charStrings, {})
lsb = {gn: cs.calcBounds(None)[0] for gn, cs in charStrings.items()}
metrics = {}
for gn, advanceWidth in advanceWidths.items():
    metrics[gn] = (advanceWidth, lsb[gn])
fb.setupHorizontalMetrics(metrics)
fb.setupHorizontalHeader(ascent=824, descent=200)
fb.setupNameTable(nameStrings)
fb.setupOS2(sTypoAscender=824, usWinAscent=824, usWinDescent=200)
fb.setupPost()
fb.save("test.otf")

and here is the ttf code that isn't working for me (executes and builds a .ttf file Windows recognizes, but the defined char shapes are wrong):

from fontTools.fontBuilder import FontBuilder
from fontTools.pens.ttGlyphPen import TTGlyphPen

def drawTestGlyph(pen):
    pen.moveTo((100, -100))
    pen.lineTo((100, 500))
    pen.qCurveTo((200, 900), (400, 900), (500, 1000))
    pen.lineTo((500, -100))
    pen.closePath()


fb = FontBuilder(1024, isTTF=True)
fb.setupGlyphOrder([".notdef", ".null", "space", "A", "a"])
fb.setupCharacterMap({32: "space", 65: "A", 97: "a"})
advanceWidths = {".notdef": 600, "space": 500, "A": 600, "a": 600, ".null": 0}

familyName = "HelloTestFont"
styleName = "TotallyNormal"
version = "0.1"

nameStrings = dict(
    familyName=dict(en=familyName, nl="HalloTestFont"),
    styleName=dict(en=styleName, nl="TotaalNormaal"),
    uniqueFontIdentifier="fontBuilder: " + familyName + "." + styleName,
    fullName=familyName + "-" + styleName,
    psName=familyName + "-" + styleName,
    version="Version " + version,
)

pen = TTGlyphPen(None)
drawTestGlyph(pen)
glyph = pen.glyph()
glyphs = {".notdef": glyph, "space": glyph, "A": glyph, "a": glyph, ".null": glyph}
fb.setupGlyf(glyphs)
metrics = {}
glyphTable = fb.font["glyf"]
for gn, advanceWidth in advanceWidths.items():
    metrics[gn] = (advanceWidth, glyphTable[gn].xMin)
fb.setupHorizontalMetrics(metrics)
fb.setupHorizontalHeader(ascent=824, descent=-200)
fb.setupNameTable(nameStrings)
fb.setupOS2(sTypoAscender=824, usWinAscent=824, usWinDescent=200)
fb.setupPost()
fb.save("test.ttf")

Hope you see the same thing I do. Thanks for looking at this!
--Th

[justvanrossum]

(I took the liberty to edit your comment to get the right code formatting)

[justvanrossum]

The glyphs look this this for me in FontGoggles:

Which matches exactly what drawTestGlyph() does.

Depending on the viewing platform, it is possible things get clipped weirdly if values in hhea and/or OS/2 are set up wrong.

[ThomasBHickey]

Thanks for editing the comment! Sorry to bother you, turns out to be how I was looking at the ttf file.