When the system has a ttf file, the exported PDF font is type3

[loveloki]

Use SourceHanSerifSC-VF.ttf

import {Canvas, FontLibrary} from 'skia-canvas'

const family = 'Source Han Serif SC VF'

console.log(FontLibrary.family(family))

const width = 400
const height = 400
let canvas = new Canvas(width, height)
let ctx = canvas.getContext("2d")

ctx.fillStyle = "purple"
const text = "测试"
ctx.font = `normal 20pt ${family}`
ctx.fillText(text, 10, 50)

await canvas.saveAs("output.pdf")

FontLibrary output:

{
  family: 'Source Han Serif SC VF',
  weights: [
    250, 300, 400,
    500, 600, 700,
    800, 900
  ],
  widths: [ 'normal' ],
  styles: [ 'normal' ]
}

The fc-list | grep 'Source Han Serif SC VF' output:

/home/test/.fonts/SourceHanSerifSC-VF.ttf: Source Han Serif SC VF:style=Medium
/home/test/.fonts/SourceHanSerifSC-VF.ttf: Source Han Serif SC VF,思源宋体 VF:style=ExtraLight,Regular
/home/test/.fonts/SourceHanSerifSC-VF.ttf: Source Han Serif SC VF:style=SemiBold
/home/test/.fonts/SourceHanSerifSC-VF.ttf: Source Han Serif SC VF,思源宋体 VF:style=Light
/home/test/.fonts/SourceHanSerifSC-VF.ttf: Source Han Serif SC VF:style=Bold
/home/test/.fonts/SourceHanSerifSC-VF.ttf: Source Han Serif SC VF:style=Heavy
/home/test/.fonts/SourceHanSerifSC-VF.ttf: Source Han Serif SC VF

The result is a type 3 font:

Why is this result? I'm using a TTF font, I guess which should be embeddable normally

[loveloki]

Is there a way to know when fillText whether to use the given font family? If type3 fonts are used like this, it cannot be determined from the generated PDF.

[samizdatco]

According to the Skia docs, TrueType fonts will be converted to Type3 if the "do not embed" flag is set within the font's metadata. Maybe that's what's happening with your font?

[loveloki]

It looks like there not Subsetting Forbidden.

Maybe there's something about this font that skia doesn't support?