Text metrics

[deviator]

I think base render api must provide functions for getting metrics of text with selected style (font, size etc) like a width and height of string (may be more metrics).

FreeType provides width, height, horiBearingX, horiBearingY, horiAdvance, vertBearingX, vertBearingY, vertAdvance about glyph.
https://www.freetype.org/freetype2/docs/tutorial/step2.html

It's useful for develop highlevel libraries for example for rendering TeX formulas, tables with text and etc.

[p0nce]

Yes indeed the rendering context should give back text metrics.
We should look at the Canvas API not FreeType imo, since PDF and SVG use the right bearing, horizontal advance between characters, also it would be inefficient to feed character by character instead of at least word by word.

[deviator]

I agree, I used feed by glyph as an example only.

[p0nce]

https://developer.mozilla.org/en-US/docs/Web/API/TextMetrics

[p0nce]

Depends on #16

[p0nce]

Implemented width aka advance, further work depends on #17

[p0nce]

https://www.cairographics.org/manual/cairo-cairo-scaled-font-t.html#cairo-text-extents-t

[p0nce]

For flow layout we need both horiAdvance and width.

[p0nce]

Fixed, though some values aren't good.