Re: Google's NotoColorEmoji-Regular.ttf not rending

[Werner LEMBERG]

> Thanks, ftview is a great help. However it does not display
> NotoColorEmoji-Regular.ttf

Well, this font contains a 'COLR' v1 table, which `ftview` doesn't
support – you have to render the layers by yourself.[*] Note that
'COLR' v1 support in FreeType is not complete yet (but Dominik is
working on it).

It also contains an 'SVG' table, and this gets displayed with the
current git version of FreeType, assuming that you are linking to
'librsvg'.

However, there is a problem somewhere, since a simple

```
ftview 100 NotoColorEmoji-Regular.ttf 
```

takes 24s to display the first few glyphs, which is unacceptably slow.
This is with my system's librsvg version 2.52.6.

Using `kcachegrind` to look at the output from

```
valgrind --tool=callgrind ftview -k q -f 5 400 NotoColorEmoji-Regular.ttf 
```

(from a `make devel` build, which includes the FreeType library
statically) to display the glyph with index 5 at a resolution of 400px
(attached), it seems that most time gets used in 'librsvg' (51%) and
'libcairo' (30%).

Moazin, please have a look!


    Werner


[*] That FreeType supports rendering of 'COLR' v0 is just a
    convenience and not recommended for all use cases.

ftview.callgrind.out.xz
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