Re: ELPA: New package: svg-lib

[Nicolas P. Rougier (inria)]

Alan Third <alan@idiocy.org> writes:

> FWIW, I believe that librsvg defaults to 96dpi, however I'm not 
> sure
> that it always did, I've a feeling it used to use something 
> different,
> so different versions of librsvg may use different default 
> DPIs. Only
> Emacs 28 explicitly sets a DPI, so Emacs 27 will use whatever is
> default for librsvg.

If librsvg changed its default DPI, that would explain why some 
users get a wrong result depending on their lib version.

> I ended up using pixels for font sizes rather than trying to get 
> point
> sizes to match up. When I DID try to use point sizes, on macOS I 
> had
> to multiply every size by something like 72/96. That calculation 
> would
> vary with OS and GUI toolkit, and possibly monitor size too.

I went down this road too and remember having tested the 72/96 
ratio without much success.
More specifically, I try to compute the actual screen dpi and 
adapt the font size but it did not work so well.

Nicolas