Re: State of Unicode display support on Windows

[Jason Rumney]

On 12/10/2010 01:33, Óscar Fuentes wrote:
> Some characters display fine on GNU/Linux but not on Windows. An example
> is FISHEYE (?\u25c9) with the Consolas font. Apparently, that font does
> not include that character. In GNU/Linux Emacs simply uses DejaVu for
> displaying the character, but not on Windows, where a white space is
> displayed (the Windows machine also has DejaVu installed.)
>
> Is this a known limitation or a bug?
>
>      
> uniscribe:-outline-Consolas-normal-normal-normal-mono-20-*-*-*-c-*-iso10646-1 
> (#x03)
>    

The font is claiming to have that character in position 3 in the glyph 
table. I've also seen the same thing with fonts claiming position 1.  
There is nothing in the documentation for opentype or the font related 
Windows API functions that suggests that there is anything special about 
those glyph indexes, or that it is safe to assume that they mean a 
character is missing from the font.  Currently I think we only treat a 
return of 0 as indicating that the character is missing, as that is 
reserved by the truetype and opentype specs for the character ".notdef".