Re: [ft] php character map => filter unused characters?

[mpsuzuki]

Hi

On Thu, 03 Nov 2005 13:29:47 +0100
"D.L.D." <address@hidden> wrote:
>is it possible to filter out the rectangle and unused character?

Yes, it's almost possible, although there's no perfect solution.
The rectangle you see is fallbacking glyph. According to Microsoft
TrueType specification (see specification of "loca" table):

>By definition, index zero points to the "missing character,"
>which is the character that appears if a character is not
>found in the font. The missing character is commonly represented
>by a blank box (such as ) or a space.

So, if you exclude the character whose GlyphID=0,
you can exclude the rectangle. But, keep it in your mind:
there are CJK fonts whose GlyphID=0 is a space, and some
CJK fonts uses it for the glyph for "fullwidth space" 
(which is defined charcode) too.

In addition, for multibyte cmap handler of TrueType font
is specified to fallback to GlyphID=0 when the handler
receives undecodable byte sequence (see "cmap" specifcation).
But, I could not find such solid algorithmic specification
for cmap format 0 for ASCII/Latin-1.

>is there a way to do this in php?
>for example filter only the used characters of
>http://www.phpenabled.com/ttf_fontlist/fontlist.php?font=Phones_NormalA.ttf

I'm unfamiliar with PHP - and don't know PHP has FreeType
module or PHP uses independent TTF handler (aslike Fonts-TTF
module of perl).

Regards,
mpsuzuki