[ft] Glyph rendered with different bitmap width

[Sherwood Hu]

I noticed a problem when I render a true type font.

 

All gyphs in the font have a fixed width of 550 font units. Its EM size is 1024. So at 29.5 points and 600 dpi, all glyphs should have a width of 132 dots, according to:

 

29.5*550/(72*1024) = 0.22 (inch) * 600 = 132.

 

Unfortunately I got different results from 98 dots to 132 dots –quite a wide range.

 

What may cause the problem? The width is quite important for the results. Is there any way I can work around the issue?

 

Thanks!