[ft] Type 1 font rendering seems wrong.

[Tim Hutt]

Hi, I'm writing a program that produces PDFs, and depends on exact font 
metrics (it must be able to expand a piece of text to touch the sides of a 
box exactly).

To avoid having to embed fonts in the PDF (a complicated process), I'm using 
one of the base fonts (Helvetica).

Adobe reader actually uses Adobe Sans MM to render the font. I'm pretty sure 
it has the same metrics as Helvetica. The trouble is, freetype seems to load 
it incorrectly. This is especially obvious in the lowercase t.

I've attached an image showing adobe sans mm rendered by freetype, and by 
adobe reader. XPDF produces output similar to adobe readers - I presume it 
uses t1lib for this. Note the different t widths. I'm sure there are other 
difference but they aren't obvious to my eyes.

An additional question: the PDF spec isn't very clear on text sizing, but says 
the 'size' you give it is the distance in points between 'tightly spaced' 
lines of text. Anyone with PDF knowledge know which freetype quantity this 
corresponds to?

Thanks

-Tim

font_comparison.png
Description: PNG image