*Frustrated* :(

[Mark321]

I've noticed something interesting that puzzles me to no end...

How come, when I go to websites that showcase fonts for sale or free, and they display the fonts as a demonstration of how they look....yet... when I try to use that very same font, I get lack luster results. I tighten up the tracking on each individual letter (or loosen it if needs be) but when I use the same fonts I don't get the results they demo.
My text doesn't look as awesome as theirs. Why?
I'm still trying to figure this one out.....what am I missing that they know and I don't? It's still the exact same font! I can't be crazy. I know they are doing something....but what???

*Frustrated*

[mwenz]

Dear Frustrated...

XDP 12 (365) is the first version that supports GPOS tables if I recall. If I were to do a comparison, I don't think I would opt to compare to the font author's image tiles displaying their font. I would compare to known applications that have long supported GPOS tables, like InDesign, QuarkXPress, etc., to XDP 12. If I found they were off in glyph positioning (GPOS), then I would file a support ticket.

So how about a few font names? If I have them I would be happy to see if the results are different between applications.

Mike

[Mark321]

Mike,

I don't know about GPOS. I'm new to the concept. Please tell me more about it. I'm using Xara Designer Pro v.12.

Mark

[mwenz]

Fonts contain kerning tables. There are two kinds of kerning tables. TrueType contain only one type of kerning tables and Xara products likely was always able to use these kerning tables. OpenType fonts that contain TrueType curves may have two types of kerning tables, both a kern table and a GPOS table. GPOS stands for Gyph POSitioning. Xara products before XDP 365 could not use the GPOS tables, but if those kinds of OpenType fonts contained both kinds of kerning tables, XDP could make use of the old TrueType kern table.

However, OpenType fonts that use PostScript curves to draw the glyphs inside the font can only have GPOS kerning tables. Which means that Xara applications before XDP 365 could not ever use the kerning from inside the font. Which was bad.

Information that will make your eyes bleed follows...

The glyphs (what we know of as characters) have what are called left and right side bearings. These Left/Right Bearings are illustrated below with the A glyph.



For this font there is 25 funits (font units) on the left of the A and 75 funits on the right side. As all glyphs have L/R bearings, there is a natural amount of space between letters. Depending upon how the font is designed, many/most characters can have little to no kerning--an instruction that forces two letters closer or further apart--but certain characters will generally require kerning by the font author to bring certain letter pairs closer or further apart.

Kerning tables are based upon letter pairs--two consecutive letters. So if I were to add the letter V with the A and not use kerning, I would see the following:



Notice the red line I drew. The right side bearing for the A is about where the red line is. The left side bearing of the V is also about where the red line is. Because I internally kerned this letter pair, if I turn the kerning feature on, then the V is pulled closer to the A like below:



Notice the left side of the V is now overhanging the lower right side of the A. That is the kerning that happens inside the font done by the font author. Now, you or I may or may not like the amount of kerning for these two letters. Perhaps you want this pair closer together, Bob wants it further apart. That is where application-based kerning comes in. Applications that can allow the user to adjust the kerning overrides the kerning the font author has done inside the font.

I have fonts that have zero kerning. And some of those fonts work well as designed. But most fonts will contain kern tables of one kind or another (or both) and we may not like the amount of kerning. The goal as a font author is, for me, to minimize the amount of kerning inside the font for the body of the font. Special pairs, like the AV, AW, etc., will nearly always need to be in the font. But for specific uses--like those image tiles on the font web sites--may require more or less kerning to achieve the desired design result.

OK. Now about the fonts that cause you frustration. I can bet that if you copied one of the image tiles that look good on-screen and import it into XDP, then type out the same phrase and place it on top of the image, you can match what they created. But perhaps you can also improve upon it.

Mike

[Mark321]

Simply amazing Mike.

You are so helpful!

Thanks
Mark

[roly]

Mike that was an excellent explanation ( using text and pictures) of a topic that I have always been curious about but would never dare to touch. Thanks again.

Ciao

Roly