Posted by:
Si Offline a user asked the following questions...
The following problem appears after I hinted a TrueType font for 8p/96dpi: In VTT the text string appears to be ok, all characters are properly spaced.When I install the font I'm currently editing and look at the same text string in Winword 97 the spacing is different.What is the reason for the different behaviour of the same font (I've tested the font under Windows 98 and XP, the same problem)? And, by the way, what is the difference between the two lines of text displayed in the VTT window? It is not mentioned in the manual or in the help file.
And here's Beat's answer...
First part of the question: This is a known issue with Word. In order to support WYSIWYG, Word does its own spacing, which may (and does) override the sidebearings as defined in the font. Word may decide that it needs to move two characters closer together (or further apart) to accomodate rounding differences between the (high-resolution) printer metrics and the (low-resolution) screen metrics. As far as I know, Word doesn't try to guess whether it would be typographically less harmful to drop a pixel here or there. The effect tends to be worst at small type sizes at which a single pixel makes a bigger difference than at large sizes. We hope that with the advent of ClearType this will improve eventually. For the time being, I'd suggest to use Word's View => Web Layout mode, which doesn't do WYSIWYG, for testing your fonts.
Second part of the question: The WYSIWYG problem gets worse if the advance width is hinted, e.g. with a link or a delta. The reason is that for printing, afaik, Word will use the (high-resolution) unhinted (or linear) advance width, and in order to match this on screen, it will have to make more drastic "corrections" than simply even out the rounding differences. I understand that hinting the advance width sometimes is unavoidable, e.g. with a lc "m" (see e.g. Verdana lc "m", 10pt/96 dpi), hence I'm not saying this is wrong. At least, to give people an idea, how much the spacing of a piece of text can differ when it is spaced with linear advance widths, as opposed to hinted advance widths, there are the two lines of sample text. The top one uses linear advance widths, the bottom one the hinted ones. The top approximates what Word would do for WYSIWYG, the bottom one is what I'd expect to see in Word's Web Layout, in Notepad, IE, or Outlook. The more the two lines differ in length, the more spacing problems I'd expect to see in WYSIWYG.
