Windows vertical metrics calculations

#1

I appreciate svg bitmap fonts are not yet supported by windows office. But it would be good to future proof fonts exported now in Fontself for office users if Microsoft ever get round to supporting svg in the future.

In this respect I think the WinAscent and WinDescent values that Fontself is currently exporting are probably quite low. (I assume they are currently being calculated by the upper and lowest height of the image files?). Wouldn’t it be safer to use typoAscender and typoDescender values? Or alternatively is there a way I can set my own values in Fontself instead of them being automatic?

54

Thanks

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#2

The WinAscent value is defined in the specifications as the most extreme point, and anything above might be cropped: https://docs.microsoft.com/en-us/typography/opentype/spec/os2#uswinascent

This value cannot be edited for now within Fontself.

#3

Yeah its just that its quite unusual for the winAscent/WinDecent to be a much smaller value than the typo/hhea Descender/Ascender values… And as ‘Some legacy applications use the usWinAscent and usWinDescent values to determine default line spacing’ I just thought it could be a better strategy to use the user defined vertical metrics instead?

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