Textfields created and stored in Animate/Flash swf assets do not use any change to letterSpacing value. If it is set in the swf, the letterSpacing value of the defaultTextFormat is 0. Changing it through code changes the letterSpacing value but still has no visual effect. And yes, I did reassign the defaultTextFormat and the text to the field after changing letterSpacing.
Possibly related: even in pure Flash/As3, Swf Fields with letter spacing less than 0 will have a letter spacing of 0 once the value of that field changes. Is this happening to you with values higher than 0 or just lower? this may be an issue with Animate, only
I’m using letter spacing greater than 0. The textfields I’m talking about worked fine in the Animate/Flash projects I’m converting to HTML5 using OpenFL.
It’s possible we don’t properly export letterSpacing in our SWF converter, though letterSpacing has not been fully supported in OpenFL TextField, but I think recently some support was added. What happens if you add it to a TextField yourself? Thanks 
Has support for TextFormat.letterSpacing been added yet to OpenFL?
If not, why not?
I think it’s a limitation of fillText, it doesn’t support multiple characters and has spacing. If a single character is drawn with fillText, it will consume a lot of performance.
I think I can cache the text and use it as a sprite sheet.