How to calculate letterSpacing for TextView from sketch values?

Question

In design I have a text field with 16 as text size and 0.6 as character spacing

But, if I set this value for android:letterSpacing attribute of TextView spacing will be much more larger than in design.

So, what is the way to convert sketch value to android value?

Answer 1

According to Romain Guy, Android uses the "1 em = font size" definition, so you'd just do

setLetterSpacing(characterSpacing / textSize)

...just make sure those values are in the same unit (dp vs px)

Answer 2

If Sketch provides the letter spacing value in Points, then the following is the conversion:

float textSizePx = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,  textSizeInSp, displayMetrics);
float letterSpacingPx = TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_PT,  sketchLetterSpacing, displayMetrics); 
float androidLetterSpacing = letterSpacingPx / textSizePx
return androidLetterSpacing;