package draw9 import (	"fmt"	"image"	"os") func stringnwidth(f *Font, s string, b []byte, r []rune) int {	const Max = 64	cbuf := make([]uint16, Max)	var in input	in.init(s, b, r)	twid := 0	for !in.done {		max := Max		n := 0		var sf *Subfont		var l, wid int		var subfontname string		for {			if l, wid, subfontname = cachechars(f, &in, cbuf, max); l > 0 {				break			}			if n++; n > 10 {				r := in.ch				name := f.Name				if name == "" {					name = "unnamed font"				}				sf.free()				fmt.Fprintf(os.Stderr, "stringwidth: bad character set for rune %U in %s\n", r, name)				return twid			}			if subfontname != "" {				sf.free()				var err error				sf, err = getsubfont(f.Display, subfontname)				if err != nil {					if f.Display != nil && f != f.Display.DefaultFont {						f = f.Display.DefaultFont						continue					}					break				}				/*				 * must not free sf until cachechars has found it in the cache				 * and picked up its own reference.				 */			}		}		sf.free()		agefont(f)		twid += wid	}	return twid} func (f *Font) StringWidth(s string) int {	f.lock()	defer f.unlock()	return stringnwidth(f, s, nil, nil)} func (f *Font) BytesWidth(b []byte) int {	f.lock()	defer f.unlock()	return stringnwidth(f, "", b, nil)} func (f *Font) RunesWidth(r []rune) int {	f.lock()	defer f.unlock()	return stringnwidth(f, "", nil, r)} func (f *Font) StringSize(s string) image.Point {	return image.Pt(f.StringWidth(s), f.Height)} func (f *Font) BytesSize(b []byte) image.Point {	return image.Pt(f.BytesWidth(b), f.Height)} func (f *Font) RunesSize(r []rune) image.Point {	return image.Pt(f.RunesWidth(r), f.Height)}