// DrawString draws s at p and returns p advanced by the text extent. The text
// is placed so that the left edge of the em square of the first character of s
// and the baseline intersect at p. The majority of the affected pixels will be
// above and to the right of the point, but some may be below or to the left.
// For example, drawing a string that starts with a 'J' in an italic font may
// affect pixels below and left of the point.
//
// p is a fixed.Point26_6 and can therefore represent sub-pixel positions.
func (c *Context) DrawString(s string, p fixed.Point26_6) (fixed.Point26_6, error) {
if c.f == nil {
return fixed.Point26_6{}, errors.New("freetype: DrawText called with a nil font")
}
prev, hasPrev := truetype.Index(0), false
for _, rune := range s {
index := c.f.Index(rune)
if hasPrev {
kern := c.f.Kern(c.scale, prev, index)
if c.hinting != font.HintingNone {
kern = (kern + 32) &^ 63
}
p.X += kern
}
advanceWidth, mask, offset, err := c.glyph(index, p)
if err != nil {
return fixed.Point26_6{}, err
}
p.X += advanceWidth
glyphRect := mask.Bounds().Add(offset)
dr := c.clip.Intersect(glyphRect)
if !dr.Empty() {
mp := image.Point{0, dr.Min.Y - glyphRect.Min.Y}
draw.DrawMask(c.dst, dr, c.src, image.ZP, mask, mp, draw.Over)
}
prev, hasPrev = index, true
}
return p, nil
}
func (self rightToLeft) Advance(face font.Face, origin fixed.Point26_6, dot fixed.Point26_6, prev rune, char rune) (begin fixed.Point26_6, end fixed.Point26_6) {
if char == '\n' {
dot.X = origin.X
dot.Y += face.Metrics().Height
return dot, dot
}
if prev != 0 {
dot.X -= face.Kern(prev, char)
}
dot.X -= advance(face, char)
return dot, dot
}