Exemplo n.º 1
0
// 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
}
Exemplo n.º 2
0
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
}