freetype-go: change freetype.DrawText's point to be at the baseline

instead of at 1em above the baseline.

R=r
CC=golang-dev
http://codereview.appspot.com/2042041
This commit is contained in:
Nigel Tao 2010-08-27 15:49:35 +10:00
parent 29c473cb3e
commit b8ed0a9c12
2 changed files with 10 additions and 10 deletions

View File

@ -104,7 +104,7 @@ func main() {
}
// Draw the text.
pt := freetype.Pt(10, 10)
pt := freetype.Pt(10, 10+c.FUnitToPixelRU(font.UnitsPerEm()))
for _, s := range text {
err = c.DrawText(gcp, pt, s)
if err != nil {

View File

@ -87,14 +87,14 @@ func (c *Context) drawContour(ps []truetype.Point, dx, dy raster.Fix32) {
// going downwards, and offset by (dx, dy)
start := raster.Point{
dx + c.FUnitToFix32(int(ps[0].X)),
dy + c.FUnitToFix32(c.upe-int(ps[0].Y)),
dy + c.FUnitToFix32(-int(ps[0].Y)),
}
c.r.Start(start)
q0, on0 := start, true
for _, p := range ps[1:] {
q := raster.Point{
dx + c.FUnitToFix32(int(p.X)),
dy + c.FUnitToFix32(c.upe-int(p.Y)),
dy + c.FUnitToFix32(-int(p.Y)),
}
on := p.Flags&0x01 != 0
if on {
@ -124,11 +124,11 @@ func (c *Context) drawContour(ps []truetype.Point, dx, dy raster.Fix32) {
}
}
// DrawText draws s at pt using p. The text is placed so that the top left of
// the em square of the first character of s is equal to pt. The majority of
// the affected pixels will be below and to the right of pt, but some may be
// above or to the left. For example, drawing a string that starts with a 'J'
// in an italic font may affect pixels to the left of pt.
// DrawText draws s at pt using p. The text is placed so that the left edge of
// the em square of the first character of s and the baseline intersect at pt.
// The majority of the affected pixels will be above and to the right of pt,
// 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 pt.
// pt is a raster.Point and can therefore represent sub-pixel positions.
func (c *Context) DrawText(p raster.Painter, pt raster.Point, s string) (err os.Error) {
if c.font == nil {
@ -192,9 +192,9 @@ func (c *Context) recalc() {
} else {
b := c.font.Bounds()
c.xmin = c.FUnitToPixelRD(int(b.XMin))
c.ymin = c.FUnitToPixelRD(c.upe - int(b.YMax))
c.ymin = c.FUnitToPixelRD(-int(b.YMax))
xmax := c.FUnitToPixelRU(int(b.XMax))
ymax := c.FUnitToPixelRU(c.upe - int(b.YMin))
ymax := c.FUnitToPixelRU(-int(b.YMin))
c.r.SetBounds(xmax-c.xmin, ymax-c.ymin)
}
}