Esempio n. 1
0
// GetStringBounds returns the approximate pixel bounds of the string s at x, y.
// The the left edge of the em square of the first character of s
// and the baseline intersect at 0, 0 in the returned coordinates.
// Therefore the top and left coordinates may well be negative.
func (gc *GraphicContext) GetStringBounds(s string) (left, top, right, bottom float64) {
	font, err := gc.loadCurrentFont()
	if err != nil {
		log.Println(err)
		return 0, 0, 0, 0
	}
	top, left, bottom, right = 10e6, 10e6, -10e6, -10e6
	cursor := 0.0
	prev, hasPrev := truetype.Index(0), false
	for _, rune := range s {
		index := font.Index(rune)
		if hasPrev {

			cursor += fUnitsToFloat64(font.Kerning(int32(gc.Current.Scale), prev, index))
		}
		if err := gc.glyphBuf.Load(gc.Current.Font, int32(gc.Current.Scale), index, truetype.NoHinting); err != nil {
			log.Println(err)
			return 0, 0, 0, 0
		}
		e0 := 0
		for _, e1 := range gc.glyphBuf.End {
			ps := gc.glyphBuf.Point[e0:e1]
			for _, p := range ps {
				x, y := pointToF64Point(p)
				top = math.Min(top, y)
				bottom = math.Max(bottom, y)
				left = math.Min(left, x+cursor)
				right = math.Max(right, x+cursor)
			}
		}
		cursor += fUnitsToFloat64(font.HMetric(int32(gc.Current.Scale), index).AdvanceWidth)
		prev, hasPrev = index, true
	}
	return left, top, right, bottom
}
Esempio n. 2
0
// CreateStringPath creates a path from the string s at x, y, and returns the string width.
// The text is placed so that the left edge of the em square of the first character of s
// and the baseline intersect at x, y. 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.
func (gc *GraphicContext) CreateStringPath(s string, x, y float64) float64 {
	font, err := gc.loadCurrentFont()
	if err != nil {
		log.Println(err)
		return 0.0
	}
	startx := x
	prev, hasPrev := truetype.Index(0), false
	for _, rune := range s {
		index := font.Index(rune)
		if hasPrev {
			x += fUnitsToFloat64(font.Kerning(int32(gc.Current.Scale), prev, index))
		}
		err := gc.drawGlyph(index, x, y)
		if err != nil {
			log.Println(err)
			return startx - x
		}
		x += fUnitsToFloat64(font.HMetric(int32(gc.Current.Scale), index).AdvanceWidth)
		prev, hasPrev = index, true
	}
	return x - startx
}