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vector: Reduce necessary vertices

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This commit is contained in:
Hajime Hoshi 2019-12-29 01:47:18 +09:00
parent cee11bd822
commit 08be478dfc
1 changed files with 23 additions and 10 deletions
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33
vector/path.go
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@ -54,13 +54,30 @@ func (p *Path) LineTo(x, y float32) {
p.cur = math.Point{X: x, Y: y}
}
func (p *Path) QuadraticCurveTo(cpx, cpy, x, y float32) {
c := p.cur
dist := float64((x-c.X)*(x-c.X) + (y-c.Y)*(y-c.Y))
num := 1.0
for num*num < dist {
func nseg(x0, y0, x1, y1 float32) int {
distx := x1 - x0
if distx < 0 {
distx = -distx
}
disty := y1 - y0
if disty < 0 {
disty = -disty
}
dist := distx
if dist < disty {
dist = disty
}
num := 1
for float32(num) < dist {
num *= 2
}
return num
}
func (p *Path) QuadraticCurveTo(cpx, cpy, x, y float32) {
c := p.cur
num := nseg(c.X, c.Y, x, y)
for t := float32(0.0); t <= 1; t += 1.0 / float32(num) {
xf := (1-t)*(1-t)*c.X + 2*t*(1-t)*cpx + t*t*x
yf := (1-t)*(1-t)*c.Y + 2*t*(1-t)*cpy + t*t*y
@ -70,11 +87,7 @@ func (p *Path) QuadraticCurveTo(cpx, cpy, x, y float32) {
func (p *Path) BezierCurveTo(cp0x, cp0y, cp1x, cp1y, x, y float32) {
c := p.cur
dist := float64((x-c.X)*(x-c.X) + (y-c.Y)*(y-c.Y))
num := 1.0
for num*num < dist {
num *= 2
}
num := nseg(c.X, c.Y, x, y)
for t := float32(0.0); t <= 1; t += 1.0 / float32(num) {
xf := (1-t)*(1-t)*(1-t)*c.X + 3*(1-t)*(1-t)*t*cp0x + 3*(1-t)*t*t*cp1x + t*t*t*x
yf := (1-t)*(1-t)*(1-t)*c.Y + 3*(1-t)*(1-t)*t*cp0y + 3*(1-t)*t*t*cp1y + t*t*t*y