Use fewer ops to calculate mid-point

This commit is contained in:
Dan Kortschak 2019-02-20 17:08:29 +10:30
parent 9db508d34a
commit f23d82b106

View File

@ -585,8 +585,8 @@ func (dc *Context) DrawEllipticalArc(x, y, rx, ry, angle1, angle2 float64) {
a2 := angle1 + (angle2-angle1)*p2 a2 := angle1 + (angle2-angle1)*p2
x0 := x + rx*math.Cos(a1) x0 := x + rx*math.Cos(a1)
y0 := y + ry*math.Sin(a1) y0 := y + ry*math.Sin(a1)
x1 := x + rx*math.Cos(a1+(a2-a1)/2) x1 := x + rx*math.Cos((a1+a2)/2)
y1 := y + ry*math.Sin(a1+(a2-a1)/2) y1 := y + ry*math.Sin((a1+a2)/2)
x2 := x + rx*math.Cos(a2) x2 := x + rx*math.Cos(a2)
y2 := y + ry*math.Sin(a2) y2 := y + ry*math.Sin(a2)
cx := 2*x1 - x0/2 - x2/2 cx := 2*x1 - x0/2 - x2/2