io.data2viz.shape.curve.CatmullRom.kt Maven / Gradle / Ivy
package io.data2viz.shape.curve
import io.data2viz.geom.Path
import io.data2viz.shape.Curve
import io.data2viz.shape.epsilon
import kotlin.math.pow
import kotlin.math.sqrt
class CatmullRom(override val path: Path, val alpha: Double = 0.5) : Curve {
private var x0 = -1.0
private var y0 = -1.0
private var x1 = -1.0
private var y1 = -1.0
private var x2 = -1.0
private var y2 = -1.0
private var _l01_a = 0.0
private var _l12_a = 0.0
private var _l23_a = 0.0
private var _l01_2a = 0.0
private var _l12_2a = 0.0
private var _l23_2a = 0.0
private var lineStatus = -1
private var pointStatus = -1
override fun areaStart() {
lineStatus = 0
}
override fun areaEnd() {
lineStatus = -1
}
override fun lineStart() {
x0 = -1.0
y0 = -1.0
x1 = -1.0
y1 = -1.0
x2 = -1.0
y2 = -1.0
_l01_a = 0.0
_l12_a = 0.0
_l23_a = 0.0
_l01_2a = 0.0
_l12_2a = 0.0
_l23_2a = 0.0
pointStatus = 0
}
override fun lineEnd() {
when (pointStatus) {
2 -> path.lineTo(x2, y2)
3 -> point(x2, y2)
}
if (lineStatus > -1) {
if (lineStatus > 0) {
path.closePath()
}
lineStatus = 1 - lineStatus
}
}
private fun curve(x: Double, y: Double) {
var _x1 = x1
var _y1 = y1
var _x2 = x2
var _y2 = y2
if (_l01_a > epsilon) {
val a = 2 * _l01_2a + 3 * _l01_a * _l12_a + _l12_2a
val n = 3 * _l01_a * (_l01_a + _l12_a)
_x1 = (x1 * a - x0 * _l12_2a + x2 * _l01_2a) / n
_y1 = (y1 * a - y0 * _l12_2a + y2 * _l01_2a) / n
}
if (_l23_a > epsilon) {
val b = 2 * _l23_2a + 3 * _l23_a * _l12_a + _l12_2a
val m = 3 * _l23_a * (_l23_a + _l12_a)
_x2 = (x2 * b + x1 * _l23_2a - x * _l12_2a) / m
_y2 = (y2 * b + y1 * _l23_2a - y * _l12_2a) / m
}
path.bezierCurveTo(_x1, _y1, _x2, _y2, x2, y2)
}
override fun point(x: Double, y: Double) {
if (pointStatus > 0) {
val x23 = x2 - x
val y23 = y2 - y
_l23_2a = (x23 * x23 + y23 * y23).pow(alpha)
_l23_a = sqrt(_l23_2a)
}
when (pointStatus) {
0 -> {
pointStatus = 1
if (lineStatus > 0) path.lineTo(x, y) else path.moveTo(x, y)
}
1 -> pointStatus = 2
2 -> {
pointStatus = 3
curve(x, y)
}
else -> curve(x, y)
}
_l01_a = _l12_a
_l12_a = _l23_a
_l01_2a = _l12_2a
_l12_2a = _l23_2a
x0 = x1
x1 = x2
x2 = x
y0 = y1
y1 = y2
y2 = y
}
}