io.data2viz.shape.curve.CardinalOpen.kt Maven / Gradle / Ivy
/*
* Copyright (c) 2018-2019. data2viz sàrl.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*
*/
package io.data2viz.shape.curve
import io.data2viz.geom.Path
import io.data2viz.shape.Curve
class CardinalOpen(override val path: Path, tension: Double = 0.0) : 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 lineStatus = -1
private var pointStatus = -1
private val k = (1.0 - tension) / 6.0
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
pointStatus = 0
}
override fun lineEnd() {
if (lineStatus > -1) {
if (lineStatus > 0) {
path.closePath()
}
lineStatus = 1 - lineStatus
}
}
// TODO : non specific, inherit from Cardinal
private fun curve(x: Double, y: Double) {
path.bezierCurveTo(
x1 + k * (x2 - x0),
y1 + k * (y2 - y0),
x2 + k * (x1 - x),
y2 + k * (y1 - y),
x2,
y2
)
}
override fun point(x: Double, y: Double) {
when (pointStatus) {
0 -> pointStatus = 1
1 -> pointStatus = 2
2 -> {
pointStatus = 3
if (lineStatus > 0) path.lineTo(x2, y2) else path.moveTo(x2, y2)
}
3 -> {
pointStatus = 4
curve(x, y)
}
else -> curve(x, y)
}
x0 = x1
x1 = x2
x2 = x
y0 = y1
y1 = y2
y2 = y
}
}