io.data2viz.shape.link.Link.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.link
import io.data2viz.geom.Path
import io.data2viz.shape.const
/**
* Instanciate and configure an horizontal link builder
*/
fun linkBuilderH(init: LinkBuilder.() -> Unit) = LinkBuilder().apply {
curve = this::curveHorizontal
init()
}
/**
* Instanciates and configure a vertical link builder.
*/
fun linkBuilderV(init: LinkBuilder.() -> Unit) = LinkBuilder().apply {
curve = this::curveVertical
init()
}
/**
* The link shape generates a smooth cubic Bézier curve from a source point to a target point.
* The tangents of the curve at the start and end are either vertical, horizontal or radial.
*/
class LinkBuilder {
var x0: (D) -> Double = const(.0)
var x1: (D) -> Double = const(.0)
var y0: (D) -> Double = const(.0)
var y1: (D) -> Double = const(.0)
var curve: (Path, Double, Double, Double, Double) -> Unit = ::curveHorizontal
fun link(data:D, path:C) {
curve(path, x0(data), y0(data), x1(data), y1(data))
}
internal fun curveHorizontal(path:C, x0:Double, y0:Double, x1:Double, y1:Double) {
path.moveTo(x0, y0)
val newX0 = (x0 + x1) / 2
path.bezierCurveTo(newX0, y0, newX0, y1, x1, y1)
}
internal fun curveVertical(path:C, x0:Double, y0:Double, x1:Double, y1:Double) {
path.moveTo(x0, y0)
val newY0 = (y0 + y1) / 2
path.bezierCurveTo(x0, newY0, x1, newY0, x1, y1)
}
}