io.data2viz.shape.AreaBuilder.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
import io.data2viz.geom.Path
fun areaBuilder(init: AreaBuilder.() -> Unit) = AreaBuilder().apply(init)
/**
* The area generator produces an area, as in an area chart. An area is defined by two bounding lines, either splines
* or polylines. Typically, the two lines share the same x-values (x0 = x1), differing only in y-value (y0 and y1);
* most commonly, y0 is defined as a constant representing zero. The first line (the topline) is defined by x1 and y1
* and is rendered first; the second line (the baseline) is defined by x0 and y0 and is rendered second, with the
* points in reverse order. With a curveLinear curve, this produces a clockwise polygon.
*/
class AreaBuilder {
/**
* The type of curve used to draw the bounding lines of the area.
*/
var curve: (Path) -> Curve = curves.linear
/**
* X-value for the base-line, should take a Domain object and return a Double.
*/
var xBaseline: (D) -> Double = const(.0)
/**
* Y-value for the base-line, should take a Domain object and return a Double.
*/
var yBaseline: (D) -> Double = const(.0)
/**
* X-value for the top-line, should take a Domain object and return a Double.
* If xTopline is the same as xBaseline you may let it null.
*/
var xTopline: ((D) -> Double)? = null
/**
* Y-value for the top-line, should take a Domain object and return a Double.
* If yTopline is the same as yBaseline you may let it null.
*/
var yTopline: ((D) -> Double)? = null
/**
* This will indicate if a Domain value should be displayed.
* If defined(d) returns true, the point is on the line.
* If defined(d) returns false, the point is omitted.
*/
var defined: (D) -> Boolean = const(true)
// TODO : implements ?
/*fun arealine() {
return line().defined(defined).curve(curve).path(path);
}
fun lineX0() { return lineY0()}
fun lineY0() {
return arealine().x(x0).y(y0)
}
fun lineY1() {
return arealine().x(x0).y(y1)
}
fun lineX1() {
return arealine().x(x1).y(y0)
}*/
/**
* Use the data to generate an area on the path
*/
fun render(data: List, path: C): C {
val n = data.size
val x0z = Array(n, { 0.0 })
val y0z = Array(n, { 0.0 })
var j = 0
var defined0 = false
val output = curve(path)
for (i in 0..n) {
val areaNotEnded = i < n
val undefined = !(areaNotEnded && defined(data[i]))
if (undefined == defined0) {
defined0 = !defined0
if (defined0) {
j = i
output.areaStart()
output.lineStart()
} else {
output.lineEnd()
output.lineStart()
for (k in i - 1 downTo j) {
output.point(x0z[k], y0z[k])
}
output.lineEnd()
output.areaEnd()
}
}
if (defined0) {
val d = data[i]
x0z[i] = xBaseline(d)
y0z[i] = yBaseline(d)
val outputX = if (xTopline != null) xTopline!!(d) else x0z[i]
val outputY = if (yTopline != null) yTopline!!(d) else y0z[i]
output.point(outputX, outputY)
}
}
return path
}
}