102 lines
3.0 KiB
Kotlin
102 lines
3.0 KiB
Kotlin
// version 1.1.2
|
|
|
|
import java.awt.*
|
|
import javax.swing.*
|
|
|
|
class XiaolinWu: JPanel() {
|
|
init {
|
|
preferredSize = Dimension(640, 640)
|
|
background = Color.white
|
|
}
|
|
|
|
private fun plot(g: Graphics2D, x: Double, y: Double, c: Double) {
|
|
g.color = Color(0f, 0f, 0f, c.toFloat())
|
|
g.fillOval(x.toInt(), y.toInt(), 2, 2)
|
|
}
|
|
|
|
private fun ipart(x: Double) = x.toInt()
|
|
|
|
private fun fpart(x: Double) = x - Math.floor(x)
|
|
|
|
private fun rfpart(x: Double) = 1.0 - fpart(x)
|
|
|
|
private fun drawLine(g: Graphics2D, x0: Double, y0: Double, x1: Double, y1: Double) {
|
|
val steep = Math.abs(y1 - y0) > Math.abs(x1 - x0)
|
|
if (steep) drawLine(g, y0, x0, y1, x1)
|
|
if (x0 > x1) drawLine(g, x1, y1, x0, y0)
|
|
|
|
val dx = x1 - x0
|
|
val dy = y1 - y0
|
|
val gradient = dy / dx
|
|
|
|
// handle first endpoint
|
|
var xend = Math.round(x0).toDouble()
|
|
var yend = y0 + gradient * (xend - x0)
|
|
var xgap = rfpart(x0 + 0.5)
|
|
val xpxl1 = xend // this will be used in the main loop
|
|
val ypxl1 = ipart(yend).toDouble()
|
|
|
|
if (steep) {
|
|
plot(g, ypxl1, xpxl1, rfpart(yend) * xgap)
|
|
plot(g, ypxl1 + 1.0, xpxl1, fpart(yend) * xgap)
|
|
}
|
|
else {
|
|
plot(g, xpxl1, ypxl1, rfpart(yend) * xgap)
|
|
plot(g, xpxl1, ypxl1 + 1.0, fpart(yend) * xgap)
|
|
}
|
|
|
|
// first y-intersection for the main loop
|
|
var intery = yend + gradient
|
|
|
|
// handle second endpoint
|
|
xend = Math.round(x1).toDouble()
|
|
yend = y1 + gradient * (xend - x1)
|
|
xgap = fpart(x1 + 0.5)
|
|
val xpxl2 = xend // this will be used in the main loop
|
|
val ypxl2 = ipart(yend).toDouble()
|
|
|
|
if (steep) {
|
|
plot(g, ypxl2, xpxl2, rfpart(yend) * xgap)
|
|
plot(g, ypxl2 + 1.0, xpxl2, fpart(yend) * xgap)
|
|
}
|
|
else {
|
|
plot(g, xpxl2, ypxl2, rfpart(yend) * xgap)
|
|
plot(g, xpxl2, ypxl2 + 1.0, fpart(yend) * xgap)
|
|
}
|
|
|
|
// main loop
|
|
var x = xpxl1 + 1.0
|
|
while (x <= xpxl2 - 1) {
|
|
if (steep) {
|
|
plot(g, ipart(intery).toDouble(), x, rfpart(intery))
|
|
plot(g, ipart(intery).toDouble() + 1.0, x, fpart(intery))
|
|
}
|
|
else {
|
|
plot(g, x, ipart(intery).toDouble(), rfpart(intery))
|
|
plot(g, x, ipart(intery).toDouble() + 1.0, fpart(intery))
|
|
}
|
|
intery += gradient
|
|
x++
|
|
}
|
|
}
|
|
|
|
override protected fun paintComponent(gg: Graphics) {
|
|
super.paintComponent(gg)
|
|
val g = gg as Graphics2D
|
|
drawLine(g, 550.0, 170.0, 50.0, 435.0)
|
|
}
|
|
}
|
|
|
|
fun main(args: Array<String>) {
|
|
SwingUtilities.invokeLater {
|
|
val f = JFrame()
|
|
f.defaultCloseOperation = JFrame.EXIT_ON_CLOSE
|
|
f.title = "Xiaolin Wu's line algorithm"
|
|
f.isResizable = false
|
|
f.add(XiaolinWu(), BorderLayout.CENTER)
|
|
f.pack()
|
|
f.setLocationRelativeTo(null)
|
|
f.isVisible = true
|
|
}
|
|
}
|