Xiaolin Wu's line algorithm: Difference between revisions
Added Kotlin
SqrtNegInf (talk | contribs) m (→{{header|Perl 6}}: parentheses needed around x/y in main loop) |
(Added Kotlin) |
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Line 881:
f.setVisible(true);
});
}
}</lang>
=={{header|Kotlin}}==
{{trans|Java}}
<lang scala>// version 1.1.1
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
}
}</lang>
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