Sierpinski pentagon: Difference between revisions
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(dc-draw-pentagon 5 640 640)</lang>
=={{header|Scala}}==
===Java Swing Interoperability===
<lang Scala>import java.awt._
import java.awt.event.ActionEvent
import java.awt.geom.Path2D
import javax.swing._
import scala.annotation.tailrec
import scala.math.{Pi, cos, sin, sqrt}
object SierpinskiPentagon extends App {
SwingUtilities.invokeLater(() => {
class SierpinskiPentagon extends JPanel {
/* Try to avoid random color values clumping together */
private var hue = math.random
// exterior angle
private val deg072 = 2 * Pi / 5d //toRadians(72)
/* After scaling we'll have 2 sides plus a gap occupying the length
of a side before scaling. The gap is the base of an isosceles triangle
with a base angle of 72 degrees. */
//private val scaleFactor = 1 / (2 + cos(deg072) * 2)
private var limit = 0
private def drawPentagon(g: Graphics2D, x: Double, y: Double, side: Double, depth: Int): Unit = {
val scaleFactor = 1 / (2 + cos(deg072) * 2)
if (depth == 0) {
// draw from the top
@tailrec
def iter0(i: Int, x: Double, y: Double, angle: Double, p: Path2D.Double): Path2D.Double = {
if (i < 0) p
else {
p.lineTo(x, y)
iter0(i - 1, x + cos(angle) * side, y - sin(angle) * side, angle + deg072, p)
}
}
def p1: Path2D.Double = iter0(4, x, y, 3 * deg072, {
val p = new Path2D.Double
p.moveTo(x, y)
p
})
def p: Path2D.Double = iter0(4, x, y, 3 * deg072, p1)
def next: Color = {
hue = (hue + (sqrt(5) - 1) / 2) % 1
Color.getHSBColor(hue.toFloat, 1, 1)
}
g.setColor(next)
g.fill(p)
}
else {
val _side = side * scaleFactor
/* Starting at the top of the highest pentagon, calculate
the top vertices of the other pentagons by taking the
length of the scaled side plus the length of the gap. */
val distance = _side + _side * cos(deg072) * 2
/* The top positions form a virtual pentagon of their own,
so simply move from one to the other by changing direction. */
def iter1(i: Int, x: Double, y: Double, angle: Double): Unit = {
if (i < 0) ()
else {
drawPentagon(g, x, y, _side, depth - 1)
iter1(i - 1, x + cos(angle) * distance, y - sin(angle) * distance, angle + deg072)
}
}
iter1(4, x + cos(3 * deg072) * distance, y - sin(3 * deg072) * distance, 4 * deg072)
}
}
override def paintComponent(gg: Graphics): Unit = {
val (g, margin) = (gg.asInstanceOf[Graphics2D], 20)
val side = (getWidth / 2 - 2 * margin) * sin(Pi / 5) * 2
super.paintComponent(gg)
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON)
drawPentagon(g, getWidth / 2, 3 * margin, side, limit)
}
new Timer(3000, (_: ActionEvent) => {
limit += 1
if (limit >= 5) limit = 0
repaint()
}).start()
setPreferredSize(new Dimension(640, 640))
setBackground(Color.white)
}
val f = new JFrame("Sierpinski Pentagon") {
setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE)
setResizable(true)
add(new SierpinskiPentagon, BorderLayout.CENTER)
pack()
setLocationRelativeTo(null)
setVisible(true)
}
})
}</lang>
=={{header|Sidef}}==
{{trans|Perl 6}}
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