Koch curve

Draw Koch curve. See details: Koch curve

Ring

<lang ring>

1. Project : Koch curve
2. Date  : 2018/04/20
3. Author : Gal Zsolt (~ CalmoSoft ~)
4. Email  : <calmosoft@gmail.com>

load "guilib.ring"

paint = null

new qapp

       {
       win1 = new qwidget() {
                 setwindowtitle("Koch curve")
                 setgeometry(100,100,500,600)
                 label1 = new qlabel(win1) {
                             setgeometry(10,10,400,400)
                             settext("")
                 }
                 new qpushbutton(win1) {
                         setgeometry(150,500,100,30)
                         settext("draw")
                         setclickevent("draw()")
                 }
                 show()
       }
       exec()
       }

func draw

       p1 = new qpicture()
              color = new qcolor() {
              setrgb(0,0,255,255)
       }
       pen = new qpen() {
                setcolor(color)
                setwidth(1)
       }
       paint = new qpainter() {
                 begin(p1)
                 setpen(pen)

       koch(100, 100, 400, 400, 4)

       endpaint()
       }
       label1 { setpicture(p1) show() }

func koch x1, y1, x2, y2, it

       angle = 60*3.14/180
       x3 = (2*x1+x2)/3
       y3 = (2*y1+y2)/3

       x4 = (x1+2*x2)/3
       y4 = (y1+2*y2)/3

       x = x3 + (x4-x3)*cos(angle)+(y4-y3)*sin(angle)
       y = y3 - (x4-x3)*sin(angle)+(y4-y3)*cos(angle)

      if (it > 0)
         koch(x1, y1, x3, y3, it-1)
         koch(x3, y3, x, y, it-1)
         koch(x, y, x4, y4, it-1)
         koch(x4, y4, x2, y2, it-1)
      else
         paint.drawline(x1, y1, x3, y3)
         paint.drawline(x3, y3, x, y)
         paint.drawline(x, y, x4, y4)
         paint.drawline(x4, y4, x2, y2)
     ok

</lang> Output image:

Koch curve