June 2018 Update

Task/Animate-a-pendulum/Ring/animate-a-pendulum.ring

@@ -0,0 +1,82 @@
+# Project : Animate a pendulum
+# Date    : 2018/04/09
+# Author : Gal Zsolt (~ CalmoSoft ~)
+# Email   : <calmosoft@gmail.com>
+
+load "guilib.ring"
+load "stdlib.ring"
+
+CounterMan = 1
+paint = null
+pi = 22/7
+theta = pi/180*40
+g = 9.81
+l = 0.50
+speed = 0
+
+new qapp
+        {
+        win1 = new qwidget() {
+                  setwindowtitle("Animate a pendulum")
+                  setgeometry(100,100,800,600)
+                  label1 = new qlabel(win1) {
+                              setgeometry(10,10,800,600)
+                              settext("")
+                  }
+                  new qpushbutton(win1) {
+                          setgeometry(150,500,100,30)
+                          settext("draw")
+                          setclickevent("draw()")
+                  }
+                  TimerMan = new qtimer(win1)
+                  {
+                                    setinterval(1000)
+                                    settimeoutevent("draw()")
+                                    start()
+                  }
+                  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)
+        ptime()
+        endpaint()
+        }
+        label1 { setpicture(p1) show() }
+        return
+
+ func ptime()
+         TimerMan.start()
+         pPlaySleep()
+         sleep(0.1)
+         CounterMan++
+         if CounterMan = 20
+            TimerMan.stop()
+         ok
+
+func pPlaySleep()
+       pendulum(theta, l)
+       pendulum(theta, l)
+       accel = - g * sin(theta) / l / 100
+       speed = speed + accel / 100
+       theta = theta + speed
+
+func pendulum(a, l)
+       pivotx = 640
+       pivoty = 800
+       bobx = pivotx + l * 1000 * sin(a)
+       boby = pivoty - l * 1000 * cos(a)
+       paint.drawline(pivotx, pivoty, bobx, boby)
+       paint.drawellipse(bobx + 24 * sin(a), boby - 24 * cos(a), 24, 24)