Circle with ticks: Difference between revisions

Revision as of 22:03, 24 March 2014

@@ Line 6: / Line 6: @@
 var circ = brd.create('circle', [p, q]);
+// Create an empty curve
 var ticks = brd.create('curve', [[0], [0]],
               {strokeWidth: 1,
                strokeColor: 'blue',
                strokeOpacity: 0.5});
+// Make ticks out of the curve
 ticks.updateDataArray = function() {
      var cx = circ.center.X(),
@@ Line 15: / Line 18: @@
          r = circ.Radius(),
          i,
-         ticklen = 0.3,
+         ticklen = 0.3,           // Length of ticks in user space coordinates
-         steps = 20,
+         steps = 20,              // Number of ticks
          d = ticklen * 0.5,
          alpha = 2 * Math.PI / steps;
@@ Line 23: / Line 26: @@
      this.dataY = [];
      for (i = 0; i < steps; i++) {
+        // Start of a tick
          this.dataX.push( cx + (r - d)* Math.cos(i * alpha) );
          this.dataY.push( cy + (r - d) * Math.sin(i * alpha) );
+        // End of tick
          this.dataX.push( cx + (r + d) * Math.cos(i * alpha) );
          this.dataY.push( cy + (r + d) * Math.sin(i * alpha) );
+        // Interrupt the curve
          this.dataX.push( NaN );
          this.dataY.push( NaN );