Add ticks to the circle line. The ticks are realized as a single curve. It is divided into short segments by adding `NaN`s.
// Define the id of your board in BOARDID
const board = JXG.JSXGraph.initBoard(BOARDID, {
axis: false,
boundingbox: [-5, 5, 5, -5],
keepaspectratio: true
});
// Circle through q with center p.
var p = board.create('point', [0, 0]);
var q = board.create('point', [3, 3]);
var circ = board.create('circle', [p, q]);
// Create an empty curve
var ticks = board.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(),
cy = circ.center.Y(),
r = circ.Radius(),
i,
ticklen = 0.3, // Length of ticks in user space coordinates
steps = 20, // Number of ticks
d = ticklen * 0.5,
alpha = 2 * Math.PI / steps; // Angle between ticks
this.dataX = [];
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);
}
};
board.update();
This example is licensed under a Creative Commons Attribution 4.0 International License.
Please note that you have to mention The Center of Mobile Learning with Digital Technology in the credits.