Question

How can I draw an elliptic arc with Java without using any standard graphic libraries functions, like Ellipse() or Path()?
The closest idea of what I need to do is Elliptical Arc using Trigonometric Method, but it only shows random arcs, and that is not the way things should go.

The way I’m thinking of is: specify ellipse by two points, then specify angle, which will be cut from this ellipse (or vice versa).
For drawing ellipse I used Bresenham’s algorithm, but it can’t be used for arcs because of mirroring.
Thank you in advance.

Answer 1

You should look from parametric equations. For example, to draw a circle you should first know the circle formula:

x^2 + y^2 = R^2

where R is the radios of the circle.

Now you should write this formula based on the angle (from 1 to 360). Based in a rectangle triangle inside the circle, its trigonometric formula will be:

cos(t)^2 + sin(t)^2 = R^2

where t is the angle, cos(t) will be X and sin(t) will be Y.

So, to draw a circle, you need to pass just the radio of your circle:

public static void drawCircle(int radio, double xCenter, double yCenter) {
    double t = 0;
    double xPoint;
    double yPoint;
    double xActual = xCenter;
    double yActual = yCenter + radio*sin(0);
    t += 0.01;
    while(t < 360) {
        xPoint = xCenter + radio*cos(t);
        yPoint = yCenter + radio*sin(t);
        //you should write this function based on
        //the platform you're working (Swing, AWT...)
        drawLine(xActual, yActual, xPoint, yPoint);
        t += 0.01;
        xActual = xPoint;
        yActual = yPoint;
    }
}

You should review the parametric formulas of the figures you need to draw:

Ellipse