CODEWITHSUNDEEP
javagraphicsjframegeometryshapes
hazard1994
hazard1994

Reputation: 81

How to draw a circle, positioning it at a double value instead of a int?

Basically, I want to draw a circle using Graphics, but instead of using integers to position it, I would like to use double values instead.

Ideally:

g.drawOval(0.5, 0.5, 50, 50);

Any help is greatly appreciated! Thanks in advance!

Thanks for all the help guys, but ive figured a way out, my dy variable was set at 1, so if i wanted dx to half of that of dy, it would be impossible, instead i just changed dy to 2 and dx to 1! Foolish me!

Upvotes: 3

Views: 12347

Answers (2)

Martijn Courteaux
Martijn Courteaux

Reputation: 68877

The only valid way of doing this is to use an Ellipse2D.Double shape and pass it to the draw(Shape) method of a Graphics2D instance. For the best results, enable anti-aliasing:

public void yourDrawingMethod(Graphics gg)
{
    /* Cast it to Graphics2D */
    Graphics2D g = (Graphics2D) gg;

    /* Enable anti-aliasing and pure stroke */
    g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
    g.setRenderingHint(RenderingHints.KEY_STROKE_CONTROL, RenderingHints.VALUE_STROKE_PURE);

    /* Construct a shape and draw it */
    Ellipse2D.Double shape = new Ellipse2D.Double(0.5, 0.5, 50, 50);
    g.draw(shape);
}

You can use Graphics2D.fill(Shape) as well.

Upvotes: 5

Jakub Zaverka
Jakub Zaverka

Reputation: 8874

If you want continous movement, then the best way is to keep x and y in double variables. As the object moves, the variables will increment at different rates (depending on the angle), and then you can just cast to ints...

And you will get positions:
<0, 0.999> : 0
<1, 1.999> : 1
<2, 2.999> : 2
<3, 3.999> : 3
etc..

For sufficiently long movement it will seem fluent. But the positions must be integer values, because you are bound by technology. You cannot display something at 0.3 pixels. You either have the pixel or not, you cannot have only 0.3 of it.

Upvotes: -1

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