Draw transparent circle filled outside

Question

I have a mapview that I want to draw a circle on to focus on a given area. But i want the circle to be inverted. That is, instead of the inside of the circle being filled, i

Answer 1

You can create a new BufferedImage, fill it grey then erase the circle where you want.

And then, draw that BufferedImage on top of your view.

BufferedImage img = new BufferedImage(sizeX, sizeY, BufferedImage.TYPE_INT_RGBA);
Graphics2D g = img.createGraphics();

int ovalX = 50;
int ovalY = 70;
int ovalRadius = 20;

/* Draw the grey rectangle */
g.setColor(Color.GRAY);
g.fillRect(0, 0, sizeX, sizeY);

/* Enable Anti-Alias */
g.setRenderingHint(RenderingHints.HINT_ANTIALIAS, RenderingHints.VALUE_ANTIALIAS_ON);

/* Clear the circle away */
g.setComposite(AlphaComposite.CLEAR, 1.0f);
g.fillOval(ovalX - ovalRadius, ovalY - ovalRadius, 2 * ovalRadius, 2 * ovalRadius);

g.dispose();