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javagraphics2dimaging

Filling A Circle On The Outside, Inside Becomes Transparent

Alright Stackoverflow, I need your help on this one with drawing.

I am restricted to Graphics2D for this one and was wondering how I would be able to achieve an image that has two layers.

First Layer - Color.white

Second Layer - Color.red

Now what I want to achieve is the ability to draw a circle that allows myself to see the first layer while the second layer is still red. Not simply draw a circle that is white.

Here is a picture of what I mean

enter image description here

I came across some previous code but it did not work, so I was hoping someone had the knowledge of Graphics2D to achieve this.

Here is the code and I leave the rest to you.

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();
Solution

  • You can use Area and Graphics.setClip

    Area a = new Area(yourRect);
a.subtract(new Area(yourCircle));
g.setClip(a);