DrawOval（）位于一个点之上

Question

I use DrawOval function to draw a circle on top of a point in my Java project:

g2d.drawOval(instruction.getX(), instruction.getY(), instruction.getWidth(), instruction.getHeight());

The problem is that my circle is drawn such that the target point is outside the circle instead of at the center.

I tried to illustrate what happens on the left and what I want to have happen on the right:

I don't have any experience with drawing in Java, how do I solve this?

Answer 1

The oval is drawing at the give point so that it's top, left corner is at the x/y position. You need to offset the x/y by half the width/height...

int width  = instruction.getWidth();
int height = instruction.getHeight();
g2d.drawOval(instruction.getX() - (width / 2), instruction.getY() - (height / 2), width, height);

Check Graphics#drawOval for more details