Java中只有中心点和半径的包围盒算法

我正在尝试使用fillOval命令在Java中创建一个圆。用户输入圆的中心坐标和半径，但我不知道如何找到圆角命令的高度和宽度

import java.util.*;
import java.awt.*;

public class Circles {
  public static final Scanner Console = new Scanner(System.in);
  public static void main(String args[]) {

DrawingPanel panel = new DrawingPanel(400,300);
Graphics g = panel.getGraphics();

//print the beginning statement of the main method
System.out.println("");

//ask the user for the center and radius for the first circle
System.out.println("Enter the x-value for the center of the first circle:    ");
double x1 = Console.nextDouble();
System.out.println("Enter the y-value for the center of the first circle: ");
double y1 = Console.nextDouble();
System.out.println("Enter the radius for the first circle: ");
double rad1 = Console.nextDouble();

//calculate the height and width of the first circle


//ask the user for the center and radius for the second circle
System.out.println("Enter the x-value for the center of the second circle: ");
double x2 = Console.nextDouble();
System.out.println("Enter the y-value for the center of the second circle: ");
double y2 = Console.nextDouble();
System.out.println("Enter the radius for the second circle: ");
double rad2 = Console.nextDouble();

//calculate the height and width of the second circle


//ask the user for the center and radius for the third circle
System.out.println("Enter the x-value for the center of the third circle: ");
double x3 = Console.nextDouble();
System.out.println("Enter the y-value for the center of the third circle: ");
double y3 = Console.nextDouble();
System.out.println("Enter the radius for the third circle: ");
double rad3 = Console.nextDouble();

//calculate the height and width of the third circle


//use the fillOval method to draw each circle
//fillOval(int x, int y, int width, int height)

---

到目前为止，我只有这些。我只是不知道如何获得高度和宽度。

也许这个简单的小方法会帮你一点忙

/**
 * Draws a circle on any Swing Component based off of the center of the circle rather than the top left corner of
 * the rectangle that the circle resides in.<pre>
 * 
 * <b>Example Usage:</b>
 * 
 *      DrawCircle(jLabel1, Color.RED, jLabel1.getWidth()/2, jLabel1.getHeight()/2, 40, 2);
 * </pre>
 *
 * @param ctrl (Any Swing Object) The variable name of the JComponent to draw on.<br> 
 * @param color (Color) (Optional - default is the current graphics color if null is passed) The color of the line
 * which makes the circle.<br>
 * @param x (Integer) The X location (in pixels) of where the center of circle is to be located.<br>
 * @param y (Integer) The Y location (in pixels) of where the center of circle is to be located.<br>
 * @param radius (Integer) The Radius of the circle in pixels (not the diameter). Radius is: (diameter/2).<br>
 * @param thickness (Integer) The thickness of the circle line (in pixels).
 */
public static void drawMyCircle(JComponent ctrl, Color color, int x, int y, int radius, int thickness) {
    Graphics2D g2 = (Graphics2D) ctrl.getGraphics();
    int diameter = radius * 2;
    g2.setColor(color);
    g2.setStroke(new BasicStroke(thickness));
    //shift x and y by the radius of the circle in order to correctly center it
    g2.drawOval(x - radius, y - radius, diameter, diameter); 
    g2.dispose();
    ctrl.revalidate();
}

/**
*基于圆的中心而不是旋转的左上角，在任何回转组件上绘制圆
*圆所在的矩形。
* 
*用法示例：
* 
*DrawCircle（jLabel1，Color.RED，jLabel1.getWidth（）/2，jLabel1.getHeight（）/2,40,2）；
* 
*
*@param ctrl（任何Swing对象）要绘制的JComponent的变量名。

*@param color（color）（可选-如果传递null，则默认为当前图形颜色）线条的颜色
*这就是圆。

*@param x（整数）圆心所在的x位置（以像素为单位）。

*@param y（整数）圆心所在的y位置（以像素为单位）。

*@param radius（Integer）以像素为单位的圆半径（不是直径）。半径为：（直径/2）。

*@param thickness（Integer）圆线的厚度（以像素为单位）。
*/
公共静态空白drawMyCircle（JComponent ctrl、颜色、整数x、整数y、整数半径、整数厚度）{
Graphics2D g2=（Graphics2D）ctrl.getGraphics（）；
内径=半径*2；
g2.设置颜色（颜色）；
g2.设定行程（新基本行程（厚度））；
//将x和y移动圆的半径，以使其正确居中
g2.绘图椭圆（x-半径，y-半径，直径，直径）；
g2.dispose（）；
ctrl.revalidate（）；
}

---

将drawOval（）替换为fillOval（）。

好吧，圆的直径是半径的2倍，圆的宽度和高度等于直径，对吗？你的右边。我完全忽略了这一点。我显然是想让事情变得比实际更难。非常感谢。这很有帮助。现在它更有意义了。非常感谢。