如何在Java中旋转图形

I have drawn some Graphics in a JPanel, like circles, rectangles, etc.

我在JPanel中绘制了一些图形，如圆形，矩形等。

But I want to draw some Graphics rotated a specific degree amount, like a rotated ellipse. What should I do?

但我想绘制一些特定程度旋转的图形，如旋转的椭圆。我该怎么办？

2 个解决方案

#1

If you are using plain Graphics, cast to Graphics2D first:

如果您使用的是普通图形，请首先转换为Graphics2D：

Graphics2D g2d = (Graphics2D)g;

To rotate an entire Graphics2D:

要旋转整个Graphics2D：

g2d.rotate(Math.toRadians(degrees));
//draw shape/image (will be rotated)

To reset the rotation (so you only rotate one thing):

要重置旋转（所以你只旋转一件事）：

AffineTransform old = g2d.getTransform();
g2d.rotate(Math.toRadians(degrees));
//draw shape/image (will be rotated)
g2d.setTransform(old);
//things you draw after here will not be rotated

Example:

例：

class MyPanel extends JPanel {
    @Override
    public void paintComponent(Graphics g) {
        super.paintComponent(g);
        Graphics2D g2d = (Graphics2D)g;
        AffineTransform old = g2d.getTransform();
        g2d.rotate(Math.toRadians(degrees));
        //draw shape/image (will be rotated)
        g2d.setTransform(old);
        //things you draw after here will not be rotated
    }
}

#2

In your paintComponent() overridden method, cast the Graphics argument to Graphics2D, call rotate() on this Graphics2D, and draw your ellipse.

在paintComponent（）重写方法中，将Graphics参数强制转换为Graphics2D，在此Graphics2D上调用rotate（），然后绘制椭圆。

#1