如何在Java中旋转图形 [英] How to rotate Graphics in Java

问题描述

我在 JPanel 中绘制了一些图形，例如圆形，矩形等。

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

但是我想要绘制一些图形旋转一定的度数，如旋转的椭圆。我应该怎么做？

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

推荐答案

如果您使用的是 Graphics 转换为 Graphics2D first：

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

Graphics2D g2d = (Graphics2D)g;

旋转整个 Graphics2D ：

To rotate an entire Graphics2D:

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

重置旋转你只能旋转一个东西）：

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

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

示例：

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
    }
}

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