java - 更改 Graphic2D 形状

Question

嘿，我想创建一个程序，你可以在其中绘制圆形、矩形、直线等多种形状。当我单击圆形按钮并绘制圆形(1)时，然后当我单击矩形时，它应该只绘制矩形，而不是圆形和矩形(2) ) ，当我单击“直线”时，它应该只绘制直线而不是“圆形”、“矩形”和“直线”(3)。

public class Images extends JComponent {


    private Image image;

    private Graphics2D g2;

    private int currentX, currentY, oldX, oldY;

    public Images() {
        setDoubleBuffered(false);
    }

    protected void paintComponent(Graphics g) {
        if (image == null) {

            image = createImage(getSize().width, getSize().height);
            g2 = (Graphics2D) image.getGraphics();

            g2.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);

            clear();
        }
        g.drawImage(image, 0, 0, null);
    }


    public void line() {
        currentX = 0;
        currentY = 0;
        oldX = 0;
        oldY = 0;

        addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent e) {
                oldX = e.getX();
                oldY = e.getY();
            }
        });

        addMouseListener(new MouseAdapter() {
            public void mouseReleased(MouseEvent e) {
                currentX = e.getX();
                currentY = e.getY();
                g2.draw(new Line2D.Double(oldX, oldY, currentX, currentY));
                repaint();
            }
        });
    }

    public void rectangle() {
        currentX = 0;
        currentY = 0;
        oldX = 0;
        oldY = 0;
        addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent e) {
                oldX = e.getX();
                oldY = e.getY();
            }
        });
        addMouseListener(new MouseAdapter() {
            public void mouseReleased(MouseEvent e) {
                currentX = e.getX();
                currentY = e.getY();
                g2.draw(new Rectangle2D.Double(oldX, oldY, currentX - oldX, currentY - oldY));
                repaint();
            }
        });
    }
    public void circle() {
        currentX = 0;
        currentY = 0;
        oldX = 0;
        oldY = 0;
        addMouseListener(new MouseAdapter() {
            public void mousePressed(MouseEvent e) {
                oldX = e.getX();
                oldY = e.getY();
            }
        });
        addMouseListener(new MouseAdapter() {
            public void mouseReleased(MouseEvent e) {
                currentX = e.getX();
                currentY = e.getY();
                g2.draw(new Ellipse2D.Double(oldX, oldY, (currentX - oldX), (currentX - oldX)));
                repaint();
            }});}}

Answer 1

您将获得所有以前选择的形状，因为它们的 mousedown/mouseup 事件仍然绑定(bind)。

解决此问题的一个简单方法是跟踪您的 MouseAdapter(在绑定(bind)它们时将它们添加到列表中)并在切换工具时将其删除(随后清除列表)。