更改 Graphics2D 形狀

Question

嘿，我想創建一個程序，您可以在其中繪制圓形，矩形，線條等多形。當我單擊圓形按鈕並繪制圓形（1）然后當我單擊矩形時，它應該只繪制矩形，而不是圓形和矩形（2），當我點擊了 Line 它應該只繪制 Line 而不是 Circle 和 Rectangle 和 Line(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

您將獲得所有之前選擇的形狀，因為它們的 mousedown/mouseup 事件仍然是綁定的。

解決此問題的一種直接方法是跟蹤您的 MouseAdapter（綁定它們時將它們添加到列表中）並在切換工具時刪除它們（隨后清除列表）。