JFrame内的绝对定位图形JPanel被空白部分阻塞

I was really intrigued by this idea, so I made another example, using a custom layout manager.

public class MyPuzzelBoard extends JPanel {

    public static final int GRID_X = 4;
    public static final int GRID_Y = 4;
    private BufferedImage image;

    public MyPuzzelBoard(BufferedImage image) {
        setLayout(new VirtualLayoutManager());
        setImage(image);

        addMouseListener(new MouseAdapter() {
            @Override
            public void mouseClicked(MouseEvent e) {
                if (e.getClickCount() == 2) {
                    removeAll();
                    generatePuzzel();
                } else {
                    Component comp = getComponentAt(e.getPoint());
                    if (comp != null && comp != MyPuzzelBoard.this) {
                        setComponentZOrder(comp, 0);
                        invalidate();
                        revalidate();
                        repaint();
                    }
                }
            }
        });
    }

    public void setImage(BufferedImage value) {
        if (value != image) {
            image = value;
            removeAll();
            generatePuzzel();
        }
    }

    public BufferedImage getImage() {
        return image;
    }

    protected float generateRandomNumber() {
        return (float) Math.random();
    }

    protected void generatePuzzel() {
        BufferedImage image = getImage();

        if (image != null) {
            int imageWidth = image.getWidth();
            int imageHeight = image.getHeight();

            int clipWidth = imageWidth / GRID_X;
            int clipHeight = imageHeight / GRID_Y;
            for (int x = 0; x < GRID_X; x++) {
                for (int y = 0; y < GRID_Y; y++) {

                    float xPos = generateRandomNumber();
                    float yPos = generateRandomNumber();
                    Rectangle bounds = new Rectangle((x * clipWidth), (y * clipHeight), clipWidth, clipHeight);
                    MyPiece piece = new MyPiece(image, bounds);
                    add(piece, new VirtualPoint(xPos, yPos));

                }
            }
        }

        invalidate();
        revalidate();
        repaint();
    }

    public class VirtualPoint {

        private float x;
        private float y;

        public VirtualPoint(float x, float y) {
            this.x = x;
            this.y = y;
        }

        public float getX() {
            return x;
        }

        public float getY() {
            return y;
        }

        public void setX(float x) {
            this.x = x;
        }

        public void setY(float y) {
            this.y = y;
        }
    }

    public class VirtualLayoutManager implements LayoutManager2 {

        private Map<Component, VirtualPoint> mapConstraints;

        public VirtualLayoutManager() {
            mapConstraints = new WeakHashMap<>(25);
        }

        @Override
        public void addLayoutComponent(Component comp, Object constraints) {
            if (constraints instanceof VirtualPoint) {
                mapConstraints.put(comp, (VirtualPoint) constraints);
            }
        }

        @Override
        public Dimension maximumLayoutSize(Container target) {
            return new Dimension(Integer.MAX_VALUE, Integer.MAX_VALUE);
        }

        @Override
        public float getLayoutAlignmentX(Container target) {
            return 0.5f;
        }

        @Override
        public float getLayoutAlignmentY(Container target) {
            return 0.5f;
        }

        @Override
        public void invalidateLayout(Container target) {
        }

        @Override
        public void addLayoutComponent(String name, Component comp) {
        }

        @Override
        public void removeLayoutComponent(Component comp) {
            mapConstraints.remove(comp);
        }

        @Override
        public Dimension preferredLayoutSize(Container parent) {
            return new Dimension(400, 400);
        }

        @Override
        public Dimension minimumLayoutSize(Container parent) {
            return preferredLayoutSize(parent);
        }

        @Override
        public void layoutContainer(Container parent) {
            int width = parent.getWidth();
            int height = parent.getHeight();

            for (Component comp : parent.getComponents()) {

                VirtualPoint p = mapConstraints.get(comp);
                if (p != null) {

                    int x = Math.round(width * p.getX());
                    int y = Math.round(height * p.getY());

                    Dimension size = comp.getPreferredSize();

                    x = Math.min(x, width - size.width);
                    y = Math.min(y, height - size.height);

                    comp.setBounds(x, y, size.width, size.height);

                }
            }
        }
    }
}

基本上，这使用虚拟"坐标系，而不是提供以像素为单位的绝对 x/y 位置，而是以父容器的百分比形式提供它们.现在，老实说，转换回绝对定位并不需要太多，这样，您还可以获得布局缩放.