java - 将 Graphics2D 转换为 ImageIcon

Question

根据先前提出的问题 Java Swing selecting a panel ，我正在尝试将示例中显示的图标更改为小型化的 Graphics2D 对象。

我的程序将有几个面板，每个面板中都有一个 Graphics2D 绘图，单击面板时，附近会出现一个放大的 View (也如其他问题答案中的示例所示。

我现在的问题是从每个面板中的 Graphics2D 绘图生成一个小图标。目前，我在创建和使用图标时遇到问题。

public class BiomorphPanel extends JPanel{

PointCalc pc = new PointCalc();
private JLabel label = new JLabel();
private ImageIcon icon;

public JLabel getLabel() {
    return label;
}

public BiomorphPanel(){
    this.add(label);
}

private void doDrawing(Graphics g){

    Graphics2D g2d = (Graphics2D) g;
    //g2d.scale(0.1, 0.1);
    BufferedImage img = new BufferedImage(31, 31, BufferedImage.TYPE_INT_RGB);
    Graphics2D g2dIcon = (Graphics2D) img.getGraphics();

    drawAll(g2d);
    drawAll(g2dIcon);

    g2dIcon.setColor(Color.BLACK);
    g2dIcon.fillRect(0, 0, 31, 31);
    g2dIcon.drawImage(img, null, 0, 0);
    icon = new ImageIcon(img);
    //icon = new ImageIcon(gra);
}

 @Override
 public void paintComponent(Graphics g) {       
     Graphics2D g2 = (Graphics2D) g;
     //scaling and translating to fit into mini panels in GUI
    // g2.scale(0.15, 0.15);
     //g2.translate(-100.0, 0.0);
     super.paintComponent(g2);
     doDrawing(g2);
    }    

 public ImageIcon getIcon(){
     return icon;
 }

 public void drawAll(Graphics2D g2d){
        //draw head
        Polygon hPoints = pc.getHeadPoints();
        g2d.drawPolygon(hPoints);

        //draw eyes
        Pair<Polygon, Polygon> ePoints = pc.getAllEyePoints();
        g2d.drawPolygon(ePoints.x);
        g2d.drawPolygon(ePoints.y);

        //draw eyebrows
        Pair<HashMap<Integer, Pair<Integer, Integer>>, HashMap<Integer, Pair<Integer, Integer>>> ebPoints = pc.getEyebrowPoints();
        g2d.drawLine(ebPoints.x.get(0).x, ebPoints.x.get(0).y, ebPoints.x.get(1).x, ebPoints.x.get(1).y);
        g2d.drawLine(ebPoints.y.get(0).x, ebPoints.y.get(0).y, ebPoints.y.get(1).x, ebPoints.y.get(1).y);

        //draw nose
        HashMap<Integer, Pair<Integer, Integer>> nPoints = pc.getNosePoints();
        g2d.drawLine(nPoints.get(0).x, nPoints.get(0).y, nPoints.get(1).x, nPoints.get(1).y);
        g2d.drawLine(nPoints.get(1).x, nPoints.get(1).y, nPoints.get(2).x, nPoints.get(2).y);

        //draw mouth
        Pair<HashMap<Integer, Pair<Integer, Integer>>, HashMap<Integer, Pair<Integer, Integer>>> mPoints = pc.getMouthPoints();
        g2d.drawLine(mPoints.x.get(0).x, mPoints.x.get(0).y, mPoints.x.get(1).x, mPoints.x.get(1).y);
        g2d.drawLine(mPoints.x.get(1).x, mPoints.x.get(1).y, mPoints.x.get(2).x, mPoints.x.get(2).y);

        g2d.drawLine(mPoints.y.get(0).x, mPoints.y.get(0).y, mPoints.y.get(1).x, mPoints.y.get(1).y);
        g2d.drawLine(mPoints.y.get(1).x, mPoints.y.get(1).y, mPoints.y.get(2).x, mPoints.y.get(2).y);

 }

}

上面是我尝试创建 ImageIcon 的地方。

public class ListDisplayPanel extends Component{

//private static final Icon icon = UIManager.getIcon("html.pendingImage");

private ListPanel listPanel = new ListPanel();
private BiomorphPanel displayPanel1 = new BiomorphPanel();
private BiomorphPanel displayPanel2 = new BiomorphPanel();
private Icon icon = displayPanel1.getIcon();
private JPanel dpHold = new JPanel();

private class ListPanel extends JPanel {

    private static final int N = 5;
    private DefaultListModel dlm = new DefaultListModel();
    private JList list = new JList(dlm);

    public ListPanel() {
        super(new GridLayout());
        for (int i = 0; i < N * N; i++) {
            String name = "Cell-" + String.format("%02d", i);
            dlm.addElement(name);
        }
        list.setSelectionMode(ListSelectionModel.SINGLE_SELECTION);
        list.setLayoutOrientation(JList.HORIZONTAL_WRAP);
        list.setVisibleRowCount(N);
        list.setCellRenderer(new ListRenderer());
        list.addListSelectionListener(new SelectionHandler());
        this.add(list);
    }

    private class ListRenderer extends DefaultListCellRenderer {

        @Override
        public Component getListCellRendererComponent(JList list,
                Object value, int index, boolean isSelected, boolean cellHasFocus) {
            JLabel label = (JLabel) super.getListCellRendererComponent(
                    list, value, index, isSelected, cellHasFocus);
            label.setBorder(BorderFactory.createEmptyBorder(N, N, N, N));
            label.setIcon(icon);
            label.setHorizontalTextPosition(JLabel.CENTER);
            label.setVerticalTextPosition(JLabel.BOTTOM);
            return label;
        }
    }

    private class SelectionHandler implements ListSelectionListener {

        @Override
        public void valueChanged(ListSelectionEvent e) {
            if (!e.getValueIsAdjusting()) {
                displayPanel1.getLabel().setText((String) dlm.getElementAt(e.getLastIndex()));
                displayPanel2.getLabel().setText((String) dlm.getElementAt(e.getLastIndex()));
            }
        }
    }
}

private void display() {
    JFrame f = new JFrame("Test");
    f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    JSplitPane jsp = new JSplitPane();
    jsp.setLeftComponent(new JScrollPane(listPanel));
    JSplitPane jsp2 = new JSplitPane();
    jsp2.setTopComponent(displayPanel1);
    jsp2.setBottomComponent(displayPanel2);
    jsp.setRightComponent(jsp2);
    f.add(jsp);
    f.pack();
    f.setLocationRelativeTo(null);
    f.setVisible(true);
}

public static void main(String[] args) {
    /*EventQueue.invokeLater(() ->*/ {
        new ListDisplayPanel().display();
    };
}
}

这是我尝试使用创建的图标的地方。当我运行类(class)时，菜单中的每个“单元格”都没有图标出现。图标创建不正确还是使用不正确？我说不出来。

谢谢

Answer 1

关键是创建一个实现 Icon 的类界面。覆盖图标的 paintIcon()方法，它接收合适的图形上下文，并在那里进行渲染。使用 Component 参数检索属性，使用 x 和 y 参数利用布局几何。查看完整示例here ;可以找到更多 here .