java - 组合框箭头按钮根据 nimbus LaF 中的字体大小进行拉伸(stretch)

Question

我在我的应用程序中使用 JCombobox 和 Nimbus LaF。我已经针对不同的状态覆盖了 Combobox 的 Backgroundpainter 和 ArrowButton 的 Foregroundpainter 。油漆工们工作得很好。但是当我增加字体大小时，Combobox 的箭头按钮会拉伸(stretch)，看起来不太好。

如何使其不可拉伸(stretch)？

我使用了 Nimbus LaF 本身的画家，我必须提供自己的 PaintContext。

这是显示问题的代码。

public class ComboTest {

    public ComboTest(){

      String labels[] = { "A", "B", "C", "D" };

    JFrame frame = new JFrame("ComboBox Demo");

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

    JComboBox comboBox = new JComboBox(labels);

    frame.add(comboBox, BorderLayout.NORTH);

    frame.setSize(300, 100);

    frame.setVisible(true);
        }

    public static void main(String[] args)
    {

        try {
             UIManager.setLookAndFeel(NimbusLookAndFeel.class.getName()); 

           }

        catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
       }

    UIManager.getLookAndFeelDefaults().put("defaultFont", new Font("Segoe UI", Font.PLAIN,16));

// if i put the different font size than it is strecthing, with the size 12 it looks good.

    //UIManager.getLookAndFeelDefaults().put("defaultFont", new Font("SegoeUI",Font.PLAIN,12));

    UIManager.getLookAndFeelDefaults().put("ComboBox:\"ComboBox.arrowButton"[Pressed].foregroundPainter", new ComboArrowPainter(1));

    javax.swing.SwingUtilities.invokeLater(new Runnable() {

    public void run() { 

            new ComboTest();

      }
         });
    }

    }

这是 ArrowPainter 的类(class)，它是我从 Nimbus 获取的

public class ComboArrowPainter extends AbstractRegionPainter {

    static final int FOREGROUND_PRESSED = 1;

      private int state; //refers to one of the static final ints above

      private PaintContext ctx;
      //the following 4 variables are reused during the painting code of the layers

      private Path2D path = new Path2D.Float();

      private Color color31 = decodeColor("textForeground", 0.0f, -0.6357143f, 0.45098037f, 0);

      public ComboArrowPainter(int state) {

    super();

         this.state = state;

          this.ctx = new PaintContext(new Insets(6,10,6,10), new Dimension(19,19), false);;
      }

    private Object[] componentColors;

      @Override

      protected void doPaint(Graphics2D g, JComponent c, int width, int height, Object[] extendedCacheKeys) {

     //populate componentColors array with colors calculated in getExtendedCacheKeys call

          componentColors = extendedCacheKeys;

          paintForegroundPressed(g); 

         }

    @Override

      protected final PaintContext getPaintContext() {

          return ctx;

      }

      private void paintForegroundPressed(Graphics2D g) {

          path = decodePath8();

          g.setPaint(color31);

          g.fill(path);

      }

      private Path2D decodePath8() {

          path.reset();

          path.moveTo(decodeX(1.0242647f), decodeY(1.3526785f));

          path.lineTo(decodeX(2.0f), decodeY(0.8333333f));

          path.lineTo(decodeX(2.0f), decodeY(1.8571429f));

          path.lineTo(decodeX(1.0242647f), decodeY(1.3526785f));

          path.closePath();

          return path;

      }

    }

Answer 1

幸运的是，我已经找到了解决办法。我已经计算了相对于字体大小的组件大小。我们已使用该值作为 Paintcontext。这是更新后的 Painter 类的构造函数，其余的将是相同的。

public ComboArrowPainter(int state, int FontSize) {
             super();
             this.state = state;
             double value = FontSize*1.31031746;
             int topBottomInsssetValue =(int) Math.ceil((value)/2);
             this.ctx = new PaintContext(new Insets(6,topBottomInsssetValue,6,topBottomInsssetValue), new Dimension(19,19), false); 

    }