Combobox ArrowButton is strecthing respective to the font size in nimbus LaF

Question

I am using JCombobox with Nimbus LaF in my application. I have override the Backgroundpainter of Combobox and Foregroundpainter of ArrowButton for different states. The painters are working fine. but when I increase the size of the font, the arrowbutton of Combobox is stretching and it is not looking good.

How to make it unstretchable?

I have used the painters from Nimbus LaF itself there i have to provide my own paintContext.

Here is the code that shows the problem.

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();

      }
         });
    }

    }

Here is the class for ArrowPainter, which i took from Nimbus

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

Fortunately, I have found the solution. I have calculated the component size respective to the fontsize. We have used that value as our Paintcontext. Here is the updated constructor of painter class remaining will be the same.

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); 

    }