How to remove indents in the tabs JTabbedPane?

Question

How to remove the indents around icon tabs in JTabbedPane? i.e. what would this icon was on the full size of the tabs?

Answer 1

You can try next trick with getTabInsets() method of BasicTabbedPaneUI:

import java.awt.Insets;

import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JTabbedPane;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.plaf.basic.BasicTabbedPaneUI;

public class TestFrame extends JFrame {

    public TestFrame() {
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        init();
        pack();
        setVisible(true);
    }

    private void init() {
        try {
            UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
        } catch (ClassNotFoundException | InstantiationException
                | IllegalAccessException | UnsupportedLookAndFeelException e) {
            e.printStackTrace();
        }
        JTabbedPane pane = new JTabbedPane(JTabbedPane.BOTTOM);
        pane.addTab("", new ImageIcon(TestFrame.class.getResource("1111.png")), new JLabel("lbl"));
        pane.addTab("test2", new JLabel("lbl2"));
        pane.setFocusable(false);
        pane.setUI(new BasicTabbedPaneUI() {
            @Override
            protected Insets getTabInsets(int tabPlacement, int tabIndex) {
                return new Insets(0, 0, 0, 0);
            }
        });
        add(pane);
    }


    public static void main(String... strings) {
        new TestFrame();
    }

}

Also try calculateTabWidth() and calculateTabHeight().