How can I decorate the scroll bar?

[UltraBurstXD]

Hi JFormDesigner,

I wanted to know how can I decorate the scroll bar.

[DevCharly]

Don't know what you mean.
Can you provide more details?

If you want arrow buttons or wider scroll bars, see:
https://www.formdev.com/flatlaf/customizing/#scrollbar

[UltraBurstXD]

I mean changing the shape and decorate the scroll bar like this:

That above is Ubuntu's scroll bar
I don't want to make it to be like that... It was only a prototype.

[DevCharly]

You can subclass FlatScrollBarUI and implement own painting methods.

Here is a working example that paints round thumbs:

public class MyFlatScrollBarUI
	extends FlatScrollBarUI
{
	public static ComponentUI createUI( JComponent c ) {
		return new MyFlatScrollBarUI();
	}

	@Override
	protected void paintThumb( Graphics g, JComponent c, Rectangle thumbBounds ) {
		if( thumbBounds.isEmpty() || !scrollbar.isEnabled() )
			return;

		FlatUIUtils.setRenderingHints( (Graphics2D) g );

		int arc = Math.min( c.getWidth(), c.getHeight() ) - 2;
		g.setColor( thumbColor );
		g.fillRoundRect( thumbBounds.x + 1, thumbBounds.y + 1, thumbBounds.width - 2, thumbBounds.height - 2, arc, arc );
	}
}

Unfortunately it is currently not possible to paint the thumb in a darker color when the mouse is over it because the hover field is private. I'll change that for the next version.
The class must be public.

Then register the class in main after installing FlatLaf with:

UIManager.put( "ScrollBarUI", "com.myproject.MyFlatScrollBarUI" );

This looks like:

Anyway, I'm open to support different scrollbar styles out of the box.
Any suggestions are welcome 😉

[UltraBurstXD]

Thanks, DevCharly.

[DevCharly]

Since FlatLaf 0.36 it is possible to use different styles for scroll bars.
See https://www.formdev.com/flatlaf/customizing/#scrollbar_style