Question

i used class to make rounded border

the class is :

public class RoundedBorder implements Border {
        int radius;

        public RoundedBorder(int radius) {
            this.radius = radius;
        }
    @Override
        public Insets getBorderInsets(Component c) {
            return new Insets(this.radius/2, this.radius, this.radius/2, this.radius);
        }
    @Override
        public boolean isBorderOpaque() {
            return true;
        }
    @Override
        public void paintBorder(Component c, Graphics g, int x, int y, int width, int height) {
            Graphics2D graphics = (Graphics2D) g;
            graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);

            g.drawRoundRect(x,y,width-1,height-1,radius,radius);           
        }
    }

and for button i used :

JTextField login_nickname = new JTextField();

login_nickname.setBorder(new RoundedBorder(10));
login_nickname.setPreferredSize(new Dimension(150, 25));

and it’s worked fine , but i want remove unused background outside rounded border in corner , i attached image to explain more what i mean,

thank you

Answer 1

I would do something like this in paintBorder():

@Override
 public void paintBorder(Component c, Graphics g, int x, int y, int width, int height) {
     Graphics2D graphics = (Graphics2D) g;
     graphics.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
     if (c.getParent() != null) {
         Color bc = g.getColor();
         g.setColor(c.getParent().getBackground());
         for (int r = 0; r<radius;r++){
            g.drawRoundRect(x, y, width - 1, height - 1, r, r);
         }
         g.setColor(bc);
     }
     g.drawRoundRect(x, y, width - 1, height - 1, radius, radius);
 }

If the component has some parent container, i would draw first the border with the background color, then on top of it – my round border.