Java Swing

Creating Your Own Border

Creating your own border is simple when you extend the AbstractBorder class. You need to define three things: whether the border is opaque, what its insets are, and how to draw the border. To accomplish this, you must implement paintBorder(), both isBorderOpaque() methods, and getBorderInsets(). The hard part of coming up with your own border is doing something creative with the Graphics primitives in the paintBorder() method. A reminder: make sure that you do not paint inside the insets region that you define for yourself. Otherwise, you could be painting over the component you intend to border.

Let’s take a look at a simple border:

// CurvedBorder.java // import java.awt.*; import javax.swing.border.*; public class CurvedBorder extends AbstractBorder { private Color wallColor = Color.gray; private int sinkLevel = 10; public CurvedBorder() { } public CurvedBorder(int sinkLevel) { this.sinkLevel = sinkLevel; } public CurvedBorder(Color wall) { this.wallColor = wall; } public CurvedBorder(int sinkLevel, Color wall) { this.sinkLevel = sinkLevel; this.wallColor = wall; } public void paintBorder(Component c, Graphics g, int x, int y, int w, int h) { g.setColor(getWallColor()); // Paint a tall wall around the component for (int i = 0; i < sinkLevel; i++) { g.drawRoundRect(x+i, y+i, w-i-1, h-i-1, sinkLevel-i, sinkLevel); g.drawRoundRect(x+i, y+i, w-i-1, h-i-1, sinkLevel, sinkLevel-i); g.drawRoundRect(x+i, y, w-i-1, h-1, sinkLevel-i, sinkLevel); g.drawRoundRect(x, ...