Gradient Background for JTextPane

[sachin upatil]

Hi,

I want Gradient Color background for JTextPane....

I tried this.

screen = JTextPane(){
     public void paintComponent(Graphics og){
               super.paintComponent(og);

               Graphics2D g =  (Graphics2D)og;
               
               GradientPaint gradient  =  new GradientPaint(0,0,color.gray,0,255,color.white,true);

               g.setPaint(gradient);
               g.fillRoundRect(0,0,470,255,30,30); 

     }

};

screen.setBound(500,160,470,255);
screen.setText("Write Introduction here.");

in this code gradient is working fine. But JTextPane is not showing any Text on it.

What is wrong with this code ?

[Campbell Ritchie]

What on earth does screen = JTextPane() { . . . mean? Have you got a method of that name or are you trying to create an anonymous class? In either case it looks as though you have a compiler error in it.

[pete stein]

Campbell Ritchie wrote:What on earth does screen = JTextPane() { . . . mean? Have you got a method of that name or are you trying to create an anonymous class? In either case it looks as though you have a compiler error in it.

Yep, and "color". To the OP, please post real code.

[pete stein]

Anyway, one solution is to put the JTextPane into a JScrollPane and set the gradient of the JViewport that holds the JTextPane. If you do this be sure to set the JTextPane's opaque property to false. Oh, and you probably want to avoid using null layout and setBounds.

For example:

import java.awt.*;
import javax.swing.*;

public class TextPaneGradient {
   private static void createAndShowUI() {
      JTextPane screen = new JTextPane();
      screen.setOpaque(false);

      JViewport viewport = new JViewport(){
         public void paintComponent(Graphics og) {
            super.paintComponent(og);
            Graphics2D g = (Graphics2D) og;
            g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, 
                     RenderingHints.VALUE_ANTIALIAS_ON);
            GradientPaint gradient = new GradientPaint(0, 0, Color.gray, 
                     0, getHeight(), Color.white, true);
            g.setPaint(gradient);
            g.fillRoundRect(0, 0, getWidth(), getHeight(), 30, 30);
         }

      };
      viewport.setPreferredSize(new Dimension(400, 300));
      viewport.add(screen);
      JScrollPane scrollpane = new JScrollPane();
      scrollpane.setViewport(viewport);

      JFrame frame = new JFrame("TextPaneGradient");
      frame.getContentPane().add(scrollpane);
      frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
      frame.pack();
      frame.setLocationRelativeTo(null);
      frame.setVisible(true);
   }

   public static void main(String[] args) {
      java.awt.EventQueue.invokeLater(new Runnable() {
         public void run() {
            createAndShowUI();
         }
      });
   }
}

[Darryl Burke]

pete's solution is good, but "fixes" the gradient background i.e. the background gradient won't scroll with the text pane.

It's sufficient to setOpaque(false) and paint the text pane's background before invoking the super implementation.

import java.awt.*;
import javax.swing.*;

public class TextPaneGradientBackground {

  public static void main(String[] args) {
    SwingUtilities.invokeLater(new Runnable() {

      @Override
      public void run() {
        new TextPaneGradientBackground().makeUI();
      }
    });
  }

  public void makeUI() {
    JTextPane textPane = new JTextPane() {

      @Override
      protected void paintComponent(Graphics g) {
        Paint paint = new GradientPaint(0, 0, Color.gray,
                0, getHeight(), Color.white, true);
        ((Graphics2D) g).setPaint(paint);
        g.fillRect(0, 0, getWidth(), getHeight());
        super.paintComponent(g);
      }
    };
    textPane.setOpaque(false);
    StringBuilder sb = new StringBuilder();
    for (int i = 0; i < 50; i++) {
      sb.append("The quick brown fox jumps over the lazy dog.  ");
    }
    textPane.setText(sb.toString());

    JFrame frame = new JFrame();
    frame.add(new JScrollPane(textPane));

    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.setSize(400, 400);
    frame.setLocationRelativeTo(null);
    frame.setVisible(true);
  }
}

To the OP: note that constructing a GradientPaint is computationally expensive and you are likely to see a surge in CU use during periods of frequent repainting, or even a slowdown and flickering/jerks on an older, slow computer.

[sachin upatil]

Thank you.