Caret and TextLayout
import java.awt.Color;
import java.awt.Dimension;
import java.awt.Font;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.Shape;
import java.awt.event.MouseAdapter;
import java.awt.event.MouseEvent;
import java.awt.event.MouseMotionAdapter;
import java.awt.event.WindowAdapter;
import java.awt.event.WindowEvent;
import java.awt.font.FontRenderContext;
import java.awt.font.TextHitInfo;
import java.awt.font.TextLayout;
import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import javax.swing.JFrame;
import javax.swing.JPanel;
public class TextLayoutPanel extends JPanel {
TextLayout layout;
FontRenderContext frc;
Font font;
Rectangle2D rect;
float rx, ry, rw, rh;
TextHitInfo hitInfo;
Color caretColor;
int hit1, hit2;
int w, h;
public TextLayoutPanel() {
setBackground(Color.white);
setForeground(Color.black);
setSize(400, 200);
addMouseListener(new MouseHandler());
addMouseMotionListener(new MouseMotionHandler());
w = getWidth();
h = getHeight();
String text = "Java Source and Support";
font = new Font("Arial", Font.PLAIN, 36);
frc = new FontRenderContext(null, false, false);
layout = new TextLayout(text, font, frc);
rx = (float) (w / 2 - layout.getBounds().getWidth() / 2);
ry = (float) 3 * h / 4;
rw = (float) (layout.getBounds().getWidth());
rh = (float) (layout.getBounds().getHeight());
rect = new Rectangle2D.Float(rx, ry, rw, rh);
caretColor = getForeground();
}
public void update(Graphics g) {
g.clearRect(0, 0, getWidth(), getHeight());
paintComponent(g);
}
public void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D) g;
AffineTransform at = AffineTransform.getTranslateInstance(rx, ry);
Shape hilight = layout.getLogicalHighlightShape(hit1, hit2);
hilight = at.createTransformedShape(hilight);
g2.setColor(Color.lightGray);
g2.fill(hilight);
g2.setColor(Color.black);
layout.draw(g2, rx, ry);
// Draw caret
Shape[] caretShapes = layout.getCaretShapes(hit1);
Shape caret = at.createTransformedShape(caretShapes[0]);
g2.setColor(caretColor);
g2.draw(caret);
}
public int getHitLocation(int mouseX, int mouseY) {
hitInfo = layout.hitTestChar(mouseX, mouseY, rect);
return hitInfo.getInsertionIndex();
}
class MouseHandler extends MouseAdapter {
public void mouseClicked(MouseEvent e) {
caretColor = getForeground();
hit1 = getHitLocation(e.getX(), e.getY());
hit2 = hit1;
repaint();
}
public void mousePressed(MouseEvent e) {
caretColor = getForeground();
hit1 = getHitLocation(e.getX(), e.getY());
hit2 = hit1;
repaint();
}
public void mouseReleased(MouseEvent e) {
hit2 = getHitLocation(e.getX(), e.getY());
repaint();
}
}
class MouseMotionHandler extends MouseMotionAdapter {
public void mouseDragged(MouseEvent e) {
caretColor = getBackground();
hit2 = getHitLocation(e.getX(), e.getY());
repaint();
}
}
public static void main(String arg[]) {
JFrame frame = new JFrame();
frame.setBackground(Color.white);
frame.addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e) {
System.exit(0);
}
});
frame.getContentPane().add("Center", new TextLayoutPanel());
frame.pack();
frame.setSize(new Dimension(400, 300));
frame.setVisible(true);
}
}
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