sending Java 2d context to image file
i am currently creating a GUI that will allow me to open, draw on and save a image.
currently my implementation opens ,displays and writes on an jpeg image or simalar by using the graphics 2d method to overide the paint function of a jLabel. for example:
File file = new File (jFileChooser1.getSelectedFile().getAbsolutePath());
BufferedImage image = null;
try {
image = ImageIO.read(file);
} catch (IOException ex) {
ex.printStackTrace();
}
scaledHeight=500 ;
scaledWidth= 500;
int imageType = BufferedImage.TYPE_INT_RGB;
BufferedImage scaledBI = new BufferedImage(scaledWidth, scaledHeight, imageType);
Graphics2D g = scaledBI.createGraphics();
g.setComposite(AlphaComposite.Src);
g.drawImage(image, 0, 0, scaledWidth, scaledHeight, null);
g.dispose();
Graphics2D g1 = (Graphics2D) jLabel1.getGraphics();
g1.drawImage(scaledBI, 0, 0, scaledWidth, scaledHeight, null);
g1.dispose();
however im stuck at how to take the context of the jLabel and use it to draw a image for saving purposes. what i have been attempting is:
BufferedImage image = new BufferedImage(scaledWidth, scaledHeight, imageType);
Graphics2D g1 = (Graphics2D) jLabel1.getGraphics();
Graphics2D g2 = (Graphics2D) image.creatGraphics();
g2.setComposite(AlphaComposite.Src);
g2=g1;
this method has been returning a result but when the file it apppears totally black.
is my thinking correct and what is needed to move the context of a component to an image?
[1599 byte] By [
t_k_na] at [2007-11-26 13:23:21]
# 3
import java.awt.*;
import java.awt.font.*;
import java.awt.geom.*;
import java.awt.image.BufferedImage;
import java.io.*;
import javax.imageio.ImageIO;
import javax.swing.*;
public class YourImage extends JPanel {
BufferedImage image;
Rectangle locater;
public YourImage(BufferedImage src) {
image = getScaledImage(src, 200, 200);
locater = new Rectangle(200, 200);
}
protected void paintComponent(Graphics g) {
super.paintComponent(g);
Graphics2D g2 = (Graphics2D)g;
g2.setRenderingHint(RenderingHints.KEY_TEXT_ANTIALIASING,
RenderingHints.VALUE_TEXT_ANTIALIAS_ON);
g2.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BICUBIC);
int w = getWidth();
int h = getHeight();
int x = (w - image.getWidth())/2;
int y = (h - image.getHeight())/2;
locater.x = x;
locater.y = y;
g2.drawImage(image, x, y, this);
Font font = g2.getFont().deriveFont(24f);
g2.setFont(font);
FontRenderContext frc = g2.getFontRenderContext();
String s = "hello world";
float width = (float)font.getStringBounds(s, frc).getWidth();
LineMetrics lm = font.getLineMetrics(s, frc);
float sx = (w - width)/2;
float sy = (h + lm.getAscent())/2 - lm.getDescent();
g2.setPaint(Color.red);
g2.drawString(s, sx, sy);
}
private BufferedImage getScaledImage(BufferedImage src, int w, int h) {
BufferedImage image = new BufferedImage(w, h, src.getType());
double xScale = (double)w / src.getWidth();
double yScale = (double)h / src.getHeight();
// To avoid distortion: choose fit or fill scale option.
double scale = Math.min(xScale, yScale);// scale to fit
//Math.max(xScale, yScale);// scale to fill
// Center scaled image.
double x = (w - scale*src.getWidth())/2;
double y = (h - scale*src.getHeight())/2;
AffineTransform at = AffineTransform.getTranslateInstance(x, y);
at.scale(scale, scale);
Graphics2D g2 = image.createGraphics();
g2.setPaint(getBackground());
g2.fillRect(0,0,w,h);
g2.drawRenderedImage(src, at);
g2.dispose();
return image;
}
private void save() {
// Do this on a background thread.
Thread thread = new Thread(new Runnable() {
public void run() {
// Wait a bit so the ui can be rendered and settle down.
try {
Thread.sleep(3000);
} catch(InterruptedException e) {
System.out.println("interrupted");
}
// Make a BufferedImage of the ui that we can save.
int w = locater.width;
int h = locater.height;
BufferedImage save = new BufferedImage(w, h, image.getType());
Graphics2D g2 = save.createGraphics();
g2.translate(-locater.x, -locater.y);
// Have the ui draw itself into our new BufferedImage.
paint(g2);
g2.dispose();
// Save to file.
try {
ImageIO.write(save, "jpg", new File("yourImage.jpg"));
} catch(IOException e) {
System.out.println("write error: " + e.getMessage());
}
}
});
thread.setPriority(Thread.NORM_PRIORITY);
thread.start();
}
public static void main(String[] args) throws IOException {
BufferedImage image = ImageIO.read(new File("images/cougar.jpg"));
final YourImage yourImage = new YourImage(image);
JFrame f = new JFrame();
f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
f.getContentPane().add(yourImage);
f.setSize(400,400);
f.setLocation(200,200);
f.setVisible(true);
// For the EDT after we leave main.
EventQueue.invokeLater(new Runnable() {
public void run() {
yourImage.save();
}
});
}
}
