Few days ago I did some image manipulation tasks like resizing, cropping, etc. java awt provides some useful functionality to do this type of tasks. Here I am going to share how I accomplish the tasks and finally and ImageUtility Class which you can use in your project.
Image Resizing
First read the image with the ImageIO which returns a BufferedImage. Then create another BufferedImage instance with the new width, height and image type.
BufferedImage originalImage = ImageIO.read(imageFile);
BufferedImage scaledBI = new BufferedImage(100, 100, BufferedImage.TYPE_INT_RGB);
Now get the Graphics2D component of the new scaled image and draw it.
g.drawImage(originalImage, 0, 0, 100, 100, null);
g.dispose();
If you want to preserve the image quality, add following line of code before disposing the graphics component.
g.setComposite(AlphaComposite.Src);
g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g.setRenderingHint(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
It's simple, is not it?
Image Croping
Read the image with ImageIO as stated previously and get the sub image of the original image.
BufferedImage originalImage = ImageIO.read(imageFile);
originalImage .getSubimage(0,0, 100, 100);
First two parameter of the getSubimage method is the x,y coordinate, from where you want to begin cropping.
Get Byte Array of an Image
Sometimes you need this specially when you want to save an image in database in blob data type . We can get byte[] of an image with the help of ByteArrayOutputStream and ImageIO class.
BufferedImage originalImage = ImageIO.read(imageFile);
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write(originalImage , getImageExtension(), baos);
//getImageExtension method is stated later
baos.flush();
byte[] imageData = baos.toByteArray();
baos.close();
ImageUtility.java
All the above actions can be encapsulated into a simple ImageUtility class.
import java.awt.AlphaComposite;
import java.awt.Dimension;
import java.awt.Graphics2D;
import java.awt.Image;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import org.openide.util.Exceptions;
/**
*
* @author ratul
*/
public class ImageUtility
{
private File imageFile;
private BufferedImage image;
public ImageUtility()
{
}
public ImageUtility(File imageFile)
{
try
{
this.imageFile = imageFile;
image = ImageIO.read(imageFile);
}
catch (IOException ex)
{
Exceptions.printStackTrace(ex);
}
}
public ImageUtility(File imageFile, BufferedImage image)
{
this.imageFile = imageFile;
this.image = image;
}
public File getImageFile()
{
return imageFile;
}
public void setImageFile(File imageFile)
{
this.imageFile = imageFile;
}
public BufferedImage getImage()
{
return image;
}
public void setImage(BufferedImage image)
{
this.image = image;
}
public String getImageExtension()
{
String fName = imageFile.getName();
return fName.substring(fName.indexOf(".")+1, fName.length());
}
public BufferedImage getResizedCopy(int scaledWidth, int scaledHeight, boolean preserveAlpha)
{
return getResizedCopyOfImage(image, scaledWidth, scaledHeight, preserveAlpha);
}
public byte[] getByte()
{
return getByteOfImage(image);
}
public ImageIcon getImageIcon()
{
return new ImageIcon(image);
}
public BufferedImage getCropedImage(int x, int y, int width, int height)
{
return getCropedImageOfImage(image, x, y, width, height);
}
public BufferedImage getCropedImageFromCenter(Dimension panelDimension,int clipedWidth, int clipedHeight)
{
return getCropedImageOfImageFromCenter(image, panelDimension, clipedWidth, clipedHeight);
}
public BufferedImage getResizedCopyOfImage(BufferedImage originalImage,int scaledWidth, int scaledHeight, boolean preserveAlpha)
{
int imageType = preserveAlpha ? BufferedImage.TYPE_INT_RGB : BufferedImage.TYPE_INT_ARGB;
BufferedImage scaledBI = new BufferedImage(scaledWidth, scaledHeight, imageType);
Graphics2D g = scaledBI.createGraphics();
if (preserveAlpha)
{
g.setComposite(AlphaComposite.Src);
}
g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g.setRenderingHint(RenderingHints.KEY_RENDERING,
RenderingHints.VALUE_RENDER_QUALITY);
g.setRenderingHint(RenderingHints.KEY_ANTIALIASING,
RenderingHints.VALUE_ANTIALIAS_ON);
g.drawImage(originalImage, 0, 0, scaledWidth, scaledHeight, null);
g.dispose();
return scaledBI;
}
public byte[] getByteOfImage(BufferedImage sourceImage)
{
try
{
ByteArrayOutputStream baos = new ByteArrayOutputStream();
ImageIO.write(sourceImage, getImageExtension(), baos);
baos.flush();
byte[] imageData = baos.toByteArray();
baos.close();
return imageData;
}
catch (IOException ex)
{
Exceptions.printStackTrace(ex);
return null;
}
}
public ImageIcon getImageIconFromImage(BufferedImage sourceImage)
{
return new ImageIcon(sourceImage);
}
public BufferedImage getCropedImageOfImage(BufferedImage sourceImage, int x, int y, int width, int height)
{
return sourceImage.getSubimage(x, y, width, height);
}
public BufferedImage getCropedImageOfImageFromCenter(BufferedImage sourceImage, Dimension panelDimension,int clipedWidth, int clipedHeight)
{
Rectangle clip = new Rectangle(clipedWidth, clipedHeight);
clip.x = (panelDimension.width - clip.width) / 2;
clip.y = (panelDimension.height - clip.height) / 2;
int x0 = (panelDimension.width - sourceImage.getWidth()) / 2;
int y0 = (panelDimension.height - sourceImage.getHeight()) / 2;
int x = clip.x - x0;
int y = clip.y - y0;
return sourceImage.getSubimage(x, y, clip.width, clip.height);
}
}
