Resizing image in Java
If you have an java.awt.Image
, resizing it doesn't require any additional libraries. Just do:
Image newImage = yourImage.getScaledInstance(newWidth, newHeight, Image.SCALE_DEFAULT);
Obviously, replace newWidth
and newHeight
with the dimensions of the specified image.
Notice the last parameter: it tells the runtime the algorithm you want to use for resizing.
There are algorithms that produce a very precise result, however these take a large time to complete.
You can use any of the following algorithms:
-
Image.SCALE_DEFAULT
: Use the default image-scaling algorithm. -
Image.SCALE_FAST
: Choose an image-scaling algorithm that gives higher priority to scaling speed than smoothness of the scaled image. -
Image.SCALE_SMOOTH
: Choose an image-scaling algorithm that gives higher priority to image smoothness than scaling speed. -
Image.SCALE_AREA_AVERAGING
: Use the Area Averaging image scaling algorithm. -
Image.SCALE_REPLICATE
: Use the image scaling algorithm embodied in theReplicateScaleFilter
class.
See the Javadoc for more info.
We're doing this to create thumbnails of images:
BufferedImage tThumbImage = new BufferedImage( tThumbWidth, tThumbHeight, BufferedImage.TYPE_INT_RGB );
Graphics2D tGraphics2D = tThumbImage.createGraphics(); //create a graphics object to paint to
tGraphics2D.setBackground( Color.WHITE );
tGraphics2D.setPaint( Color.WHITE );
tGraphics2D.fillRect( 0, 0, tThumbWidth, tThumbHeight );
tGraphics2D.setRenderingHint( RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR );
tGraphics2D.drawImage( tOriginalImage, 0, 0, tThumbWidth, tThumbHeight, null ); //draw the image scaled
ImageIO.write( tThumbImage, "JPG", tThumbnailTarget ); //write the image to a file
Try this:
ImageIcon icon = new ImageIcon(UrlToPngFile);
Image scaleImage = icon.getImage().getScaledInstance(28, 28,Image.SCALE_DEFAULT);
Resize image with high quality:
private static InputStream resizeImage(InputStream uploadedInputStream, String fileName, int width, int height) {
try {
BufferedImage image = ImageIO.read(uploadedInputStream);
Image originalImage= image.getScaledInstance(width, height, Image.SCALE_DEFAULT);
int type = ((image.getType() == 0) ? BufferedImage.TYPE_INT_ARGB : image.getType());
BufferedImage resizedImage = new BufferedImage(width, height, type);
Graphics2D g2d = resizedImage.createGraphics();
g2d.drawImage(originalImage, 0, 0, width, height, null);
g2d.dispose();
g2d.setComposite(AlphaComposite.Src);
g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION,RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g2d.setRenderingHint(RenderingHints.KEY_RENDERING,RenderingHints.VALUE_RENDER_QUALITY);
g2d.setRenderingHint(RenderingHints.KEY_ANTIALIASING,RenderingHints.VALUE_ANTIALIAS_ON);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
ImageIO.write(resizedImage, fileName.split("\\.")[1], byteArrayOutputStream);
return new ByteArrayInputStream(byteArrayOutputStream.toByteArray());
} catch (IOException e) {
// Something is going wrong while resizing image
return uploadedInputStream;
}
}
int newHeight = 150;
int newWidth = 150;
holder.iv_arrow.requestLayout();
holder.iv_arrow.getLayoutParams().height = newHeight;
holder.iv_arrow.getLayoutParams().width = newWidth;
holder.iv_arrow.setScaleType(ImageView.ScaleType.FIT_XY);
holder.iv_arrow.setImageResource(R.drawable.video_menu);