问题
I am trying to resized a bufferedimage. I am able to store it and show up on a jframe no problems but I can't seem to resize it. Any tips on how I can change this to make it work and show the image as a 200*200 file would be great
private void profPic(){
String path = factory.getString("bottle");
BufferedImage img = ImageIO.read(new File(path));
}
public static BufferedImage resize(BufferedImage img, int newW, int newH) {
int w = img.getWidth();
int h = img.getHeight();
BufferedImage dimg = new BufferedImage(newW, newH, img.getType());
Graphics2D g = dimg.createGraphics();
g.setRenderingHint(RenderingHints.KEY_INTERPOLATION,
RenderingHints.VALUE_INTERPOLATION_BILINEAR);
g.drawImage(img, 0, 0, newW, newH, 0, 0, w, h, null);
g.dispose();
return dimg;
}
回答1:
Updated answer
I cannot recall why my original answer worked but having tested it in a separate environment, I agree, the original accepted answer doesn't work (why I said it did I cannot remember either). This, on the other hand, did work:
public static BufferedImage resize(BufferedImage img, int newW, int newH) {
Image tmp = img.getScaledInstance(newW, newH, Image.SCALE_SMOOTH);
BufferedImage dimg = new BufferedImage(newW, newH, BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = dimg.createGraphics();
g2d.drawImage(tmp, 0, 0, null);
g2d.dispose();
return dimg;
}
回答2:
If all that is required is to resize a BufferedImage in the resize method, then the Thumbnailator library can do that fairly easily:
public static BufferedImage resize(BufferedImage img, int newW, int newH) {
return Thumbnails.of(img).size(newW, newH).asBufferedImage();
}
The above code will resize the img to fit the dimensions of newW and newH while maintaining the aspect ratio of the original image.
If maintaining the aspect ratio is not required and resizing to exactly the given dimensions is required, then the forceSize method can be used in place of the size method:
public static BufferedImage resize(BufferedImage img, int newW, int newH) {
return Thumbnails.of(img).forceSize(newW, newH).asBufferedImage();
}
Using the Image.getScaledInstance method will not guarantee that the aspect ratio of the original image will be maintained for the resized image, and furthermore, it is in general very slow.
Thumbnailator uses a technique to progressively resize the image which can be several times faster than Image.getScaledInstance while achieving an image quality which generally is comparable.
Disclaimer: I am the maintainer of this library.
回答3:
try the imgscalr library. Best lib i found- very fast, good quality and simple to use
BufferedImage thumbnail = Scalr.resize(image, 150);
http://www.thebuzzmedia.com/software/imgscalr-java-image-scaling-library/
Apache 2 License
回答4:
This class resize from a file and get the format name:
import java.awt.Image;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.Iterator;
import javax.imageio.ImageIO;
import javax.imageio.ImageReader;
import javax.imageio.ImageWriter;
import javax.imageio.stream.ImageInputStream;
import org.apache.commons.io.IOUtils;
public class ImageResizer {
public static void main(String as[]) throws IOException{
File f = new File("C:/Users/samsungrob/Desktop/shuttle.jpg");
byte[] ba = resize(f, 600, 600);
IOUtils.write(ba, new FileOutputStream( new File("C:/Users/samsungrob/Desktop/shuttle_resized.jpg") ) );
}
public static byte[] resize(File file,
int maxWidth, int maxHeight) throws IOException{
int scaledWidth = 0, scaledHeight = 0;
BufferedImage img = ImageIO.read((ImageInputStream) file );
scaledWidth = maxWidth;
scaledHeight = (int) (img.getHeight() * ( (double) scaledWidth / img.getWidth() ));
if (scaledHeight> maxHeight) {
scaledHeight = maxHeight;
scaledWidth= (int) (img.getWidth() * ( (double) scaledHeight/ img.getHeight() ));
if (scaledWidth > maxWidth) {
scaledWidth = maxWidth;
scaledHeight = maxHeight;
}
}
Image resized = img.getScaledInstance( scaledWidth, scaledHeight, Image.SCALE_SMOOTH);
BufferedImage buffered = new BufferedImage(scaledWidth, scaledHeight, Image.SCALE_REPLICATE);
buffered.getGraphics().drawImage(resized, 0, 0 , null);
String formatName = getFormatName( file ) ;
ByteArrayOutputStream out = new ByteArrayOutputStream();
ImageIO.write(buffered,
formatName,
out);
return out.toByteArray();
}
private static String getFormatName(ImageInputStream iis) {
try {
// Find all image readers that recognize the image format
Iterator iter = ImageIO.getImageReaders(iis);
if (!iter.hasNext()) {
// No readers found
return null;
}
// Use the first reader
ImageReader reader = (ImageReader)iter.next();
// Close stream
iis.close();
// Return the format name
return reader.getFormatName();
} catch (IOException e) {
}
return null;
}
private static String getFormatName(File file) throws IOException {
return getFormatName( ImageIO.createImageInputStream(file) );
}
private static String getFormatName(InputStream is) throws IOException {
return getFormatName( ImageIO.createImageInputStream(is) );
}
}
回答5:
Here's some code that I have used to resize bufferedimages, no frills, pretty quick:
public static BufferedImage scale(BufferedImage src, int w, int h)
{
BufferedImage img =
new BufferedImage(w, h, BufferedImage.TYPE_INT_RGB);
int x, y;
int ww = src.getWidth();
int hh = src.getHeight();
int[] ys = new int[h];
for (y = 0; y < h; y++)
ys[y] = y * hh / h;
for (x = 0; x < w; x++) {
int newX = x * ww / w;
for (y = 0; y < h; y++) {
int col = src.getRGB(newX, ys[y]);
img.setRGB(x, y, col);
}
}
return img;
}
回答6:
This is a shortened version of what is actually happening in imgscalr, if you just want to use the "balanced" smoothing:
/**
* Takes a BufferedImage and resizes it according to the provided targetSize
*
* @param src the source BufferedImage
* @param targetSize maximum height (if portrait) or width (if landscape)
* @return a resized version of the provided BufferedImage
*/
private BufferedImage resize(BufferedImage src, int targetSize) {
if (targetSize <= 0) {
return src; //this can't be resized
}
int targetWidth = targetSize;
int targetHeight = targetSize;
float ratio = ((float) src.getHeight() / (float) src.getWidth());
if (ratio <= 1) { //square or landscape-oriented image
targetHeight = (int) Math.ceil((float) targetWidth * ratio);
} else { //portrait image
targetWidth = Math.round((float) targetHeight / ratio);
}
BufferedImage bi = new BufferedImage(targetWidth, targetHeight, src.getTransparency() == Transparency.OPAQUE ? BufferedImage.TYPE_INT_RGB : BufferedImage.TYPE_INT_ARGB);
Graphics2D g2d = bi.createGraphics();
g2d.setRenderingHint(RenderingHints.KEY_INTERPOLATION, RenderingHints.VALUE_INTERPOLATION_BILINEAR); //produces a balanced resizing (fast and decent quality)
g2d.drawImage(src, 0, 0, targetWidth, targetHeight, null);
g2d.dispose();
return bi;
}
回答7:
Check this out, it helps:
BufferedImage bImage = ImageIO.read(new File(C:\image.jpg);
BufferedImage thumbnail = Scalr.resize(bImage, Scalr.Method.SPEED, Scalr.Mode.FIT_TO_WIDTH,
750, 150, Scalr.OP_ANTIALIAS);
来源：https://stackoverflow.com/questions/9417356/bufferedimage-resize