CODEWITHSUNDEEP
javaimagerescale
Fofole
Fofole

Reputation: 3548

Resize image, maintain aspect ratio

I have an image which I resize:

if((width != null) || (height != null))
{
    try{
        // Scale image on disk
        BufferedImage originalImage = ImageIO.read(file);
        int type = originalImage.getType() == 0 ? BufferedImage.TYPE_INT_ARGB
                                                : originalImage.getType();

        BufferedImage resizedImageJpg = resizeImage(originalImage, type, 200, 200);
        ImageIO.write(resizedImageJpg, "jpg", file); 

       } catch(IOException e) {
           System.out.println(e.getMessage());
       }
}

This is how I resize the image:

private static BufferedImage resizeImage(BufferedImage originalImage, int type,
                                         Integer imgWidth, Integer imgHeight)
{
    var resizedImage = new BufferedImage(imgWidth, imgHeight, type);
    Graphics2D g = resizedImage.createGraphics();
    g.drawImage(originalImage, 0, 0, imgWidth, imgHeight, null);
    g.dispose();

    return resizedImage;
}

Now the problem is, I also need to maintain aspect ratio. That is, I need the new 200/200 image to contain the new image scaled. Something like this: enter image description here

I tried some things but they didn't work out as expected. Any help is appreciated.

Upvotes: 77

Views: 134463

Answers (11)

Ozzy
Ozzy

Reputation: 8312

Here we go:

Dimension imgSize = new Dimension(500, 100);
Dimension boundary = new Dimension(200, 200);

Function to return the new size depending on the boundary:

public static Dimension getScaledDimension(Dimension imgSize, Dimension boundary) {

    int original_width = imgSize.width;
    int original_height = imgSize.height;
    int bound_width = boundary.width;
    int bound_height = boundary.height;
    int new_width = original_width;
    int new_height = original_height;

    // first check if we need to scale width
    if (original_width > bound_width) {
        //scale width to fit
        new_width = bound_width;
        //scale height to maintain aspect ratio
        new_height = (new_width * original_height) / original_width;
    }

    // then check if we need to scale even with the new height
    if (new_height > bound_height) {
        //scale height to fit instead
        new_height = bound_height;
        //scale width to maintain aspect ratio
        new_width = (new_height * original_width) / original_height;
    }

    return new Dimension(new_width, new_height);
}

In case anyone also needs the image resizing code, here is a decent solution.

If you're unsure about the above solution, there are different ways to achieve the same result.

Upvotes: 118

Matthias Braun
Matthias Braun

Reputation: 34303

Translated from here:

Dimension getScaledDimension(Dimension imageSize, Dimension boundary) {

    double widthRatio = boundary.getWidth() / imageSize.getWidth();
    double heightRatio = boundary.getHeight() / imageSize.getHeight();
    double ratio = Math.min(widthRatio, heightRatio);

    return new Dimension((int) (imageSize.width  * ratio),
                         (int) (imageSize.height * ratio));
}

You can also use imgscalr to resize images while maintaining aspect ratio:

BufferedImage resizeMe = ImageIO.read(new File("orig.jpg"));
Dimension newMaxSize = new Dimension(255, 255);
BufferedImage resizedImg = Scalr.resize(resizeMe, Method.QUALITY,
                                        newMaxSize.width, newMaxSize.height);

Upvotes: 33

satan97
satan97

Reputation: 21

Here's a small piece of code that I wrote, it resizes the image to fit the container while keeping the image's original aspect ratio. It takes in as parameters the container's width, height and the image. You can modify it to fit your needs. It's simple and works fine for my applications.

private Image scaleimage(int wid, int hei, BufferedImage img){
    Image im = img;
    double scale;
    double imw = img.getWidth();
    double imh = img.getHeight();
    if (wid > imw && hei > imh){
        im = img;
    }else if(wid/imw < hei/imh){
        scale = wid/imw;
        im = img.getScaledInstance((int) (scale*imw), (int) (scale*imh), Image.SCALE_SMOOTH);
    }else if (wid/imw > hei/imh){
        scale = hei/imh;
        im = img.getScaledInstance((int) (scale*imw), (int) (scale*imh), Image.SCALE_SMOOTH);
    }else if (wid/imw == hei/imh){
        scale = wid/imw;
        im = img.getScaledInstance((int) (scale*imw), (int) (scale*imh), Image.SCALE_SMOOTH);
    } 
    return im;
}

Upvotes: 2

Ohad Navon
Ohad Navon

Reputation: 1743

I have found the selected answer to have problems with upscaling, and so I have made (yet) another version (which I have tested):

public static Point scaleFit(Point src, Point bounds) {
  int newWidth = src.x;
  int newHeight = src.y;
  double boundsAspectRatio = bounds.y / (double) bounds.x;
  double srcAspectRatio = src.y / (double) src.x;

  // first check if we need to scale width
  if (boundsAspectRatio < srcAspectRatio) {
    // scale width to fit
    newWidth = bounds.x;
    //scale height to maintain aspect ratio
    newHeight = (newWidth * src.y) / src.x;
  } else {
    //scale height to fit instead
    newHeight = bounds.y;
    //scale width to maintain aspect ratio
    newWidth = (newHeight * src.x) / src.y;
  }

  return new Point(newWidth, newHeight);
}

Written in Android terminology :-)

as for the tests:

@Test public void scaleFit() throws Exception {
  final Point displaySize = new Point(1080, 1920);
  assertEquals(displaySize, Util.scaleFit(displaySize, displaySize));
  assertEquals(displaySize, Util.scaleFit(new Point(displaySize.x / 2, displaySize.y / 2), displaySize));
  assertEquals(displaySize, Util.scaleFit(new Point(displaySize.x * 2, displaySize.y * 2), displaySize));
  assertEquals(new Point(displaySize.x, displaySize.y * 2), Util.scaleFit(new Point(displaySize.x / 2, displaySize.y), displaySize));
  assertEquals(new Point(displaySize.x * 2, displaySize.y), Util.scaleFit(new Point(displaySize.x, displaySize.y / 2), displaySize));
  assertEquals(new Point(displaySize.x, displaySize.y * 3 / 2), Util.scaleFit(new Point(displaySize.x / 3, displaySize.y / 2), displaySize));
}

Upvotes: 0

Justinas Jakavonis
Justinas Jakavonis

Reputation: 8798

Load image:

BufferedImage bufferedImage = ImageIO.read(file);

Resize it:

private BufferedImage resizeAndCrop(BufferedImage bufferedImage, Integer width, Integer height) {

    Mode mode = (double) width / (double) height >= (double) bufferedImage.getWidth() / (double) bufferedImage.getHeight() ? Scalr.Mode.FIT_TO_WIDTH
            : Scalr.Mode.FIT_TO_HEIGHT;

    bufferedImage = Scalr.resize(bufferedImage, Scalr.Method.ULTRA_QUALITY, mode, width, height);

    int x = 0;
    int y = 0;

    if (mode == Scalr.Mode.FIT_TO_WIDTH) {
        y = (bufferedImage.getHeight() - height) / 2;
    } else if (mode == Scalr.Mode.FIT_TO_HEIGHT) {
        x = (bufferedImage.getWidth() - width) / 2;
    }

    bufferedImage = Scalr.crop(bufferedImage, x, y, width, height);

    return bufferedImage;
}

Using Scalr library:

<dependency>
    <groupId>org.imgscalr</groupId>
    <artifactId>imgscalr-lib</artifactId>
    <version>4.2</version>
</dependency>

Upvotes: 2

Gabriel Archanjo
Gabriel Archanjo

Reputation: 4597

All other answers show how to calculate the new image height in function of the new image width or vice-versa and how to resize the image using Java Image API. For those people who are looking for a straightforward solution I recommend any java image processing framework that can do this in a single line.

The exemple below uses Marvin Framework:

// 300 is the new width. The height is calculated to maintain aspect.
scale(image.clone(), image, 300);

Necessary import:

import static marvin.MarvinPluginCollection.*

Upvotes: 0

Khadzko Aliaksander
Khadzko Aliaksander

Reputation: 11

This is my solution:

/*
Change dimension of Image
*/
public static Image resizeImage(Image image, int scaledWidth, int scaledHeight, boolean preserveRatio) {  

    if (preserveRatio) { 
        double imageHeight = image.getHeight();
        double imageWidth = image.getWidth();

        if (imageHeight/scaledHeight > imageWidth/scaledWidth) {
            scaledWidth = (int) (scaledHeight * imageWidth / imageHeight);
        } else {
            scaledHeight = (int) (scaledWidth * imageHeight / imageWidth);
        }        
    }                   
    BufferedImage inputBufImage = SwingFXUtils.fromFXImage(image, null);     
    // creates output image
    BufferedImage outputBufImage = new BufferedImage(scaledWidth, scaledHeight, inputBufImage.getType());       
    // scales the input image to the output image
    Graphics2D g2d = outputBufImage.createGraphics();
    g2d.drawImage(inputBufImage, 0, 0, scaledWidth, scaledHeight, null);
    g2d.dispose();      
    return SwingFXUtils.toFXImage(outputBufImage, null);
}

Upvotes: 1

Michael
Michael

Reputation: 1

Just add one more block to Ozzy's code so the thing looks like this:

public static Dimension getScaledDimension(Dimension imgSize,Dimension boundary) {

    int original_width = imgSize.width;
    int original_height = imgSize.height;
    int bound_width = boundary.width;
    int bound_height = boundary.height;
    int new_width = original_width;
    int new_height = original_height;

    // first check if we need to scale width
    if (original_width > bound_width) {
        //scale width to fit
        new_width = bound_width;
        //scale height to maintain aspect ratio
        new_height = (new_width * original_height) / original_width;
    }

    // then check if we need to scale even with the new height
    if (new_height > bound_height) {
        //scale height to fit instead
        new_height = bound_height;
        //scale width to maintain aspect ratio
        new_width = (new_height * original_width) / original_height;
    }
    // upscale if original is smaller
    if (original_width < bound_width) {
        //scale width to fit
        new_width = bound_width;
        //scale height to maintain aspect ratio
        new_height = (new_width * original_height) / original_width;
    }

    return new Dimension(new_width, new_height);
}

Upvotes: -3

Hansj&#246;rg Hofer
Hansj&#246;rg Hofer

Reputation: 539

public class ImageTransformation {

public static final String PNG = "png";

public static byte[] resize(FileItem fileItem, int width, int height) {

    try {
        ResampleOp resampleOp = new ResampleOp(width, height);
        BufferedImage scaledImage = resampleOp.filter(ImageIO.read(fileItem.getInputStream()), null);

        ByteArrayOutputStream baos = new ByteArrayOutputStream();
        ImageIO.write(scaledImage, PNG, baos);

        return baos.toByteArray();
    } catch (Exception ex) {
        throw new MapsException("An error occured during image resizing.", ex);
    }

}

public static byte[] resizeAdjustMax(FileItem fileItem, int maxWidth, int maxHeight) {

    try {
        BufferedInputStream bis = new BufferedInputStream(fileItem.getInputStream());  
        BufferedImage bufimg = ImageIO.read(bis);   

        //check size of image 
        int img_width = bufimg.getWidth();
        int img_height = bufimg.getHeight();
        if(img_width > maxWidth || img_height > maxHeight) {
            float factx = (float) img_width / maxWidth;
            float facty = (float) img_height / maxHeight;
            float fact = (factx>facty) ? factx : facty;
            img_width = (int) ((int) img_width / fact);
            img_height = (int) ((int) img_height / fact);
        }

        return resize(fileItem,img_width, img_height);

    } catch (Exception ex) {
        throw new MapsException("An error occured during image resizing.", ex);
    }

}

}

Upvotes: 1

Pedro
Pedro

Reputation: 11

try this

float rateX =  (float)jpDisplayImagen.getWidth()/(float)img.getWidth();
float rateY = (float)jpDisplayImagen.getHeight()/(float)img.getHeight();
if (rateX>rateY){
    int W=(int)(img.getWidth()*rateY);
    int H=(int)(img.getHeight()*rateY);
    jpDisplayImagen.getGraphics().drawImage(img, 0, 0,W,H, null);
}
else{
    int W=(int)(img.getWidth()*rateX);
    int H=(int)(img.getHeight()*rateX);
    jpDisplayImagen.getGraphics().drawImage(img, 0, 0,W,H, null);
}

Upvotes: 1

daveb
daveb

Reputation: 76171

You will want to check out Image.getScaledInstance(), and more in this answer: How to improve the performance of g.drawImage() method for resizing images

Upvotes: 5

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