Java image resize, maintain aspect ratio

Question

I have an image which I resize:

if((width != null) || (height != null))
{
    try{
        // scale image on disk
        BufferedImage originalImage = ImageI         


        

Answer 1

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));
}