Java Programming: zooming changes the color..

• olzen / 300 / Fri, 03 Jul 2009 09:52:00 GMT / Comments (4)
• When I use this code to scale bufferedImages of TYPE_USHORT_GRAY or TYPE_BYTE_GRAY, the image returned is brighter than the one passed to the method?
  Does anyone have any idea of what I am doing wrong here?
  Thanx in advance.
  
  public BufferedImage scale_ (BufferedImage img, double magFactor)
  {
  int imgWidth = (int) (img.getWidth()* magFactor);
  int imgheight = (int) (img.getHeight() * magFactor);
  displayImage = new BufferedImage ( imgWidth, imgheight, img.getType() );
  Graphics2D g = (Graphics2D) displayImage.getGraphics();
  g.drawImage( img, 0, 0, imgWidth, imgheight, null);
  return displayImage;
  }
• Keywords:

  zooming, changes, color, java, programming

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• 1. I would be interested to see what the result would be if you used a color gradation panel with blocks of graduated shades of grey.

     One possible answer is that as it expands the image it is dithering (or anti-aliasing) the image which is causing the effect you're noticing.

     No idea off hand how to prove that, or how to prevent it, but those were the thoughts I had when reading your question.

     puckstopper31 | Fri, 29 Jun 2007 10:41:00 GMT |

  2. Is it really, of does it just appear to be because the scaling is causing doubling of pixels, thus giving an appearance of a brighter image... Presumably, it would appear brigher when larger, darker when smaller.... Just a guess, though.

     bsampieri | Fri, 29 Jun 2007 10:41:00 GMT |

  3. >Presumably, it would appear brigher when larger, darker when smaller.Nope it is gettiging brighter for both larger and smaler images. but thanx for the suggestion.

     olzen | Fri, 29 Jun 2007 10:41:00 GMT |

  4. Problem solved. This occur in java 1.3.0, java 1.4.X solves this problem.Thanks for the suggestions both of you!Olzen

     olzen | Fri, 29 Jun 2007 10:41:00 GMT |