tim/prune/gui/ImageUtils.java

   1 package tim.prune.gui;
   2
   3 import java.awt.Dimension;
   4 import java.awt.Graphics;
   5 import java.awt.Graphics2D;
   6 import java.awt.Image;
   7 import java.awt.image.BufferedImage;
   8 import java.awt.image.ConvolveOp;
   9 import java.awt.image.Kernel;
  10
  11 import javax.swing.ImageIcon;
  12
  13 /**
  14  * Class for providing generic image processing functions
  15  */
  16 public abstract class ImageUtils
  17 {
  18         private static final float SMOOTH_FACTOR = 0.008f;
  19         private static ConvolveOp CONVOLVER = null;
  20
  21         /** Static block for initialization */
  22         static
  23         {
  24                 float[] smoothMatrix = {
  25                         0, SMOOTH_FACTOR, 0,
  26                         SMOOTH_FACTOR, 1-(SMOOTH_FACTOR*4), SMOOTH_FACTOR,
  27                         0, SMOOTH_FACTOR, 0
  28                 };
  29                 CONVOLVER = new ConvolveOp(new Kernel(3, 3, smoothMatrix));
  30         }
  31
  32
  33         /**
  34          * Create a scaled and smoothed image according to the specified size
  35          * @param inImage image to scale
  36          * @param inWidth width to scale to
  37          * @param inHeight height to scale to
  38          * @return BufferedImage containing scaled result
  39          */
  40         public static BufferedImage createScaledImage(Image inImage, int inWidth, int inHeight)
  41         {
  42                 // create smaller image and force its loading
  43                 Image smallerImage = inImage.getScaledInstance(inWidth, inHeight, Image.SCALE_SMOOTH);
  44                 Image tempImage = new ImageIcon(smallerImage).getImage();
  45                 tempImage.getWidth(null);
  46
  47                 // create buffered image to do transform
  48                 BufferedImage buffer = new BufferedImage(inWidth, inHeight, BufferedImage.TYPE_INT_RGB);
  49                 // copy scaled picture into buffer
  50                 Graphics buffG = buffer.getGraphics();
  51                 buffG.drawImage(smallerImage, 0, 0, inWidth, inHeight, null);
  52                 buffG.dispose();
  53
  54                 // clear variables
  55                 smallerImage = null; tempImage = null;
  56                 // smooth scaled image using a normalized 3x3 matrix - taking next neighbour
  57                 buffer = CONVOLVER.filter(buffer, null);
  58
  59                 return buffer;
  60         }
  61
  62
  63         /**
  64          * Work out the max size of a thumbnail
  65          * @param inOrigWidth width of original picture
  66          * @param inOrigHeight height of original picture
  67          * @param inMaxWidth max width of thumbnail
  68          * @param inMaxHeight max height of thumbnail
  69          * @return size of thumbnail as Dimension
  70          */
  71         public static Dimension getThumbnailSize(int inOrigWidth, int inOrigHeight, int inMaxWidth, int inMaxHeight)
  72         {
  73                 assert(inMaxWidth > 0 && inMaxHeight > 0);
  74                 // work out maximum zoom ratio available so that thumbnail isn't too big
  75                 double xZoom = inMaxWidth * 1.0 / inOrigWidth;
  76                 double yZoom = inMaxHeight * 1.0 / inOrigHeight;
  77                 double zoom = (xZoom > yZoom?yZoom:xZoom);
  78                 // Don't make thumbnail bigger than picture
  79                 if (zoom > 1.0) {return new Dimension(inOrigWidth, inOrigHeight);}
  80                 // calculate new width and height
  81                 return new Dimension ((int) (zoom * inOrigWidth), (int) (zoom * inOrigHeight));
  82         }
  83
  84
  85         /**
  86          * Create a new image by rotating and scaling the given one
  87          * @param inImage input image
  88          * @param inMaxWidth maximum width of output image
  89          * @param inMaxHeight maximum height of output image
  90          * @param inRotationDegrees number of degrees to rotate clockwise (0, 90, 180 or 270)
  91          * @return rotated, scaled image
  92          */
  93         public static BufferedImage rotateImage(Image inImage, int inMaxWidth, int inMaxHeight, int inRotationDegrees)
  94         {
  95                 // Create scaled image of suitable size
  96                 boolean isRotated = (inRotationDegrees % 180 != 0);
  97                 int origWidth = inImage.getWidth(null);
  98                 int origHeight = inImage.getHeight(null);
  99                 int thumbWidth = isRotated?origHeight:origWidth;
 100                 int thumbHeight = isRotated?origWidth:origHeight;
 101                 Dimension scaledSize = getThumbnailSize(thumbWidth, thumbHeight, inMaxWidth, inMaxHeight);
 102                 BufferedImage result = new BufferedImage(scaledSize.width, scaledSize.height, BufferedImage.TYPE_INT_RGB);
 103                 // Do different things according to rotation angle (a bit messy, sorry!)
 104                 if (inRotationDegrees == 0)
 105                 {
 106                         // Not rotated, so just copy image directly
 107                         result.getGraphics().drawImage(inImage, 0, 0, scaledSize.width, scaledSize.height, null);
 108                 }
 109                 else
 110                 {
 111                         // Need to use Graphics2D for rotation, not Graphics
 112                         Graphics2D g2d = result.createGraphics();
 113                         switch (inRotationDegrees)
 114                         {
 115                                 case 90:
 116                                         g2d.rotate(Math.PI / 2, 0.0, 0.0);
 117                                         g2d.drawImage(inImage, 0, -scaledSize.width, scaledSize.height, scaledSize.width, null);
 118                                         break;
 119                                 case 180:
 120                                         g2d.rotate(Math.PI, scaledSize.width/2.0, scaledSize.height/2.0);
 121                                         g2d.drawImage(inImage, 0, 0, scaledSize.width, scaledSize.height, null);
 122                                         break;
 123                                 case 270:
 124                                         g2d.rotate(Math.PI * 3/2, 0.0, 0.0);
 125                                         g2d.drawImage(inImage, -scaledSize.height, 0, scaledSize.height, scaledSize.width, null);
 126                         }
 127                         // Clear up memory
 128                         g2d.dispose();
 129                 }
 130                 return result;
 131         }
 132 }