3 import java.awt.Dimension;
4 import java.awt.Graphics;
5 import java.awt.Graphics2D;
7 import java.awt.image.BufferedImage;
8 import java.awt.image.ConvolveOp;
9 import java.awt.image.Kernel;
11 import javax.swing.ImageIcon;
14 * Class for providing generic image processing functions
16 public abstract class ImageUtils
18 private static final float SMOOTH_FACTOR = 0.008f;
19 private static ConvolveOp CONVOLVER = null;
21 /** Static block for initialization */
24 float[] smoothMatrix = {
26 SMOOTH_FACTOR, 1-(SMOOTH_FACTOR*4), SMOOTH_FACTOR,
29 CONVOLVER = new ConvolveOp(new Kernel(3, 3, smoothMatrix));
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
40 public static BufferedImage createScaledImage(Image inImage, int inWidth, int inHeight)
42 if (inWidth <= 0 || inHeight <= 0) {
45 // create smaller image and force its loading
46 Image smallerImage = inImage.getScaledInstance(inWidth, inHeight, Image.SCALE_SMOOTH);
47 Image tempImage = new ImageIcon(smallerImage).getImage();
48 tempImage.getWidth(null);
50 // create buffered image to do transform
51 BufferedImage buffer = new BufferedImage(inWidth, inHeight, BufferedImage.TYPE_INT_RGB);
52 // copy scaled picture into buffer
53 Graphics buffG = buffer.getGraphics();
54 buffG.drawImage(smallerImage, 0, 0, inWidth, inHeight, null);
58 smallerImage = null; tempImage = null;
59 // smooth scaled image using a normalized 3x3 matrix - taking next neighbour
60 buffer = CONVOLVER.filter(buffer, null);
67 * Work out the max size of a thumbnail
68 * @param inOrigWidth width of original picture
69 * @param inOrigHeight height of original picture
70 * @param inMaxWidth max width of thumbnail
71 * @param inMaxHeight max height of thumbnail
72 * @return size of thumbnail as Dimension
74 public static Dimension getThumbnailSize(int inOrigWidth, int inOrigHeight, int inMaxWidth, int inMaxHeight)
76 if (inMaxWidth <= 0 || inMaxHeight <= 0) {return new Dimension(1, 1);}
77 // work out maximum zoom ratio available so that thumbnail isn't too big
78 double xZoom = inMaxWidth * 1.0 / inOrigWidth;
79 double yZoom = inMaxHeight * 1.0 / inOrigHeight;
80 double zoom = (xZoom > yZoom?yZoom:xZoom);
81 // Don't make thumbnail bigger than picture
82 if (zoom > 1.0) {return new Dimension(inOrigWidth, inOrigHeight);}
84 // calculate new width and height
85 final int xSize = (int) (zoom * inOrigWidth);
86 final int ySize = (int) (zoom * inOrigHeight);
87 if (xSize <= 0 || ySize <= 0) {return new Dimension(1, 1);}
88 return new Dimension (xSize, ySize);
93 * Create a new image by rotating and scaling the given one
94 * @param inImage input image
95 * @param inMaxWidth maximum width of output image
96 * @param inMaxHeight maximum height of output image
97 * @param inRotationDegrees number of degrees to rotate clockwise (0, 90, 180 or 270)
98 * @return rotated, scaled image
100 public static BufferedImage rotateImage(Image inImage, int inMaxWidth, int inMaxHeight, int inRotationDegrees)
102 // Create scaled image of suitable size
103 boolean isRotated = (inRotationDegrees % 180 != 0);
104 int origWidth = inImage.getWidth(null);
105 int origHeight = inImage.getHeight(null);
106 int thumbWidth = isRotated?origHeight:origWidth;
107 int thumbHeight = isRotated?origWidth:origHeight;
108 Dimension scaledSize = getThumbnailSize(thumbWidth, thumbHeight, inMaxWidth, inMaxHeight);
109 BufferedImage result = new BufferedImage(scaledSize.width, scaledSize.height, BufferedImage.TYPE_INT_RGB);
110 // Do different things according to rotation angle (a bit messy, sorry!)
111 if (inRotationDegrees == 0)
113 // Not rotated, so just copy image directly
114 result.getGraphics().drawImage(inImage, 0, 0, scaledSize.width, scaledSize.height, null);
118 // Need to use Graphics2D for rotation, not Graphics
119 Graphics2D g2d = result.createGraphics();
120 switch (inRotationDegrees)
123 g2d.rotate(Math.PI / 2, 0.0, 0.0);
124 g2d.drawImage(inImage, 0, -scaledSize.width, scaledSize.height, scaledSize.width, null);
127 g2d.rotate(Math.PI, scaledSize.width/2.0, scaledSize.height/2.0);
128 g2d.drawImage(inImage, 0, 0, scaledSize.width, scaledSize.height, null);
131 g2d.rotate(Math.PI * 3/2, 0.0, 0.0);
132 g2d.drawImage(inImage, -scaledSize.height, 0, scaledSize.height, scaledSize.width, null);