diff options
Diffstat (limited to 'libjava/classpath/java/awt/image/BandCombineOp.java')
| -rw-r--r-- | libjava/classpath/java/awt/image/BandCombineOp.java | 128 |
1 files changed, 89 insertions, 39 deletions
diff --git a/libjava/classpath/java/awt/image/BandCombineOp.java b/libjava/classpath/java/awt/image/BandCombineOp.java index 634125ed23f..d9ce16fad07 100644 --- a/libjava/classpath/java/awt/image/BandCombineOp.java +++ b/libjava/classpath/java/awt/image/BandCombineOp.java @@ -1,4 +1,5 @@ -/* Copyright (C) 2004 Free Software Foundation +/* BandCombineOp.java - perform a combination on the bands of a raster + Copyright (C) 2004, 2006 Free Software Foundation This file is part of GNU Classpath. @@ -36,10 +37,10 @@ exception statement from your version. */ package java.awt.image; -import java.awt.Point; import java.awt.RenderingHints; import java.awt.geom.Point2D; import java.awt.geom.Rectangle2D; +import java.util.Arrays; /** * Filter Raster pixels by applying a matrix. @@ -53,6 +54,9 @@ import java.awt.geom.Rectangle2D; * for the destination. Therefore the destination Raster must contain the * same number of bands as the number of rows in the filter matrix. * + * This Op assumes that samples are integers; floating point sample types will + * be rounded to their nearest integer value during filtering. + * * @author Jerry Quinn (jlquinn@optonline.net) */ public class BandCombineOp implements RasterOp @@ -65,52 +69,74 @@ public class BandCombineOp implements RasterOp * * @param matrix The matrix to filter pixels with. * @param hints Rendering hints to apply. Ignored. + * @throws ArrayIndexOutOfBoundsException if the matrix is invalid */ public BandCombineOp(float[][] matrix, RenderingHints hints) { - this.matrix = matrix; + this.matrix = new float[matrix.length][]; + int width = matrix[0].length; + for (int i = 0; i < matrix.length; i++) + { + this.matrix[i] = new float[width + 1]; + for (int j = 0; j < width; j++) + this.matrix[i][j] = matrix[i][j]; + + // The reference implementation pads the array with a trailing zero... + this.matrix[i][width] = 0; + } + this.hints = hints; } /** - * Filter Raster pixels through a matrix. - * - * Applies the Op matrix to source pixes to produce dest pixels. Each row - * of the matrix is multiplied by the src pixel components to produce the - * dest pixel. If matrix is one more than the number of bands in the src, - * the last element is implicitly multiplied by 1, i.e. added to the sum - * for that dest component. - * - * If dest is null, a suitable Raster is created. This implementation uses - * createCompatibleDestRaster. + * Filter Raster pixels through a matrix. Applies the Op matrix to source + * pixes to produce dest pixels. Each row of the matrix is multiplied by the + * src pixel components to produce the dest pixel. If matrix is one more than + * the number of bands in the src, the last element is implicitly multiplied + * by 1, i.e. added to the sum for that dest component. If dest is null, a + * suitable Raster is created. This implementation uses + * createCompatibleDestRaster. * * @param src The source Raster. - * @param dest The destination Raster, or null. - * @returns The destination Raster or an allocated Raster. + * @param dest The destination Raster, or null. + * @throws IllegalArgumentException if the destination raster is incompatible + * with the source raster. + * @return The filtered Raster. * @see java.awt.image.RasterOp#filter(java.awt.image.Raster, - *java.awt.image.WritableRaster) + * java.awt.image.WritableRaster) */ public WritableRaster filter(Raster src, WritableRaster dest) { if (dest == null) dest = createCompatibleDestRaster(src); - + else if (dest.getNumBands() != src.getNumBands() + || dest.getTransferType() != src.getTransferType()) + throw new IllegalArgumentException("Destination raster is incompatible with source raster"); + // Filter the pixels - float[] spix = new float[matrix[0].length]; - float[] dpix = new float[matrix.length]; + int[] spix = new int[matrix[0].length - 1]; + int[] spix2 = new int[matrix[0].length - 1]; + int[] dpix = new int[matrix.length]; for (int y = src.getMinY(); y < src.getHeight() + src.getMinY(); y++) for (int x = src.getMinX(); x < src.getWidth() + src.getMinX(); x++) - { - // In case matrix rows have implicit translation - spix[spix.length - 1] = 1.0f; - src.getPixel(x, y, spix); - for (int i = 0; i < matrix.length; i++) { - dpix[i] = 0; - for (int j = 0; j < matrix[0].length; j++) - dpix[i] += spix[j] * matrix[i][j]; + // In case matrix rows have implicit translation + spix[spix.length - 1] = 1; + src.getPixel(x, y, spix); + + // Do not re-calculate if pixel is identical to the last one + // (ie, blocks of the same colour) + if (!Arrays.equals(spix, spix2)) + { + System.arraycopy(spix, 0, spix2, 0, spix.length); + for (int i = 0; i < matrix.length; i++) + { + dpix[i] = 0; + for (int j = 0; j < matrix[0].length - 1; j++) + dpix[i] += spix[j] * (int)matrix[i][j]; + } + } + dest.setPixel(x, y, dpix); } - dest.setPixel(x, y, dpix); - } return dest; } @@ -125,28 +151,48 @@ public class BandCombineOp implements RasterOp /** * Creates a new WritableRaster that can be used as the destination for this - * Op. This implementation creates a Banded Raster with data type FLOAT. - * @see - *java.awt.image.RasterOp#createCompatibleDestRaster(java.awt.image.Raster) + * Op. The number of bands in the source raster must equal the number of rows + * in the op matrix, which must also be equal to either the number of columns + * or (columns - 1) in the matrix. + * + * @param src The source raster. + * @return A compatible raster. + * @see java.awt.image.RasterOp#createCompatibleDestRaster(java.awt.image.Raster) + * @throws IllegalArgumentException if the raster is incompatible with the + * matrix. */ public WritableRaster createCompatibleDestRaster(Raster src) { - return Raster.createBandedRaster(DataBuffer.TYPE_FLOAT, src.getWidth(), - src.getHeight(), matrix.length, - new Point(src.getMinX(), src.getMinY())); + // Destination raster must have same number of bands as source + if (src.getNumBands() != matrix.length) + throw new IllegalArgumentException("Number of rows in matrix specifies an " + + "incompatible number of bands"); + + // We use -1 and -2 because we previously padded the rows with a trailing 0 + if (src.getNumBands() != matrix[0].length - 1 + && src.getNumBands() != matrix[0].length - 2) + throw new IllegalArgumentException("Incompatible number of bands: " + + "the number of bands in the raster must equal the number of " + + "columns in the matrix, optionally minus one"); + + return src.createCompatibleWritableRaster(); } - /** Return corresponding destination point for source point. + /** + * Return corresponding destination point for source point. Because this is + * not a geometric operation, it simply returns a copy of the source. * - * LookupOp will return the value of src unchanged. * @param src The source point. * @param dst The destination point. + * @return dst The destination point. * @see java.awt.image.RasterOp#getPoint2D(java.awt.geom.Point2D, *java.awt.geom.Point2D) */ public final Point2D getPoint2D(Point2D src, Point2D dst) { - if (dst == null) return (Point2D)src.clone(); + if (dst == null) + return (Point2D)src.clone(); + dst.setLocation(src); return dst; } @@ -159,7 +205,11 @@ public class BandCombineOp implements RasterOp return hints; } - /** Return the matrix for this Op. */ + /** + * Return the matrix used in this operation. + * + * @return The matrix used in this operation. + */ public final float[][] getMatrix() { return matrix; |
