-/* Copyright (C) 2004 Free Software Foundation
+/* Copyright (C) 2004, 2006 Free Software Foundation
This file is part of GNU Classpath.
import java.util.Arrays;
/**
+ * RescaleOp is a filter that changes each pixel by a scaling factor and offset.
+ *
+ * For filtering Rasters, either one scaling factor and offset can be specified,
+ * which will be applied to all bands; or a scaling factor and offset can be
+ * specified for each band.
+ *
+ * For BufferedImages, the scaling may apply to both color and alpha components.
+ * If only one scaling factor is provided, or if the number of factors provided
+ * equals the number of color components, the scaling is performed on all color
+ * components. Otherwise, the scaling is performed on all components including
+ * alpha. Alpha premultiplication is ignored.
+ *
+ * After filtering, if color conversion is necessary, the conversion happens,
+ * taking alpha premultiplication into account.
+ *
* @author Jerry Quinn (jlquinn@optonline.net)
+ * @author Francis Kung (fkung@redhat.com)
*/
public class RescaleOp implements BufferedImageOp, RasterOp
{
private float[] offsets;
private RenderingHints hints = null;
+ /**
+ * Create a new RescaleOp object using the given scale factors and offsets.
+ *
+ * The length of the arrays must be equal to the number of bands (or number of
+ * data or color components) of the raster/image that this Op will be used on,
+ * otherwise an IllegalArgumentException will be thrown when calling the
+ * filter method.
+ *
+ * @param scaleFactors an array of scale factors.
+ * @param offsets an array of offsets.
+ * @param hints any rendering hints to use (can be null).
+ * @throws NullPointerException if the scaleFactors or offsets array is null.
+ */
public RescaleOp(float[] scaleFactors,
float[] offsets,
RenderingHints hints)
{
- this.scale = scaleFactors;
- this.offsets = offsets;
+ int length = Math.min(scaleFactors.length, offsets.length);
+
+ scale = new float[length];
+ System.arraycopy(scaleFactors, 0, this.scale, 0, length);
+
+ this.offsets = new float[length];
+ System.arraycopy(offsets, 0, this.offsets, 0, length);
+
this.hints = hints;
}
+ /**
+ * Create a new RescaleOp object using the given scale factor and offset.
+ *
+ * The same scale factor and offset will be used on all bands/components.
+ *
+ * @param scaleFactor the scale factor to use.
+ * @param offset the offset to use.
+ * @param hints any rendering hints to use (can be null).
+ */
public RescaleOp(float scaleFactor,
float offset,
RenderingHints hints)
this.hints = hints;
}
+ /**
+ * Returns the scaling factors. This method accepts an optional array, which
+ * will be used to store the factors if not null (this avoids allocating a
+ * new array). If this array is too small to hold all the scaling factors,
+ * the array will be filled and the remaining factors discarded.
+ *
+ * @param scaleFactors array to store the scaling factors in (can be null).
+ * @return an array of scaling factors.
+ */
public final float[] getScaleFactors(float[] scaleFactors)
{
if (scaleFactors == null)
scaleFactors = new float[scale.length];
- System.arraycopy(scale, 0, scaleFactors, 0, scale.length);
+ System.arraycopy(scale, 0, scaleFactors, 0, Math.min(scale.length,
+ scaleFactors.length));
return scaleFactors;
}
+ /**
+ * Returns the offsets. This method accepts an optional array, which
+ * will be used to store the offsets if not null (this avoids allocating a
+ * new array). If this array is too small to hold all the offsets, the array
+ * will be filled and the remaining factors discarded.
+ *
+ * @param offsets array to store the offsets in (can be null).
+ * @return an array of offsets.
+ */
public final float[] getOffsets(float[] offsets)
{
if (offsets == null)
offsets = new float[this.offsets.length];
- System.arraycopy(this.offsets, 0, offsets, 0, this.offsets.length);
+ System.arraycopy(this.offsets, 0, offsets, 0, Math.min(this.offsets.length,
+ offsets.length));
return offsets;
}
+ /**
+ * Returns the number of scaling factors / offsets.
+ *
+ * @return the number of scaling factors / offsets.
+ */
public final int getNumFactors()
{
return scale.length;
return hints;
}
- /* (non-Javadoc)
- * @see java.awt.image.BufferedImageOp#filter(java.awt.image.BufferedImage, java.awt.image.BufferedImage)
+ /**
+ * Converts the source image using the scale factors and offsets specified in
+ * the constructor. The resulting image is stored in the destination image if
+ * one is provided; otherwise a new BufferedImage is created and returned.
+ *
+ * The source image cannot use an IndexColorModel, and the destination image
+ * (if one is provided) must have the same size.
+ *
+ * If the final value of a sample is beyond the range of the color model, it
+ * will be clipped to the appropriate maximum / minimum.
+ *
+ * @param src The source image.
+ * @param dst The destination image.
+ * @throws IllegalArgumentException if the rasters and/or color spaces are
+ * incompatible.
+ * @return The rescaled image.
*/
public final BufferedImage filter(BufferedImage src, BufferedImage dst)
{
- // TODO Make sure premultiplied alpha is handled correctly.
- // TODO See that color conversion is handled.
- // TODO figure out how to use rendering hints.
- if (scale.length != offsets.length)
- throw new IllegalArgumentException();
+ // Initial checks
+ if (scale.length != 1
+ && scale.length != src.getColorModel().getNumComponents()
+ && (scale.length != src.getColorModel().getNumColorComponents()))
+ throw new IllegalArgumentException("Source image has wrong number of "
+ + "bands for these scaling factors.");
- ColorModel scm = src.getColorModel();
- if (dst == null) dst = createCompatibleDestImage(src, null);
+ if (dst == null)
+ dst = createCompatibleDestImage(src, null);
+ else if (src.getHeight() != dst.getHeight()
+ || src.getWidth() != dst.getWidth())
+ throw new IllegalArgumentException("Source and destination images are "
+ + "different sizes.");
- WritableRaster wsrc = src.getRaster();
- WritableRaster wdst = dst.getRaster();
-
- // Share constant across colors except alpha
- if (scale.length == 1 || scale.length == scm.getNumColorComponents())
+ // Prepare for possible colorspace conversion
+ BufferedImage dst2 = dst;
+ if (dst.getColorModel().getColorSpace().getType() != src.getColorModel().getColorSpace().getType())
+ dst2 = createCompatibleDestImage(src, src.getColorModel());
+
+ // Figure out how many bands to scale
+ int numBands = scale.length;
+ if (scale.length == 1)
+ numBands = src.getColorModel().getNumColorComponents();
+ boolean[] bands = new boolean[numBands];
+ // this assumes the alpha, if present, is the last band
+ Arrays.fill(bands, true);
+
+ // Perform rescaling
+ filter(src.getRaster(), dst2.getRaster(), bands);
+
+ // Copy alpha band if needed (ie if it exists and wasn't scaled)
+ // NOTE: This assumes the alpha component is the last band!
+ if (src.getColorModel().hasAlpha()
+ && numBands == src.getColorModel().getNumColorComponents())
{
- // Construct a raster that doesn't include an alpha band.
- int[] subbands = new int[scm.getNumColorComponents()];
- for (int i=0; i < subbands.length; i++) subbands[i] = i;
- wsrc =
- wsrc.createWritableChild(wsrc.minX, wsrc.minY, wsrc.width, wsrc.height,
- wsrc.minX, wsrc.minY, subbands);
+
+ dst2.getRaster().setSamples(0, 0, src.getWidth(), src.getHeight(),
+ numBands,
+ src.getRaster().getSamples(0, 0,
+ src.getWidth(),
+ src.getHeight(),
+ numBands,
+ (int[]) null));
}
- // else all color bands
- filter(wsrc, wdst);
+ // Perform colorspace conversion if needed
+ if (dst != dst2)
+ new ColorConvertOp(hints).filter(dst2, dst);
+
return dst;
}
*/
public final WritableRaster filter(Raster src, WritableRaster dest)
{
- if (dest == null) dest = src.createCompatibleWritableRaster();
-
// Required sanity checks
- if (src.numBands != dest.numBands || scale.length != offsets.length)
- throw new IllegalArgumentException();
if (scale.length != 1 && scale.length != src.numBands)
- throw new IllegalArgumentException();
+ throw new IllegalArgumentException("Number of rasters is incompatible "
+ + "with the number of scaling "
+ + "factors provided.");
- // Create scaling arrays if needed
- float[] lscale = scale;
- float[] loff = offsets;
- if (scale.length == 1)
- {
- lscale = new float[src.numBands];
- Arrays.fill(lscale, scale[0]);
- loff = new float[src.numBands];
- Arrays.fill(loff, offsets[0]);
- }
+ if (dest == null)
+ dest = src.createCompatibleWritableRaster();
+ else if (src.getHeight() != dest.getHeight()
+ || src.getWidth() != dest.getWidth())
+ throw new IllegalArgumentException("Source and destination rasters are "
+ + "different sizes.");
+ else if (src.numBands != dest.numBands)
+ throw new IllegalArgumentException("Source and destination rasters "
+ + "are incompatible.");
+
+ // Filter all bands
+ boolean[] bands = new boolean[src.getNumBands()];
+ Arrays.fill(bands, true);
+ return filter(src, dest, bands);
+ }
+
+ /**
+ * Perform raster-based filtering on a selected number of bands.
+ *
+ * The length of the bands array should equal the number of bands; a true
+ * element indicates filtering should happen on the corresponding band, while
+ * a false element will skip the band.
+ *
+ * The rasters are assumed to be compatible and non-null.
+ *
+ * @param src the source raster.
+ * @param dest the destination raster.
+ * @param bands an array indicating which bands to filter.
+ * @throws NullPointerException if any parameter is null.
+ * @throws ArrayIndexOutOfBoundsException if the bands array is too small.
+ * @return the destination raster.
+ */
+ private WritableRaster filter(Raster src, WritableRaster dest, boolean[] bands)
+ {
+ int[] values = new int[src.getHeight() * src.getWidth()];
+ float scaleFactor, offset;
+
+ // Find max sample value, to be used for clipping later
+ int[] maxValue = src.getSampleModel().getSampleSize();
+ for (int i = 0; i < maxValue.length; i++)
+ maxValue[i] = (int)Math.pow(2, maxValue[i]) - 1;
+
+ // TODO: can this be optimized further?
+ // Filter all samples of all requested bands
+ for (int band = 0; band < bands.length; band++)
+ if (bands[band])
+ {
+ values = src.getSamples(src.getMinX(), src.getMinY(), src.getWidth(),
+ src.getHeight(), band, values);
- // TODO The efficiency here can be improved for various data storage
- // patterns, aka SampleModels.
- float[] pixel = new float[src.numBands];
- for (int y = src.minY; y < src.height + src.minY; y++)
- for (int x = src.minX; x < src.width + src.minX; x++)
- {
- src.getPixel(x, y, pixel);
- for (int b = 0; b < src.numBands; b++)
- pixel[b] = pixel[b] * lscale[b] + loff[b];
- dest.setPixel(x, y, pixel);
- }
+ if (scale.length == 1)
+ {
+ scaleFactor = scale[0];
+ offset = offsets[0];
+ }
+ else
+ {
+ scaleFactor = scale[band];
+ offset = offsets[band];
+ }
+
+ for (int i = 0; i < values.length; i++)
+ {
+ values[i] = (int) (values[i] * scaleFactor + offset);
+
+ // Clip if needed
+ if (values[i] < 0)
+ values[i] = 0;
+ if (values[i] > maxValue[band])
+ values[i] = maxValue[band];
+ }
+
+ dest.setSamples(dest.getMinX(), dest.getMinY(), dest.getWidth(),
+ dest.getHeight(), band, values);
+ }
+
return dest;
}
- /* (non-Javadoc)
- * @see java.awt.image.BufferedImageOp#createCompatibleDestImage(java.awt.image.BufferedImage, java.awt.image.ColorModel)
+ /*
+ * (non-Javadoc)
+ *
+ * @see java.awt.image.BufferedImageOp#createCompatibleDestImage(java.awt.image.BufferedImage,
+ * java.awt.image.ColorModel)
*/
public BufferedImage createCompatibleDestImage(BufferedImage src,
ColorModel dstCM)
{
- if (dstCM == null) dstCM = src.getColorModel();
- WritableRaster wr = src.getRaster().createCompatibleWritableRaster();
- BufferedImage image
- = new BufferedImage(dstCM, wr, src.isPremultiplied, null);
- return image;
+ if (dstCM == null)
+ return new BufferedImage(src.getWidth(), src.getHeight(), src.getType());
+
+ return new BufferedImage(dstCM,
+ src.getRaster().createCompatibleWritableRaster(),
+ src.isAlphaPremultiplied(), null);
}
/* (non-Javadoc)
/* (non-Javadoc)
* @see java.awt.image.BufferedImageOp#getPoint2D(java.awt.geom.Point2D, java.awt.geom.Point2D)
*/
- public final Point2D getPoint2D(Point2D src, Point2D dst) {
- if (dst == null) dst = (Point2D) src.clone();
- else dst.setLocation(src);
+ public final Point2D getPoint2D(Point2D src, Point2D dst)
+ {
+ if (dst == null)
+ dst = (Point2D) src.clone();
+ else
+ dst.setLocation(src);
+
return dst;
}
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