JDK14/Java14源码在线阅读
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* accompanied this code).
*
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package java.awt.image;
import java.awt.color.ColorSpace;
import java.awt.geom.Rectangle2D;
import java.awt.AlphaComposite;
import java.awt.Graphics2D;
import java.awt.Rectangle;
import java.awt.geom.Point2D;
import java.awt.RenderingHints;
import sun.awt.image.ImagingLib;
/**
* This class performs a pixel-by-pixel rescaling of the data in the
* source image by multiplying the sample values for each pixel by a scale
* factor and then adding an offset. The scaled sample values are clipped
* to the minimum/maximum representable in the destination image.
* <p>
* The pseudo code for the rescaling operation is as follows:
* <pre>
*for each pixel from Source object {
* for each band/component of the pixel {
* dstElement = (srcElement*scaleFactor) + offset
* }
*}
* </pre>
* <p>
* For Rasters, rescaling operates on bands. The number of
* sets of scaling constants may be one, in which case the same constants
* are applied to all bands, or it must equal the number of Source
* Raster bands.
* <p>
* For BufferedImages, rescaling operates on color and alpha components.
* The number of sets of scaling constants may be one, in which case the
* same constants are applied to all color (but not alpha) components.
* Otherwise, the number of sets of scaling constants may
* equal the number of Source color components, in which case no
* rescaling of the alpha component (if present) is performed.
* If neither of these cases apply, the number of sets of scaling constants
* must equal the number of Source color components plus alpha components,
* in which case all color and alpha components are rescaled.
* <p>
* BufferedImage sources with premultiplied alpha data are treated in the same
* manner as non-premultiplied images for purposes of rescaling. That is,
* the rescaling is done per band on the raw data of the BufferedImage source
* without regard to whether the data is premultiplied. If a color conversion
* is required to the destination ColorModel, the premultiplied state of
* both source and destination will be taken into account for this step.
* <p>
* Images with an IndexColorModel cannot be rescaled.
* <p>
* If a RenderingHints object is specified in the constructor, the
* color rendering hint and the dithering hint may be used when color
* conversion is required.
* <p>
* Note that in-place operation is allowed (i.e. the source and destination can
* be the same object).
* @see java.awt.RenderingHints#KEY_COLOR_RENDERING
* @see java.awt.RenderingHints#KEY_DITHERING
*/
public class RescaleOp implements BufferedImageOp, RasterOp {
float[] scaleFactors;
float[] offsets;
int length = 0;
RenderingHints hints;
private int srcNbits;
private int dstNbits;
/**
* Constructs a new RescaleOp with the desired scale factors
* and offsets. The length of the scaleFactor and offset arrays
* must meet the restrictions stated in the class comments above.
* The RenderingHints argument may be null.
* @param scaleFactors the specified scale factors
* @param offsets the specified offsets
* @param hints the specified {@code RenderingHints}, or
* {@code null}
*/
public RescaleOp (float[] scaleFactors, float[] offsets,
RenderingHints hints) {
length = scaleFactors.length;
if (length > offsets.length) length = offsets.length;
this.scaleFactors = new float[length];
this.offsets = new float[length];
for (int i=0; i < length; i++) {
this.scaleFactors[i] = scaleFactors[i];
this.offsets[i] = offsets[i];
}
this.hints = hints;
}
/**
* Constructs a new RescaleOp with the desired scale factor
* and offset. The scaleFactor and offset will be applied to
* all bands in a source Raster and to all color (but not alpha)
* components in a BufferedImage.
* The RenderingHints argument may be null.
* @param scaleFactor the specified scale factor
* @param offset the specified offset
* @param hints the specified {@code RenderingHints}, or
* {@code null}
*/
public RescaleOp (float scaleFactor, float offset, RenderingHints hints) {
length = 1;
this.scaleFactors = new float[1];
this.offsets = new float[1];
this.scaleFactors[0] = scaleFactor;
this.offsets[0] = offset;
this.hints = hints;
}
/**
* Returns the scale factors in the given array. The array is also
* returned for convenience. If scaleFactors is null, a new array
* will be allocated.
* @param scaleFactors the array to contain the scale factors of
* this {@code RescaleOp}
* @return the scale factors of this {@code RescaleOp}.
*/
public final float[] getScaleFactors (float[] scaleFactors) {
if (scaleFactors == null) {
return this.scaleFactors.clone();
}
System.arraycopy (this.scaleFactors, 0, scaleFactors, 0,
Math.min(this.scaleFactors.length,
scaleFactors.length));
return scaleFactors;
}
/**
* Returns the offsets in the given array. The array is also returned
* for convenience. If offsets is null, a new array
* will be allocated.
* @param offsets the array to contain the offsets of
* this {@code RescaleOp}
* @return the offsets of this {@code RescaleOp}.
*/
public final float[] getOffsets(float[] offsets) {
if (offsets == null) {
return this.offsets.clone();
}
System.arraycopy (this.offsets, 0, offsets, 0,
Math.min(this.offsets.length, offsets.length));
return offsets;
}
/**
* Returns the number of scaling factors and offsets used in this
* RescaleOp.
* @return the number of scaling factors and offsets of this
* {@code RescaleOp}.
*/
public final int getNumFactors() {
return length;
}
/**
* Creates a ByteLookupTable to implement the rescale.
* The table may have either a SHORT or BYTE input.
* @param nElems Number of elements the table is to have.
* This will generally be 256 for byte and
* 65536 for short.
*/
private ByteLookupTable createByteLut(float[] scale,
float[] off,
int nBands,
int nElems) {
byte[][] lutData = new byte[nBands][nElems];
int band;
for (band=0; band<scale.length; band++) {
float bandScale = scale[band];
float bandOff = off[band];
byte[] bandLutData = lutData[band];
for (int i=0; i<nElems; i++) {
int val = (int)(i*bandScale + bandOff);
if ((val & 0xffffff00) != 0) {
if (val < 0) {
val = 0;
} else {
val = 255;
}
}
bandLutData[i] = (byte)val;
}
}
int maxToCopy = (nBands == 4 && scale.length == 4) ? 4 : 3;
while (band < lutData.length && band < maxToCopy) {
System.arraycopy(lutData[band-1], 0, lutData[band], 0, nElems);
band++;
}
if (nBands == 4 && band < nBands) {
byte[] bandLutData = lutData[band];
for (int i=0; i<nElems; i++) {
bandLutData[i] = (byte)i;
}
}
return new ByteLookupTable(0, lutData);
}
/**
* Creates a ShortLookupTable to implement the rescale.
* The table may have either a SHORT or BYTE input.
* @param nElems Number of elements the table is to have.
* This will generally be 256 for byte and
* 65536 for short.
*/
private ShortLookupTable createShortLut(float[] scale,
float[] off,
int nBands,
int nElems) {
short[][] lutData = new short[nBands][nElems];
int band = 0;
for (band=0; band<scale.length; band++) {
float bandScale = scale[band];
float bandOff = off[band];
short[] bandLutData = lutData[band];
for (int i=0; i<nElems; i++) {
int val = (int)(i*bandScale + bandOff);
if ((val & 0xffff0000) != 0) {
if (val < 0) {
val = 0;
} else {
val = 65535;
}
}
bandLutData[i] = (short)val;
}
}
int maxToCopy = (nBands == 4 && scale.length == 4) ? 4 : 3;
while (band < lutData.length && band < maxToCopy) {
System.arraycopy(lutData[band-1], 0, lutData[band], 0, nElems);
band++;
}
if (nBands == 4 && band < nBands) {
short[] bandLutData = lutData[band];
for (int i=0; i<nElems; i++) {
bandLutData[i] = (short)i;
}
}
return new ShortLookupTable(0, lutData);
}
/**
* Determines if the rescale can be performed as a lookup.
* The dst must be a byte or short type.
* The src must be less than 16 bits.
* All source band sizes must be the same and all dst band sizes
* must be the same.
*/
private boolean canUseLookup(Raster src, Raster dst) {
//
// Check that the src datatype is either a BYTE or SHORT
//
int datatype = src.getDataBuffer().getDataType();
if(datatype != DataBuffer.TYPE_BYTE &&
datatype != DataBuffer.TYPE_USHORT) {
return false;
}
//
// Check dst sample sizes. All must be 8 or 16 bits.
//
SampleModel dstSM = dst.getSampleModel();
dstNbits = dstSM.getSampleSize(0);
if (!(dstNbits == 8 || dstNbits == 16)) {
return false;
}
for (int i=1; i<src.getNumBands(); i++) {
int bandSize = dstSM.getSampleSize(i);
if (bandSize != dstNbits) {
return false;
}
}
//
// Check src sample sizes. All must be the same size
//
SampleModel srcSM = src.getSampleModel();
srcNbits = srcSM.getSampleSize(0);
if (srcNbits > 16) {
return false;
}
for (int i=1; i<src.getNumBands(); i++) {
int bandSize = srcSM.getSampleSize(i);
if (bandSize != srcNbits) {
return false;
}
}
if (dstSM instanceof ComponentSampleModel) {
ComponentSampleModel dsm = (ComponentSampleModel)dstSM;
if (dsm.getPixelStride() != dst.getNumBands()) {
return false;
}
}
if (srcSM instanceof ComponentSampleModel) {
ComponentSampleModel csm = (ComponentSampleModel)srcSM;
if (csm.getPixelStride() != src.getNumBands()) {
return false;
}
}
return true;
}
/**
* Rescales the source BufferedImage.
* If the color model in the source image is not the same as that
* in the destination image, the pixels will be converted
* in the destination. If the destination image is null,
* a BufferedImage will be created with the source ColorModel.
* An IllegalArgumentException may be thrown if the number of
* scaling factors/offsets in this object does not meet the
* restrictions stated in the class comments above, or if the
* source image has an IndexColorModel.
* @param src the {@code BufferedImage} to be filtered
* @param dst the destination for the filtering operation
* or {@code null}
* @return the filtered {@code BufferedImage}.
* @throws IllegalArgumentException if the {@code ColorModel}
* of {@code src} is an {@code IndexColorModel},
* or if the number of scaling factors and offsets in this
* {@code RescaleOp} do not meet the requirements
* stated in the class comments, or if the source and
* destination images differ in size.
*/
public final BufferedImage filter (BufferedImage src, BufferedImage dst) {
ColorModel srcCM = src.getColorModel();
ColorModel dstCM;
int numSrcColorComp = srcCM.getNumColorComponents();
int scaleConst = length;
if (srcCM instanceof IndexColorModel) {
throw new
IllegalArgumentException("Rescaling cannot be "+
"performed on an indexed image");
}
if (scaleConst != 1 && scaleConst != numSrcColorComp &&
scaleConst != srcCM.getNumComponents())
{
throw new IllegalArgumentException("Number of scaling constants "+
"does not equal the number of"+
" of color or color/alpha "+
" components");
}
boolean needToConvert = false;
boolean needToDraw = false;
// Include alpha
if (scaleConst > numSrcColorComp && srcCM.hasAlpha()) {
scaleConst = numSrcColorComp+1;
}
int width = src.getWidth();
int height = src.getHeight();
BufferedImage origDst = dst;
if (dst == null) {
dst = createCompatibleDestImage(src, null);
dstCM = srcCM;
}
else {
if (width != dst.getWidth()) {
throw new
IllegalArgumentException("Src width ("+width+
") not equal to dst width ("+
dst.getWidth()+")");
}
if (height != dst.getHeight()) {
throw new
IllegalArgumentException("Src height ("+height+
") not equal to dst height ("+
dst.getHeight()+")");
}
dstCM = dst.getColorModel();
if(srcCM.getColorSpace().getType() !=
dstCM.getColorSpace().getType()) {
needToConvert = true;
dst = createCompatibleDestImage(src, null);
}
}
//
// Try to use a native BI rescale operation first
//
if (ImagingLib.filter(this, src, dst) == null) {
if (src.getRaster().getNumBands() !=
dst.getRaster().getNumBands()) {
needToDraw = true;
dst = createCompatibleDestImage(src, null);
}
//
// Native BI rescale failed - convert to rasters
//
WritableRaster srcRaster = src.getRaster();
WritableRaster dstRaster = dst.getRaster();
//
// Call the raster filter method
//
filterRasterImpl(srcRaster, dstRaster, scaleConst, false);
}
if (needToDraw) {
Graphics2D g = origDst.createGraphics();
g.setComposite(AlphaComposite.Src);
g.drawImage(dst, 0, 0, width, height, null);
g.dispose();
}
if (needToConvert) {
// ColorModels are not the same
ColorConvertOp ccop = new ColorConvertOp(hints);
dst = ccop.filter(dst, origDst);
}
return dst;
}
/**
* Rescales the pixel data in the source Raster.
* If the destination Raster is null, a new Raster will be created.
* The source and destination must have the same number of bands.
* Otherwise, an IllegalArgumentException is thrown.
* Note that the number of scaling factors/offsets in this object must
* meet the restrictions stated in the class comments above.
* Otherwise, an IllegalArgumentException is thrown.
* @param src the {@code Raster} to be filtered
* @param dst the destination for the filtering operation
* or {@code null}
* @return the filtered {@code WritableRaster}.
* @throws IllegalArgumentException if {@code src} and
* {@code dst} do not have the same number of bands,
* or if the number of scaling factors and offsets in this
* {@code RescaleOp} do not meet the requirements
* stated in the class comments, or if the source and
* destination rasters differ in size.
*/
public final WritableRaster filter (Raster src, WritableRaster dst) {
return filterRasterImpl(src, dst, length, true);
}
private WritableRaster filterRasterImpl(Raster src, WritableRaster dst,
int scaleConst, boolean sCheck) {
int numBands = src.getNumBands();
int width = src.getWidth();
int height = src.getHeight();
int[] srcPix = null;
int step = 0;
int tidx = 0;
// Create a new destination Raster, if needed
if (dst == null) {
dst = createCompatibleDestRaster(src);
}
else if (height != dst.getHeight() || width != dst.getWidth()) {
throw new
IllegalArgumentException("Width or height of Rasters do not "+
"match");
}
else if (numBands != dst.getNumBands()) {
// Make sure that the number of bands are equal
throw new IllegalArgumentException("Number of bands in src "
+ numBands
+ " does not equal number of bands in dest "
+ dst.getNumBands());
}
// Make sure that the arrays match
// Make sure that the low/high/constant arrays match
if (sCheck && scaleConst != 1 && scaleConst != src.getNumBands()) {
throw new IllegalArgumentException("Number of scaling constants "+
"does not equal the number of"+
" of bands in the src raster");
}
//
// Try for a native raster rescale first
//
if (ImagingLib.filter(this, src, dst) != null) {
return dst;
}
//
// Native raster rescale failed.
// Try to see if a lookup operation can be used
//
if (canUseLookup(src, dst)) {
int srcNgray = (1 << srcNbits);
int dstNgray = (1 << dstNbits);
if (dstNgray == 256) {
ByteLookupTable lut = createByteLut(scaleFactors, offsets,
numBands, srcNgray);
LookupOp op = new LookupOp(lut, hints);
op.filter(src, dst);
} else {
ShortLookupTable lut = createShortLut(scaleFactors, offsets,
numBands, srcNgray);
LookupOp op = new LookupOp(lut, hints);
op.filter(src, dst);
}
} else {
//
// Fall back to the slow code
//
if (scaleConst > 1) {
step = 1;
}
int sminX = src.getMinX();
int sY = src.getMinY();
int dminX = dst.getMinX();
int dY = dst.getMinY();
int sX;
int dX;
//
// Determine bits per band to determine maxval for clamps.
// The min is assumed to be zero.
// REMIND: This must change if we ever support signed data types.
//
int nbits;
int[] dstMax = new int[numBands];
int[] dstMask = new int[numBands];
SampleModel dstSM = dst.getSampleModel();
for (int z=0; z<numBands; z++) {
nbits = dstSM.getSampleSize(z);
dstMax[z] = (1 << nbits) - 1;
dstMask[z] = ~(dstMax[z]);
}
int val;
for (int y=0; y < height; y++, sY++, dY++) {
dX = dminX;
sX = sminX;
for (int x = 0; x < width; x++, sX++, dX++) {
// Get data for all bands at this x,y position
srcPix = src.getPixel(sX, sY, srcPix);
tidx = 0;
for (int z=0; z<numBands; z++, tidx += step) {
if ((scaleConst == 1 || scaleConst == 3) &&
(z == 3) && (numBands == 4)) {
val = srcPix[z];
} else {
val = (int)(srcPix[z]*scaleFactors[tidx]
+ offsets[tidx]);
}
// Clamp
if ((val & dstMask[z]) != 0) {
if (val < 0) {
val = 0;
} else {
val = dstMax[z];
}
}
srcPix[z] = val;
}
// Put it back for all bands
dst.setPixel(dX, dY, srcPix);
}
}
}
return dst;
}
/**
* Returns the bounding box of the rescaled destination image. Since
* this is not a geometric operation, the bounding box does not
* change.
*/
public final Rectangle2D getBounds2D (BufferedImage src) {
return getBounds2D(src.getRaster());
}
/**
* Returns the bounding box of the rescaled destination Raster. Since
* this is not a geometric operation, the bounding box does not
* change.
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