* $RCSfile: MosaicOpImage.java,v $

*

* Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.

*

* Use is subject to license terms.

*

* $Revision: 1.2 $

* $Date: 2005/02/23 21:02:26 $

* $State: Exp $

*/package com.lightcrafts.media.jai.opimage;

    private static final int WEIGHT_TYPE_ALPHA = 1;

    private static final int WEIGHT_TYPE_ROI = 2;

    private static final int WEIGHT_TYPE_THRESHOLD = 3;

    protected MosaicType mosaicType;

    protected PlanarImage[] sourceAlpha;

    protected ROI[] sourceROI;

    protected double[][] sourceThreshold;

    protected double[] backgroundValues;

    protected int numBands;

    /** Integral background value. */

    protected int[] background;

    /** Integral thresholds. */

    protected int[][] threshold;

    protected boolean isAlphaBitmask = false;

    private BorderExtender sourceExtender;

    private BorderExtender zeroExtender;

    private PlanarImage[] roiImage;

    private static final ImageLayout getLayout(Vector sources,

                                               ImageLayout layout) {

        // Contingent variables.

        RenderedImage source0 = null;

        SampleModel targetSM = null;

        ColorModel targetCM = null;

        // Get source count (might be zero).

        int numSources = sources.size();

        if(numSources > 0) {

            // Get SampleModel and ColorModel from first source.

            source0 = (RenderedImage)sources.get(0);

            targetSM = source0.getSampleModel();

            targetCM = source0.getColorModel();

        } else if(layout != null &&

                  layout.isValid(ImageLayout.WIDTH_MASK |

                                 ImageLayout.HEIGHT_MASK |

                                 ImageLayout.SAMPLE_MODEL_MASK)) {

            // Get SampleModel and ColorModel from layout.

            targetSM = layout.getSampleModel(null);

            if(targetSM == null) {

                throw new IllegalArgumentException

                    (JaiI18N.getString("MosaicOpImage7"));

            }

        } else {

            throw new IllegalArgumentException

                (JaiI18N.getString("MosaicOpImage8"));

        }

        // Get data type, band count, and sample depth.

        int dataType = targetSM.getDataType();

        int numBands = targetSM.getNumBands();

        int sampleSize = targetSM.getSampleSize(0);

        // Sample size must equal that of first band.

        for(int i = 1; i < numBands; i++) {

            if(targetSM.getSampleSize(i) != sampleSize) {

                throw new IllegalArgumentException(JaiI18N.getString("MosaicOpImage1"));

            }

        }

        // Return a clone of ImageLayout passed in if no sources.

        // The input ImageLayout was checked for null above.

        if(numSources < 1) {

            return (ImageLayout)layout.clone();

        }

        // Check the other sources against the first.

        for(int i = 1; i < numSources; i++) {

            RenderedImage source = (RenderedImage)sources.get(i);

            SampleModel sourceSM = source.getSampleModel();

            // Data type and band count must be equal.

            if(sourceSM.getDataType() != dataType) {

                throw new IllegalArgumentException(JaiI18N.getString("MosaicOpImage2"));

            } else if(sourceSM.getNumBands() != numBands) {

                throw new IllegalArgumentException(JaiI18N.getString("MosaicOpImage3"));

            }

            // Sample size must be equal.

            for(int j = 0; j < numBands; j++) {

                if(sourceSM.getSampleSize(j) != sampleSize) {

                    throw new IllegalArgumentException(JaiI18N.getString("MosaicOpImage1"));

                }

            }

        }

        // Create a new layout or clone the one passed in.

        ImageLayout mosaicLayout = layout == null ?

            new ImageLayout() : (ImageLayout)layout.clone();

        // Determine the mosaic bounds.

        Rectangle mosaicBounds = new Rectangle();

        if(mosaicLayout.isValid(ImageLayout.MIN_X_MASK |

                                ImageLayout.MIN_Y_MASK |

                                ImageLayout.WIDTH_MASK |

                                ImageLayout.HEIGHT_MASK)) {

            // Set the mosaic bounds to the value given in the layout.

            mosaicBounds.setBounds(mosaicLayout.getMinX(null),

                                   mosaicLayout.getMinY(null),

                                   mosaicLayout.getWidth(null),

                                   mosaicLayout.getHeight(null));

        } else if(numSources > 0) {

            // Set the mosaic bounds to the union of source bounds.

            mosaicBounds.setBounds(source0.getMinX(), source0.getMinY(),

                                   source0.getWidth(), source0.getHeight());

            for(int i = 1; i < numSources; i++) {

                RenderedImage source = (RenderedImage)sources.get(i);

                Rectangle sourceBounds =

                    new Rectangle(source.getMinX(), source.getMinY(),

                                  source.getWidth(), source.getHeight());

                mosaicBounds = mosaicBounds.union(sourceBounds);

            }

        }

        // Set the mosaic bounds in the layout.

        mosaicLayout.setMinX(mosaicBounds.x);

        mosaicLayout.setMinY(mosaicBounds.y);

        mosaicLayout.setWidth(mosaicBounds.width);

        mosaicLayout.setHeight(mosaicBounds.height);

        // Check the SampleModel if defined.

        if(mosaicLayout.isValid(ImageLayout.SAMPLE_MODEL_MASK)) {

            // Get the SampleModel.

            SampleModel destSM = mosaicLayout.getSampleModel(null);

            // Unset SampleModel if differing band count or data type.

            boolean unsetSampleModel =

                destSM.getNumBands() != numBands ||

                destSM.getDataType() != dataType;

            // Unset SampleModel if differing sample size.

            for(int i = 0; !unsetSampleModel && i < numBands; i++) {

                if(destSM.getSampleSize(i) != sampleSize) {

                    unsetSampleModel = true;

                }

            }

            // Unset SampleModel if needed.

            if(unsetSampleModel) {

                mosaicLayout.unsetValid(ImageLayout.SAMPLE_MODEL_MASK);

            }

        }

        return mosaicLayout;

    }

    public MosaicOpImage(Vector sources,

                         ImageLayout layout,

                         Map config,

                         MosaicType mosaicType,

                         PlanarImage[] sourceAlpha,

                         ROI[] sourceROI,

                         double[][] sourceThreshold,

                         double[] backgroundValues) {

        super(sources, getLayout(sources, layout), config, true);

        // Set the band count.

        this.numBands = sampleModel.getNumBands();

        // Set the source count.

        int numSources = getNumSources();

        // Set the mosaic type.

        this.mosaicType = mosaicType;

        // Save the alpha array.

        this.sourceAlpha = null;

        if(sourceAlpha != null) {

            // Check alpha images.

            for(int i = 0; i < sourceAlpha.length; i++) {

                if(sourceAlpha[i] != null) {

                    SampleModel alphaSM = sourceAlpha[i].getSampleModel();

                    if(alphaSM.getNumBands() != 1) {

                        throw new IllegalArgumentException(JaiI18N.getString("MosaicOpImage4"));

                    } else if(alphaSM.getDataType() !=

                              sampleModel.getDataType()) {

                        throw new IllegalArgumentException(JaiI18N.getString("MosaicOpImage5"));

                    } else if(alphaSM.getSampleSize(0) !=

                              sampleModel.getSampleSize(0)) {

                        throw new IllegalArgumentException(JaiI18N.getString("MosaicOpImage6"));

                    }

                }

            }

            this.sourceAlpha = new PlanarImage[numSources];

            System.arraycopy(sourceAlpha, 0,

                             this.sourceAlpha, 0,

                             Math.min(sourceAlpha.length, numSources));

        }

        // Save the ROI array.

        this.sourceROI = null;

        if(sourceROI != null) {

            this.sourceROI = new ROI[numSources];

            System.arraycopy(sourceROI, 0,

                             this.sourceROI, 0,

                             Math.min(sourceROI.length, numSources));

        }

        // isAlphaBitmask is true if and only if type is blend and an

        // alpha image is supplied for each source.

        this.isAlphaBitmask =

            !(mosaicType == MosaicDescriptor.MOSAIC_TYPE_BLEND &&

              sourceAlpha != null && !(sourceAlpha.length < numSources));

        if(!this.isAlphaBitmask) {

            for(int i = 0; i < numSources; i++) {

                if(sourceAlpha[i] == null) {

                    this.isAlphaBitmask = true;

                    break;

                }

            }

        }

        // Copy the threshold values according to the specification.

        this.sourceThreshold = new double[numSources][numBands];

        // Ensure the parameter is non-null and has one value.

        if(sourceThreshold == null) {

            sourceThreshold = new double[][] {{1.0}};

        }

        for(int i = 0; i < numSources; i++) {

            // If there's an array for this source, use it.

            if(i < sourceThreshold.length && sourceThreshold[i] != null) {

                if(sourceThreshold[i].length < numBands) {

                    // If the array is less than numBands, fill with element 0.

                    Arrays.fill(this.sourceThreshold[i],

                                sourceThreshold[i][0]);

                } else {

                    // Copy the whole array.

                    System.arraycopy(sourceThreshold[i], 0,

                                     this.sourceThreshold[i], 0,

                                     numBands);

                }

            } else {

                // Beyond the array or a null element: use the zeroth array.

                this.sourceThreshold[i] = this.sourceThreshold[0];

            }

        }

        // Initialize the integral thresholds.

        this.threshold = new int[numSources][numBands];

        for(int i = 0; i < numSources; i++) {

            for(int j = 0; j < numBands; j++) {

                // Truncate as the specified comparison is ">=".

                this.threshold[i][j] = (int)this.sourceThreshold[i][j];

            }

        }

        // Copy the background values per the specification.

        this.backgroundValues = new double[numBands];

        if(backgroundValues == null) {

            backgroundValues = new double[] {0.0};

        }

        if(backgroundValues.length < numBands) {

            Arrays.fill(this.backgroundValues, backgroundValues[0]);

        } else {

            System.arraycopy(backgroundValues, 0,

                             this.backgroundValues, 0,

                             numBands);

        }

        // Clamp the floating point values for the integral cases.

        this.background = new int[this.backgroundValues.length];

        int dataType = sampleModel.getDataType();

        for(int i = 0; i < this.background.length; i++) {

            switch (dataType) {

            case DataBuffer.TYPE_BYTE:

                this.background[i] =

                    ImageUtil.clampRoundByte(this.backgroundValues[i]);

                break;

            case DataBuffer.TYPE_USHORT:

                this.background[i] =

                    ImageUtil.clampRoundUShort(this.backgroundValues[i]);

                break;

            case DataBuffer.TYPE_SHORT:

                this.background[i] =

                    ImageUtil.clampRoundShort(this.backgroundValues[i]);

                break;

            case DataBuffer.TYPE_INT:

                this.background[i] =

                    ImageUtil.clampRoundInt(this.backgroundValues[i]);

                break;

            default:

            }

        }

        // Determine constant value for source border extension.

        double sourceExtensionConstant;

        switch (dataType) {

        case DataBuffer.TYPE_BYTE:

            sourceExtensionConstant = 0.0;

            break;

        case DataBuffer.TYPE_USHORT:

            sourceExtensionConstant = 0.0;

            break;

        case DataBuffer.TYPE_SHORT:

            sourceExtensionConstant = Short.MIN_VALUE;

            break;

        case DataBuffer.TYPE_INT:

            sourceExtensionConstant = Integer.MIN_VALUE;

            break;

        case DataBuffer.TYPE_FLOAT:

            sourceExtensionConstant = -Float.MAX_VALUE;

            break;

        case DataBuffer.TYPE_DOUBLE:

        default:

            sourceExtensionConstant = -Double.MAX_VALUE;

        }

        // Extend the sources filling with the minimum possible value

        // on account of the threshold technique.

        this.sourceExtender =

            sourceExtensionConstant == 0.0 ?

            BorderExtender.createInstance(BorderExtender.BORDER_ZERO) :

            new BorderExtenderConstant(new double[] {sourceExtensionConstant});

        // Extends alpha or ROI data with zeros.

        if(sourceAlpha != null || sourceROI != null) {

            this.zeroExtender =

                BorderExtender.createInstance(BorderExtender.BORDER_ZERO);

        }

        // Get the ROI images.

        if(sourceROI != null) {

            roiImage = new PlanarImage[numSources];

            for(int i = 0; i < sourceROI.length; i++) {

                if(sourceROI[i] != null) {

                    roiImage[i] = sourceROI[i].getAsImage();

                }

            }

        }

    }

    public Rectangle mapDestRect(Rectangle destRect,

                                 int sourceIndex) {

        if(destRect == null) {

            throw new IllegalArgumentException(JaiI18N.getString("Generic0"));

        }

        if(sourceIndex < 0 || sourceIndex >= getNumSources()) {

            throw new IllegalArgumentException(JaiI18N.getString("Generic1"));

        }

        return destRect.intersection(getSourceImage(sourceIndex).getBounds());

    }

    public Rectangle mapSourceRect(Rectangle sourceRect,

                                   int sourceIndex) {

        if(sourceRect == null) {

            throw new IllegalArgumentException(JaiI18N.getString("Generic0"));

        }

        if(sourceIndex < 0 || sourceIndex >= getNumSources()) {

            throw new IllegalArgumentException(JaiI18N.getString("Generic1"));

        }

        return sourceRect.intersection(getBounds());

    }

    public Raster computeTile(int tileX, int tileY) {

        // Create a new Raster.

        WritableRaster dest = createWritableRaster(sampleModel,

                                                   new Point(tileXToX(tileX),

                                                             tileYToY(tileY)));

        // Determine the active area; tile intersects with image's bounds.

        Rectangle destRect = getTileRect(tileX, tileY);

        int numSources = getNumSources();

        Raster[] rasterSources = new Raster[numSources];

        Raster[] alpha = sourceAlpha != null ?

            new Raster[numSources] : null;

        Raster[] roi = sourceROI != null ?

            new Raster[numSources] : null;

        // Cobble areas

        for (int i = 0; i < numSources; i++) {

            PlanarImage source = getSourceImage(i);

            Rectangle srcRect = mapDestRect(destRect, i);

            // If srcRect is empty, set the Raster for this source to

            // null; otherwise pass srcRect to getData(). If srcRect

            // is null, getData() will return a Raster containing the

            // data of the entire source image.

            rasterSources[i] = srcRect != null && srcRect.isEmpty() ?

                null : source.getExtendedData(destRect, sourceExtender);

            if(rasterSources[i] != null) {

                if(sourceAlpha != null && sourceAlpha[i] != null) {

                    alpha[i] = sourceAlpha[i].getExtendedData(destRect,

                                                              zeroExtender);

                }

                if(sourceROI != null && sourceROI[i] != null) {

                    roi[i] = roiImage[i].getExtendedData(destRect,

                                                         zeroExtender);

                }

            }

        }

        computeRect(rasterSources, dest, destRect, alpha, roi);

        for (int i = 0; i < numSources; i++) {

            Raster sourceData = rasterSources[i];

            if(sourceData != null) {

                PlanarImage source = getSourceImage(i);

                // Recycle the source tile

                if(source.overlapsMultipleTiles(sourceData.getBounds())) {

                    recycleTile(sourceData);

                }

            }

        }

        return dest;

    }

    protected void computeRect(Raster[] sources,

                               WritableRaster dest,

                               Rectangle destRect) {

        computeRect(sources, dest, destRect, null, null);

    }

    protected void computeRect(Raster[] sources,

                               WritableRaster dest,

                               Rectangle destRect,

                               Raster[] alphaRaster,

                               Raster[] roiRaster) {

        // Save the source count.

        int numSources = sources.length;

        // Put all non-null sources in a list.

        ArrayList sourceList = new ArrayList(numSources);

        for(int i = 0; i < numSources; i++) {

            if(sources[i] != null) {

                sourceList.add(sources[i]);

            }

        }

        // Clear the background and return if no sources.

        int numNonNullSources = sourceList.size();

        if(numNonNullSources == 0) {

            ImageUtil.fillBackground(dest, destRect, backgroundValues);

            return;

        }

        // Determine the format tag id.

        SampleModel[] sourceSM = new SampleModel[numNonNullSources];

        for(int i = 0; i < numNonNullSources; i++) {

            sourceSM[i] = ((Raster)sourceList.get(i)).getSampleModel();

        }

        int formatTagID =

            RasterAccessor.findCompatibleTag(sourceSM,

                                             dest.getSampleModel());

        // Create source accessors.

        RasterAccessor[] s = new RasterAccessor[numSources];

        for(int i = 0; i < numSources; i++) {

            if(sources[i] != null) {

                RasterFormatTag formatTag =

                    new RasterFormatTag(sources[i].getSampleModel(),

                                        formatTagID);

                s[i] = new RasterAccessor(sources[i], destRect, formatTag,

                                          null);

            }

        }

        // Create dest accessor.

        RasterAccessor d =

            new RasterAccessor(dest, destRect,

                               new RasterFormatTag(dest.getSampleModel(),

                                                   formatTagID),

                               null);

        // Create the alpha accessors.

        RasterAccessor[] a = new RasterAccessor[numSources];

        if(alphaRaster != null) {

            for(int i = 0; i < numSources; i++) {

                if(alphaRaster[i] != null) {

                    SampleModel alphaSM = alphaRaster[i].getSampleModel();

                    int alphaFormatTagID =

                        RasterAccessor.findCompatibleTag(null, alphaSM);

                    RasterFormatTag alphaFormatTag =

                        new RasterFormatTag(alphaSM, alphaFormatTagID);

                    a[i] = new RasterAccessor(alphaRaster[i], destRect, 

                                              alphaFormatTag,

                                              sourceAlpha[i].getColorModel());

                }

            }

        }

        // Branch to data type-specific method.

        switch (d.getDataType()) {

        case DataBuffer.TYPE_BYTE:

            computeRectByte(s, d, a, roiRaster);

            break;

        case DataBuffer.TYPE_USHORT:

            computeRectUShort(s, d, a, roiRaster);

            break;

        case DataBuffer.TYPE_SHORT:

            computeRectShort(s, d, a, roiRaster);

            break;

        case DataBuffer.TYPE_INT:

            computeRectInt(s, d, a, roiRaster);

            break;

        case DataBuffer.TYPE_FLOAT:

            computeRectFloat(s, d, a, roiRaster);

            break;

        case DataBuffer.TYPE_DOUBLE:

            computeRectDouble(s, d, a, roiRaster);

            break;

        }

        d.copyDataToRaster();

    }

    private void computeRectByte(RasterAccessor[] src,

                                 RasterAccessor dst,

                                 RasterAccessor[] alfa,

                                 Raster[] roi) {

        // Save the source count.

        int numSources = src.length;

        // Allocate stride, offset, and data arrays for sources.

        int[] srcLineStride = new int[numSources];

        int[] srcPixelStride = new int[numSources];

        int[][] srcBandOffsets = new int[numSources][];

        byte[][][] srcData = new byte[numSources][][];

        // Initialize stride, offset, and data arrays for sources.

        for(int i = 0; i < numSources; i++) {

            if(src[i] != null) {

                srcLineStride[i] = src[i].getScanlineStride();

                srcPixelStride[i] = src[i].getPixelStride();

                srcBandOffsets[i] = src[i].getBandOffsets();

                srcData[i] = src[i].getByteDataArrays();

            }

        }

        // Initialize destination variables.

        int dstMinX = dst.getX();

        int dstMinY = dst.getY();

        int dstWidth = dst.getWidth();

        int dstHeight = dst.getHeight();

        int dstMaxX = dstMinX + dstWidth;  // x max exclusive

        int dstMaxY = dstMinY + dstHeight; // y max exclusive

        int dstBands = dst.getNumBands();

        int dstLineStride = dst.getScanlineStride();

        int dstPixelStride = dst.getPixelStride();

        int[] dstBandOffsets = dst.getBandOffsets();

        byte[][] dstData = dst.getByteDataArrays();

        // Check for alpha.

        boolean hasAlpha = false;

        for(int i = 0; i < numSources; i++) {

            if(alfa[i] != null) {

                hasAlpha = true;

                break;

            }

        }

        // Declare alpha channel arrays.

        int[] alfaLineStride = null;

        int[] alfaPixelStride = null;

        int[][] alfaBandOffsets = null;

        byte[][][] alfaData = null;

        if(hasAlpha) {

            // Allocate stride, offset, and data arrays for alpha channels.

            alfaLineStride = new int[numSources];

            alfaPixelStride = new int[numSources];

            alfaBandOffsets = new int[numSources][];

            alfaData = new byte[numSources][][];

            // Initialize stride, offset, and data arrays for alpha channels.

            for(int i = 0; i < numSources; i++) {

                if(alfa[i] != null) {

                    alfaLineStride[i] = alfa[i].getScanlineStride();

                    alfaPixelStride[i] = alfa[i].getPixelStride();

                    alfaBandOffsets[i] = alfa[i].getBandOffsets();

                    alfaData[i] = alfa[i].getByteDataArrays();

                }

            }

        }

        // Initialize weight type arrays.

        int[] weightTypes = new int[numSources];

        for(int i = 0; i < numSources; i++) {

            weightTypes[i] = WEIGHT_TYPE_THRESHOLD;

            if(alfa[i] != null) {

                weightTypes[i] = WEIGHT_TYPE_ALPHA;

            } else if(sourceROI != null && sourceROI[i] != null) {

                weightTypes[i] = WEIGHT_TYPE_ROI;

            }

        }

        // Set up source offset and data variabls.

        int[] sLineOffsets = new int[numSources];

        int[] sPixelOffsets = new int[numSources];

        byte[][] sBandData = new byte[numSources][];

        // Set up alpha offset and data variabls.

        int[] aLineOffsets = null;

        int[] aPixelOffsets = null;

        byte[][] aBandData = null;

        if(hasAlpha) {

            aLineOffsets = new int[numSources];

            aPixelOffsets = new int[numSources];

            aBandData = new byte[numSources][];

        }

        for(int b = 0; b < dstBands; b++) {

            // Initialize source and alpha band array and line offsets.

            for(int s = 0; s < numSources; s++) {

                if(src[s] != null) {

                    sBandData[s] = srcData[s][b];

                    sLineOffsets[s] = srcBandOffsets[s][b];

                }

                if(weightTypes[s] == WEIGHT_TYPE_ALPHA) {

                    aBandData[s] = alfaData[s][0];

                    aLineOffsets[s] = alfaBandOffsets[s][0];

                }

            }

            // Initialize destination band array and line offsets.

            byte[] dBandData = dstData[b];

            int dLineOffset = dstBandOffsets[b];

            if(mosaicType == MosaicDescriptor.MOSAIC_TYPE_OVERLAY) {

                for(int dstY = dstMinY; dstY < dstMaxY; dstY++) {

                    // Initialize source and alpha pixel offsets and

                    // update line offsets.

                    for(int s = 0; s < numSources; s++) {

                        if(src[s] != null) {

                            sPixelOffsets[s] = sLineOffsets[s];

                            sLineOffsets[s] += srcLineStride[s];

                        }

                        if(alfa[s] != null) {

                            aPixelOffsets[s] = aLineOffsets[s];

                            aLineOffsets[s] += alfaLineStride[s];

                        }

                    }

                    // Initialize destination pixel offset and update

                    // line offset.

                    int dPixelOffset = dLineOffset;

                    dLineOffset += dstLineStride;

                    for(int dstX = dstMinX; dstX < dstMaxX; dstX++) {

                        // Unset destination update flag.

                        boolean setDestValue = false;

                        // Loop over source until a non-zero weight is

                        // encountered.

                        for(int s = 0; s < numSources; s++) {

                            if(src[s] == null) continue;

                            byte sourceValue =

                                sBandData[s][sPixelOffsets[s]];

                            sPixelOffsets[s] += srcPixelStride[s];

                            switch(weightTypes[s]) {

                            case WEIGHT_TYPE_ALPHA:

                                setDestValue =

                                    aBandData[s][aPixelOffsets[s]] != 0;

                                aPixelOffsets[s] += alfaPixelStride[s];

                                break;

                            case WEIGHT_TYPE_ROI:

                                setDestValue =

                                    roi[s].getSample(dstX, dstY, 0) > 0;

                                break;

                            default: // WEIGHT_TYPE_THRESHOLD

                                setDestValue =

                                    (sourceValue&0xff) >=

                                    sourceThreshold[s][b];

                            }

                            // Set the destination value if a non-zero

                            // weight was found.

                            if(setDestValue) {

                                dBandData[dPixelOffset] = sourceValue;

                                // Increment offset of subsequent sources.

                                for(int k = s + 1; k < numSources; k++) {

                                    if(src[k] != null) {

                                        sPixelOffsets[k] += srcPixelStride[k];

                                    }

                                    if(alfa[k] != null) {

                                        aPixelOffsets[k] += alfaPixelStride[k];

                                    }

                                }

                                break;

                            }

                        }

                        // Set the destination value to the background if

                        // no value was set.

                        if(!setDestValue) {

                            dBandData[dPixelOffset] = (byte)background[b];

                        }

                        dPixelOffset += dstPixelStride;

                    }

                }

            } else { // mosaicType == MosaicDescriptor.MOSAIC_TYPE_BLEND

                for(int dstY = dstMinY; dstY < dstMaxY; dstY++) {

                    // Initialize source and alpha pixel offsets and

                    // update line offsets.

                    for(int s = 0; s < numSources; s++) {

                        if(src[s] != null) {

                            sPixelOffsets[s] = sLineOffsets[s];

                            sLineOffsets[s] += srcLineStride[s];

                        }

                        if(weightTypes[s] == WEIGHT_TYPE_ALPHA) {

                            aPixelOffsets[s] = aLineOffsets[s];

                            aLineOffsets[s] += alfaLineStride[s];

                        }

                    }

                    // Initialize destination pixel offset and update

                    // line offset.

                    int dPixelOffset = dLineOffset;

                    dLineOffset += dstLineStride;

                    for(int dstX = dstMinX; dstX < dstMaxX; dstX++) {

                        // Clear values for blending ratio.

                        float numerator = 0.0F;

                        float denominator = 0.0F;

                        // Accumulate into numerator and denominator.

                        for(int s = 0; s < numSources; s++) {

                            if(src[s] == null) continue;

                            byte sourceValue =

                                sBandData[s][sPixelOffsets[s]];

                            sPixelOffsets[s] += srcPixelStride[s];

                            float weight = 0.0F;

                            switch(weightTypes[s]) {

                            case WEIGHT_TYPE_ALPHA:

                                weight = (aBandData[s][aPixelOffsets[s]]&0xff);

                                if(weight > 0.0F && isAlphaBitmask) {

                                    weight = 1.0F;

                                } else {

                                    weight /= 255.0F;

                                }

                                aPixelOffsets[s] += alfaPixelStride[s];

                                break;

                            case WEIGHT_TYPE_ROI:

                                weight =

                                    roi[s].getSample(dstX, dstY, 0) > 0 ?

                                    1.0F : 0.0F;

                                break;

                            default: // WEIGHT_TYPE_THRESHOLD

                                weight =

                                    (sourceValue&0xff) >=

                                    sourceThreshold[s][b] ?

                                    1.0F : 0.0F;

                            }

                            // Update numerator and denominator.

                            numerator += (weight*(sourceValue&0xff));

                            denominator += weight;

                        }

                        // Clear the background if all weights were zero,

                        // otherwise blend the values.

                        if(denominator == 0.0) {