/*

   Licensed to the Apache Software Foundation (ASF) under one or more
   contributor license agreements.  See the NOTICE file distributed with
   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
   (the "License"); you may not use this file except in compliance with
   the License.  You may obtain a copy of the License at

       http://www.apache.org/licenses/LICENSE-2.0

   Unless required by applicable law or agreed to in writing, software
   distributed under the License is distributed on an "AS IS" BASIS,
   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   See the License for the specific language governing permissions and
   limitations under the License.

 */
package org.apache.batik.ext.awt.image.rendered;


import java.awt.color.ColorSpace;
import java.awt.image.BandCombineOp;
import java.awt.image.BufferedImage;
import java.awt.image.ColorConvertOp;
import java.awt.image.ColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.DataBufferInt;
import java.awt.image.Raster;
import java.awt.image.SampleModel;
import java.awt.image.SinglePixelPackedSampleModel;
import java.awt.image.WritableRaster;

import org.apache.batik.ext.awt.image.GraphicsUtil;

/**
 * This function will tranform an image from any colorspace into a
 * luminance image.  The alpha channel if any will be copied to the
 * new image.
 *
 * @author <a href="mailto:Thomas.DeWeeese@Kodak.com">Thomas DeWeese</a>
 * @version $Id: Any2sRGBRed.java 537934 2007-05-14 18:23:15Z dvholten $
 */
public class Any2sRGBRed extends AbstractRed {

    boolean srcIsLsRGB = false;

    /**
     * Construct a luminance image from src.
     *
     * @param src The image to convert to a luminance image
     */
    public Any2sRGBRed(CachableRed src) {
        super(src,src.getBounds(),
              fixColorModel(src),
              fixSampleModel(src),
              src.getTileGridXOffset(),
              src.getTileGridYOffset(),
              null);

        ColorModel srcCM = src.getColorModel();
        if (srcCM == null) return;
        ColorSpace srcCS = srcCM.getColorSpace();
        if (srcCS == ColorSpace.getInstance(ColorSpace.CS_LINEAR_RGB))
            srcIsLsRGB = true;
    }

    public static boolean is_INT_PACK_COMP(SampleModel sm) {
        if(!(sm instanceof SinglePixelPackedSampleModel)) return false;

        // Check transfer types
        if(sm.getDataType() != DataBuffer.TYPE_INT)       return false;

        SinglePixelPackedSampleModel sppsm;
        sppsm = (SinglePixelPackedSampleModel)sm;

        int [] masks = sppsm.getBitMasks();
        if ((masks.length != 3) && (masks.length != 4)) return false;
        if(masks[0] != 0x00ff0000) return false;
        if(masks[1] != 0x0000ff00) return false;
        if(masks[2] != 0x000000ff) return false;
        if ((masks.length == 4) &&
            (masks[3] != 0xff000000)) return false;

        return true;
   }

    /**
     * Exponent for linear to sRGB convertion
     */
    private static final double GAMMA = 2.4;

    /**
     * Lookup tables for RGB lookups. The linearToSRGBLut is used
     * when noise values are considered to be on a linearScale. The
     * linearToLinear table is used when the values are considered to
     * be on the sRGB scale to begin with.
     */
    private static final int[] linearToSRGBLut = new int[256];

    static {
        final double scale = 1.0/255;
        final double exp   = 1.0/GAMMA;
        // System.out.print("L2S: ");
        for(int i=0; i<256; i++){
            double value = i*scale;
            if(value <= 0.0031308)
                value *= 12.92;
            else
                value = 1.055 * Math.pow(value, exp) - 0.055;

            linearToSRGBLut[i] = (int)Math.round(value*255.0);
            // System.out.print(linearToSRGBLut[i] + ",");
        }
        // System.out.println("");
    }

    public static WritableRaster applyLut_INT(WritableRaster wr,
                                              final int []lut) {
        SinglePixelPackedSampleModel sm =
            (SinglePixelPackedSampleModel)wr.getSampleModel();
        DataBufferInt db = (DataBufferInt)wr.getDataBuffer();

        final int     srcBase
            = (db.getOffset() +
               sm.getOffset(wr.getMinX()-wr.getSampleModelTranslateX(),
                            wr.getMinY()-wr.getSampleModelTranslateY()));
        // Access the pixel data array
        final int[] pixels   = db.getBankData()[0];
        final int width      = wr.getWidth();
        final int height     = wr.getHeight();
        final int scanStride = sm.getScanlineStride();

        int end, pix;

        // For alpha premult we need to multiply all comps.
        for (int y=0; y<height; y++) {
            int sp  = srcBase + y*scanStride;
            end = sp + width;

            while (sp<end) {
                pix = pixels[sp];
                pixels[sp] =
                    ((     pix      &0xFF000000)|
                     (lut[(pix>>>16)&0xFF]<<16) |
                     (lut[(pix>>> 8)&0xFF]<< 8) |
                     (lut[(pix     )&0xFF]    ));
                sp++;
            }
        }

        return wr;
    }

    public WritableRaster copyData(WritableRaster wr) {

        // Get my source.
        CachableRed src   = (CachableRed)getSources().get(0);
        ColorModel  srcCM = src.getColorModel();
        SampleModel srcSM = src.getSampleModel();


        // Fast case, Linear SRGB source, INT Pack writable raster...
        if (srcIsLsRGB &&
            is_INT_PACK_COMP(wr.getSampleModel())) {
            src.copyData(wr);
            if (srcCM.hasAlpha())
                GraphicsUtil.coerceData(wr, srcCM, false);
            applyLut_INT(wr, linearToSRGBLut);
            return wr;
        }

        if (srcCM == null) {
            // We don't really know much about this source, let's
            // guess based on the number of bands...

            float [][] matrix = null;
            switch (srcSM.getNumBands()) {
            case 1:
                matrix = new float[3][1];
                matrix[0][0] = 1; // Red
                matrix[1][0] = 1; // Grn
                matrix[2][0] = 1; // Blu
                break;
            case 2:
                matrix = new float[4][2];
                matrix[0][0] = 1; // Red
                matrix[1][0] = 1; // Grn
                matrix[2][0] = 1; // Blu
                matrix[3][1] = 1; // Alpha
                break;
            case 3:
                matrix = new float[3][3];
                matrix[0][0] = 1; // Red
                matrix[1][1] = 1; // Grn
                matrix[2][2] = 1; // Blu
                break;
            default:
                matrix = new float[4][srcSM.getNumBands()];
                matrix[0][0] = 1; // Red
                matrix[1][1] = 1; // Grn
                matrix[2][2] = 1; // Blu
                matrix[3][3] = 1; // Alpha
                break;
            }
            Raster srcRas = src.getData(wr.getBounds());
            BandCombineOp op = new BandCombineOp(matrix, null);
            op.filter(srcRas, wr);
            return wr;
        }

        if (srcCM.getColorSpace() ==
            ColorSpace.getInstance(ColorSpace.CS_GRAY)) {

            // This is a little bit of a hack.  There is only
            // a linear grayscale ICC profile in the JDK so
            // many things use this when the data _really_
            // has sRGB gamma applied.
            try {
                float [][] matrix = null;
                switch (srcSM.getNumBands()) {
                case 1:
                    matrix = new float[3][1];
                    matrix[0][0] = 1; // Red
                    matrix[1][0] = 1; // Grn
                    matrix[2][0] = 1; // Blu
                    break;
                case 2:
                default:
                    matrix = new float[4][2];
                    matrix[0][0] = 1; // Red
                    matrix[1][0] = 1; // Grn
                    matrix[2][0] = 1; // Blu
                    matrix[3][1] = 1; // Alpha
                    break;
                }
                Raster srcRas = src.getData(wr.getBounds());
                BandCombineOp op = new BandCombineOp(matrix, null);
                op.filter(srcRas, wr);
            } catch (Throwable t) {
                t.printStackTrace();
            }
            return wr;
        }

        ColorModel dstCM = getColorModel();
        if (srcCM.getColorSpace() == dstCM.getColorSpace()) {
            // No transform needed, just reformat data...
            // System.out.println("Bypassing");

            if (is_INT_PACK_COMP(srcSM))
                src.copyData(wr);
            else
                GraphicsUtil.copyData(src.getData(wr.getBounds()), wr);

            return wr;
        }

        Raster srcRas = src.getData(wr.getBounds());
        WritableRaster srcWr  = (WritableRaster)srcRas;

        // Divide out alpha if we have it.  We need to do this since
        // the color convert may not be a linear operation which may
        // lead to out of range values.
        ColorModel srcBICM = srcCM;
        if (srcCM.hasAlpha())
            srcBICM = GraphicsUtil.coerceData(srcWr, srcCM, false);

        BufferedImage srcBI, dstBI;
        srcBI = new BufferedImage(srcBICM,
                                  srcWr.createWritableTranslatedChild(0,0),
                                  false,
                                  null);

        // System.out.println("src: " + srcBI.getWidth() + "x" +
        //                    srcBI.getHeight());

        ColorConvertOp op = new ColorConvertOp(dstCM.getColorSpace(),
                                               null);
        dstBI = op.filter(srcBI, null);

        // System.out.println("After filter:");

        WritableRaster wr00 = wr.createWritableTranslatedChild(0,0);
        for (int i=0; i<dstCM.getColorSpace().getNumComponents(); i++)
            copyBand(dstBI.getRaster(), i, wr00,    i);

        if (dstCM.hasAlpha())
            copyBand(srcWr, srcSM.getNumBands()-1,
                     wr,    getSampleModel().getNumBands()-1);
        return wr;
    }

    /**
     * This function 'fixes' the source's color model.  Right now
     * it just selects if it should have one or two bands based on
     * if the source had an alpha channel.
     */
    protected static ColorModel fixColorModel(CachableRed src) {
        ColorModel  cm = src.getColorModel();
        if (cm != null) {
            if (cm.hasAlpha())
                return GraphicsUtil.sRGB_Unpre;

            return GraphicsUtil.sRGB;
        }
        else {
            // No ColorModel so try to make some intelligent
            // decisions based just on the number of bands...
            // 1 bands -> replicated into RGB
            // 2 bands -> Band 0 replicated into RGB & Band 1 -> alpha premult
            // 3 bands -> sRGB (not-linear?)
            // 4 bands -> sRGB premult (not-linear?)
            SampleModel sm = src.getSampleModel();

            switch (sm.getNumBands()) {
            case 1:
                return GraphicsUtil.sRGB;
            case 2:
                return GraphicsUtil.sRGB_Unpre;
            case 3:
                return GraphicsUtil.sRGB;
            }
            return GraphicsUtil.sRGB_Unpre;
        }
    }

    /**
     * This function 'fixes' the source's sample model.
     * Right now it just selects if it should have 3 or 4 bands
     * based on if the source had an alpha channel.
     */
    protected static SampleModel fixSampleModel(CachableRed src) {
        SampleModel sm = src.getSampleModel();
        ColorModel  cm = src.getColorModel();

        boolean alpha = false;

        if (cm != null)
            alpha = cm.hasAlpha();
        else {
            switch (sm.getNumBands()) {
            case 1: case 3:
                alpha = false;
                break;
            default:
                alpha = true;
                break;
            }
        }
        if (alpha)
            return new SinglePixelPackedSampleModel
                (DataBuffer.TYPE_INT,
                 sm.getWidth(),
                 sm.getHeight(),
                 new int [] {0xFF0000, 0xFF00, 0xFF, 0xFF000000});
        else
            return new SinglePixelPackedSampleModel
                (DataBuffer.TYPE_INT,
                 sm.getWidth(),
                 sm.getHeight(),
                 new int [] {0xFF0000, 0xFF00, 0xFF});
    }
}
