affinetransformop.java

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/*
 * @(#)AffineTransformOp.java	1.60 03/01/23
 *
 * Copyright 2003 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

package java.awt.image;

import java.awt.geom.AffineTransform;
import java.awt.geom.NoninvertibleTransformException;
import java.awt.geom.Rectangle2D;
import java.awt.geom.Point2D;
import java.awt.AlphaComposite;
import java.awt.GraphicsEnvironment;
import java.awt.Rectangle;
import java.awt.RenderingHints;
import java.awt.Transparency;
import sun.awt.image.ImagingLib;

/**
 * This class uses an affine transform to perform a linear mapping from
 * 2D coordinates in the source image or <CODE>Raster</CODE> to 2D coordinates 
 * in the destination image or <CODE>Raster</CODE>.
 * The type of interpolation that is used is specified through a constructor, 
 * either by a <CODE>RenderingHints</CODE> object or by one of the integer 
 * interpolation types defined in this class.
 * <p>
 * If a <CODE>RenderingHints</CODE> object is specified in the constructor, the
 * interpolation hint and the rendering quality hint are used to set
 * the interpolation type for this operation.  The color rendering hint
 * and the dithering hint can be used when color conversion is required.
 * <p>
 * Note that the following constraints have to be met:
 * <ul>
 * <li>The source and destination must be different.
 * <li>For <CODE>Raster</CODE> objects, the number of bands in the source must 
 * be equal to the number of bands in the destination.
 * </ul>
 * @see AffineTransform
 * @see BufferedImageFilter
 * @see java.awt.RenderingHints#KEY_INTERPOLATION
 * @see java.awt.RenderingHints#KEY_RENDERING
 * @see java.awt.RenderingHints#KEY_COLOR_RENDERING
 * @see java.awt.RenderingHints#KEY_DITHERING
 * @version 16 Apr 1998
 */
public class AffineTransformOp implements BufferedImageOp, RasterOp {
    private AffineTransform xform;
    RenderingHints hints;

    /**
     * Nearest-neighbor interpolation type.
     */
    public static final int TYPE_NEAREST_NEIGHBOR = 1;
    /**
     * Bilinear interpolation type.
     */
    public static final int TYPE_BILINEAR = 2;
    /**
     * Bicubic interpolation type.
     */
    private static final int TYPE_BICUBIC = 3;

    int interpolationType = TYPE_NEAREST_NEIGHBOR;

    /**
     * Constructs an <CODE>AffineTransformOp</CODE> given an affine transform.
     * The interpolation type is determined from the 
     * <CODE>RenderingHints</CODE> object.  If the interpolation hint is 
     * defined, it will be used. Otherwise, if the rendering quality hint is        
     * defined, the interpolation type is determined from its value.  If no 
     * hints are specified (<CODE>hints</CODE> is null),
     * the interpolation type is {@link #TYPE_NEAREST_NEIGHBOR 
     * TYPE_NEAREST_NEIGHBOR}.
     *
     * @param xform The <CODE>AffineTransform</CODE> to use for the
     * operation.
     *
     * @param hints The <CODE>RenderingHints</CODE> object used to specify
     * the interpolation type for the operation. 
     *
     * @throws ImagingOpException if the transform is non-invertible.
     * @see java.awt.RenderingHints#KEY_INTERPOLATION
     * @see java.awt.RenderingHints#KEY_RENDERING
     */
    public AffineTransformOp(AffineTransform xform, RenderingHints hints){
        validateTransform(xform);
        this.xform = (AffineTransform) xform.clone();
        this.hints = hints;

        if (hints != null) {
            Object value = hints.get(hints.KEY_INTERPOLATION);
            if (value == null) {
                value = hints.get(hints.KEY_RENDERING);
                if (value == hints.VALUE_RENDER_SPEED) {
                    interpolationType = TYPE_NEAREST_NEIGHBOR;
                }
                else if (value == hints.VALUE_RENDER_QUALITY) {
                    interpolationType = TYPE_BILINEAR;
                }
            }
            else if (value == hints.VALUE_INTERPOLATION_NEAREST_NEIGHBOR) {
                interpolationType = TYPE_NEAREST_NEIGHBOR;
            }
            else if (value == hints.VALUE_INTERPOLATION_BILINEAR) {
                interpolationType = TYPE_BILINEAR;
            }
            else if (value == hints.VALUE_INTERPOLATION_BICUBIC) {
                interpolationType = TYPE_BICUBIC;
            }
        }
        else {
            interpolationType = TYPE_NEAREST_NEIGHBOR;
        }
    }

    /**
     * Constructs an <CODE>AffineTransformOp</CODE> given an affine transform 
     * and the interpolation type.
     * 
     * @param xform The <CODE>AffineTransform</CODE> to use for the operation.
     * @param interpolationType One of the integer
     * interpolation type constants defined by this class: 
     * {@link #TYPE_NEAREST_NEIGHBOR TYPE_NEAREST_NEIGHBOR}, 
     * {@link #TYPE_BILINEAR TYPE_BILINEAR}. 
     * @throws ImagingOpException if the transform is non-invertible.
     */
    public AffineTransformOp(AffineTransform xform, int interpolationType) {
        validateTransform(xform);
        this.xform = (AffineTransform)xform.clone();
        switch(interpolationType) {
            case TYPE_NEAREST_NEIGHBOR:
            case TYPE_BILINEAR:
            case TYPE_BICUBIC:
                break;
        default:
            throw new IllegalArgumentException("Unknown interpolation type: "+
                                               interpolationType);
        }
        this.interpolationType = interpolationType;
    }

    /**
     * Returns the interpolation type used by this op.
     * @return the interpolation type.
     * @see #TYPE_NEAREST_NEIGHBOR
     * @see #TYPE_BILINEAR
     */
    public final int getInterpolationType() {
        return interpolationType;
    }

    /**
     * Transforms the source <CODE>BufferedImage</CODE> and stores the results 
     * in the destination <CODE>BufferedImage</CODE>.  
     * If the color models for the two images do not match, a color
     * conversion into the destination color model is performed.
     * If the destination image is null,
     * a <CODE>BufferedImage</CODE> is created with the source 
     * <CODE>ColorModel</CODE>.
     * <p>
     * The coordinates of the rectangle returned by 
     * <code>getBounds2D(BufferedImage)</code>
     * are not necessarily the same as the coordinates of the 
     * <code>BufferedImage</code> returned by this method.  If the
     * upper-left corner coordinates of the rectangle are 
     * negative then this part of the rectangle is not drawn.  If the
     * upper-left corner coordinates of the  rectangle are positive 
     * then the filtered image is drawn at that position in the
     * destination <code>BufferedImage</code>.
     * <p> 
     * An <CODE>IllegalArgumentException</CODE> is thrown if the source is
     * the same as the destination.
     *
     * @param src The <CODE>BufferedImage</CODE> to transform.
     * @param dst The <CODE>BufferedImage</CODE> in which to store the results 
     * of the transformation.
     *
     * @return The filtered <CODE>BufferedImage</CODE>.
     * @throws IllegalArgumentException if <code>src</code> and 
     *         <code>dst</code> are the same
     * @throws ImagingOpException if the image cannot be transformed
     *         because of a data-processing error that might be 
     *         caused by an invalid image format, tile format, or
     *         image-processing operation, or any other unsupported 
     *         operation.
     */
    public final BufferedImage filter(BufferedImage src, BufferedImage dst) {
        
        if (src == null) {
            throw new NullPointerException("src image is null");
        }
        if (src == dst) {
            throw new IllegalArgumentException("src image cannot be the "+
                                               "same as the dst image");
        }

        boolean needToConvert = false;
        ColorModel srcCM = src.getColorModel();
        ColorModel dstCM;
        BufferedImage origDst = dst;
        
        if (dst == null) {
            dst = createCompatibleDestImage(src, null);
            dstCM = srcCM;
            origDst = dst;
        }
        else {
            dstCM = dst.getColorModel();
            if (srcCM.getColorSpace().getType() !=
                dstCM.getColorSpace().getType())
            {
                int type = xform.getType();
                boolean needTrans = ((type&
                                      (xform.TYPE_MASK_ROTATION|
                                       xform.TYPE_GENERAL_TRANSFORM))
                                     != 0);
                if (! needTrans && type != xform.TYPE_TRANSLATION && type != xform.TYPE_IDENTITY)
                {
                    double[] mtx = new double[4];
                    xform.getMatrix(mtx);
                    // Check out the matrix.  A non-integral scale will force ARGB
                    // since the edge conditions can't be guaranteed.
                    needTrans = (mtx[0] != (int)mtx[0] || mtx[3] != (int)mtx[3]);
                }
                
                if (needTrans &&
                    srcCM.getTransparency() == Transparency.OPAQUE)
                {
                    // Need to convert first
                    ColorConvertOp ccop = new ColorConvertOp(hints);
                    BufferedImage tmpSrc = null;
                    int sw = src.getWidth();
                    int sh = src.getHeight();
                    if (dstCM.getTransparency() == Transparency.OPAQUE) {
                        tmpSrc = new BufferedImage(sw, sh,
                                                  BufferedImage.TYPE_INT_ARGB);
                    }
                    else {
                        WritableRaster r =
                            dstCM.createCompatibleWritableRaster(sw, sh);
                        tmpSrc = new BufferedImage(dstCM, r,
                                                  dstCM.isAlphaPremultiplied(),
                                                  null);
                    }
                    src = ccop.filter(src, tmpSrc);
                }
                else {
                    needToConvert = true;
                    dst = createCompatibleDestImage(src, null);
                }
            }

        }
        
        if (interpolationType != TYPE_NEAREST_NEIGHBOR &&
            dst.getColorModel() instanceof IndexColorModel) {
            dst = new BufferedImage(dst.getWidth(), dst.getHeight(),
                                    BufferedImage.TYPE_INT_ARGB);
        }
        if (ImagingLib.filter(this, src, dst) == null) {
            throw new ImagingOpException ("Unable to transform src image");
        }
        
        if (needToConvert) {
            ColorConvertOp ccop = new ColorConvertOp(hints);
            ccop.filter(dst, origDst);
        }
        else if (origDst != dst) {
            java.awt.Graphics2D g = origDst.createGraphics();