affinetransformop.java

JAVA基本类源代码,大家可以学习学习!

	    try {
                g.setComposite(AlphaComposite.Src);
	        g.drawImage(dst, 0, 0, null);
	    } finally {
	        g.dispose();
	    }
        }
        
        return origDst;
    }

    /**
     * Transforms the source <CODE>Raster</CODE> and stores the results in
     * the destination <CODE>Raster</CODE>.  This operation performs the
     * transform band by band.
     * <p>
     * If the destination <CODE>Raster</CODE> is null, a new 
     * <CODE>Raster</CODE> is created.
     * An <CODE>IllegalArgumentException</CODE> may be thrown if the source is
     * the same as the destination or if the number of bands in
     * the source is not equal to the number of bands in the
     * destination.
     * <p>
     * The coordinates of the rectangle returned by 
     * <code>getBounds2D(Raster)</code>
     * are not necessarily the same as the coordinates of the
     * <code>WritableRaster</code> returned by this method.  If the
     * upper-left corner coordinates of rectangle are negative then
     * this part of the rectangle is not drawn.  If the coordinates 
     * of the rectangle are positive then the filtered image is drawn at
     * that position in the destination <code>Raster</code>.
     * <p>
     * @param src The <CODE>Raster</CODE> to transform.
     * @param dst The <CODE>Raster</CODE> in which to store the results of the 
     * transformation.
     *
     * @return The transformed <CODE>Raster</CODE>.
     *
     * @throws ImagingOpException if the raster 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 WritableRaster filter(Raster src, WritableRaster dst) {
        if (src == null) {
            throw new NullPointerException("src image is null");
        }
        if (dst == null) {
            dst = createCompatibleDestRaster(src);
        }
        if (src == dst) {
            throw new IllegalArgumentException("src image cannot be the "+
                                               "same as the dst image");
        }
        if (src.getNumBands() != dst.getNumBands()) {
            throw new IllegalArgumentException("Number of src bands ("+
                                               src.getNumBands()+
                                               ") does not match number of "+
                                               " dst bands ("+
                                               dst.getNumBands()+")");
        }

        if (ImagingLib.filter(this, src, dst) == null) {
            throw new ImagingOpException ("Unable to transform src image");
        }
        return dst;
    }

    /**
     * Returns the bounding box of the transformed destination.  The
     * rectangle returned is the actual bounding box of the 
     * transformed points.  The coordinates of the upper-left corner
     * of the returned rectangle might not be (0,&nbsp;0).
     *
     * @param src The <CODE>BufferedImage</CODE> to be transformed.
     *
     * @return The <CODE>Rectangle2D</CODE> representing the destination's
     * bounding box.
     */
    public final Rectangle2D getBounds2D (BufferedImage src) {
        return getBounds2D(src.getRaster());
    }

    /**
     * Returns the bounding box of the transformed destination.  The
     * rectangle returned will be the actual bounding box of the
     * transformed points.  The coordinates of the upper-left corner
     * of the returned rectangle might not be (0,&nbsp;0).
     *
     * @param src The <CODE>Raster</CODE> to be transformed.
     *
     * @return The <CODE>Rectangle2D</CODE> representing the destination's
     * bounding box.
     */
    public final Rectangle2D getBounds2D (Raster src) {
        int w = src.getWidth();
        int h = src.getHeight();

        // Get the bounding box of the src and transform the corners
        float[] pts = {0, 0, w, 0, w, h, 0, h};
        xform.transform(pts, 0, pts, 0, 4);

        // Get the min, max of the dst
        float fmaxX = pts[0];
        float fmaxY = pts[1];
        float fminX = pts[0];
        float fminY = pts[1];
        int maxX;
        int maxY;
        for (int i=2; i < 8; i+=2) {
            if (pts[i] > fmaxX) {
                fmaxX = pts[i];
            }
            else if (pts[i] < fminX) {
                fminX = pts[i];
            }
            if (pts[i+1] > fmaxY) {
                fmaxY = pts[i+1];
            }
            else if (pts[i+1] < fminY) {
                fminY = pts[i+1];
            }
        }

        return new Rectangle2D.Float(fminX, fminY, fmaxX-fminX, fmaxY-fminY);
    }

    /**
     * Creates a zeroed destination image with the correct size and number of
     * bands.  A <CODE>RasterFormatException</CODE> may be thrown if the 
     * transformed width or height is equal to 0.  
     * <p>
     * If <CODE>destCM</CODE> is null,
     * an appropriate <CODE>ColorModel</CODE> is used; this 
     * <CODE>ColorModel</CODE> may have
     * an alpha channel even if the source <CODE>ColorModel</CODE> is opaque.
     *
     * @param src  The <CODE>BufferedImage</CODE> to be transformed.
     * @param destCM  <CODE>ColorModel</CODE> of the destination.  If null,
     * an appropriate <CODE>ColorModel</CODE> is used.  
     *
     * @return The zeroed destination image.
     */
    public BufferedImage createCompatibleDestImage (BufferedImage src,
                                                    ColorModel destCM) {
        BufferedImage image;
        Rectangle r = getBounds2D(src).getBounds();

        // If r.x (or r.y) is < 0, then we want to only create an image 
        // that is in the positive range.
        // If r.x (or r.y) is > 0, then we need to create an image that
        // includes the translation.
        int w = r.x + r.width;
        int h = r.y + r.height;
        if (w <= 0) {
            throw new RasterFormatException("Transformed width ("+w+
                                            ") is less than or equal to 0.");
        }
        if (h <= 0) {
            throw new RasterFormatException("Transformed height ("+h+
                                            ") is less than or equal to 0.");
        }
        
        if (destCM == null) {
            ColorModel cm = src.getColorModel();
            if (interpolationType != TYPE_NEAREST_NEIGHBOR &&
                (cm instanceof IndexColorModel ||
                 cm.getTransparency() == Transparency.OPAQUE))
            {
                image = new BufferedImage(w, h,
                                          BufferedImage.TYPE_INT_ARGB);
            }
            else {
                image = new BufferedImage(cm,
                          src.getRaster().createCompatibleWritableRaster(w,h),
                          cm.isAlphaPremultiplied(), null);
            }
        }
        else {
            image = new BufferedImage(destCM,
                                    destCM.createCompatibleWritableRaster(w,h),
                                    destCM.isAlphaPremultiplied(), null);
        }

        return image;
    }

    /**
     * Creates a zeroed destination <CODE>Raster</CODE> with the correct size 
     * and number of bands.  A <CODE>RasterFormatException</CODE> may be thrown 
     * if the transformed width or height is equal to 0.
     *
     * @param src The <CODE>Raster</CODE> to be transformed.
     *
     * @return The zeroed destination <CODE>Raster</CODE>.
     */
    public WritableRaster createCompatibleDestRaster (Raster src) {
        Rectangle2D r = getBounds2D(src);

        return src.createCompatibleWritableRaster((int)r.getX(),
                                                  (int)r.getY(),
                                                  (int)r.getWidth(),
                                                  (int)r.getHeight());
    }

    /**
     * Returns the location of the corresponding destination point given a
     * point in the source.  If <CODE>dstPt</CODE> is specified, it
     * is used to hold the return value.
     *
     * @param srcPt The <code>Point2D</code> that represents the source
     *              point.
     * @param dstPt The <CODE>Point2D</CODE> in which to store the result.
     *
     * @return The <CODE>Point2D</CODE> in the destination that corresponds to 
     * the specified point in the source.
     */
    public final Point2D getPoint2D (Point2D srcPt, Point2D dstPt) {
        return xform.transform (srcPt, dstPt);
    }

    /**
     * Returns the affine transform used by this transform operation.
     *
     * @return The <CODE>AffineTransform</CODE> associated with this op. 
     */
    public final AffineTransform getTransform() {
        return (AffineTransform) xform.clone();
    }

    /**
     * Returns the rendering hints used by this transform operation.
     *
     * @return The <CODE>RenderingHints</CODE> object associated with this op. 
     */
    public final RenderingHints getRenderingHints() {
        if (hints == null) {
            Object val;
            switch(interpolationType) {
            case TYPE_NEAREST_NEIGHBOR:
                val = RenderingHints.VALUE_INTERPOLATION_NEAREST_NEIGHBOR;
                break;
            case TYPE_BILINEAR:
                val = RenderingHints.VALUE_INTERPOLATION_BILINEAR;
                break;
            case TYPE_BICUBIC:
                val = RenderingHints.VALUE_INTERPOLATION_BICUBIC;
                break;
            default:
                // Should never get here 
                throw new InternalError("Unknown interpolation type "+
                                         interpolationType);

            }
            hints = new RenderingHints(RenderingHints.KEY_INTERPOLATION, val);
        }

        return hints;
    }

    // We need to be able to invert the transform if we want to
    // transform the image.  If the determinant of the matrix is 0,
    // then we can't invert the transform.
    void validateTransform(AffineTransform xform) {
        if (Math.abs(xform.getDeterminant()) <= Double.MIN_VALUE) {
            throw new ImagingOpException("Unable to invert transform "+xform);
        }
    }
}