http://xmlgraphics.apache.org/batik/batik-bridge/: Batik bridge (Apache Software Foundation) 
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   this work for additional information regarding copyright ownership.
   The ASF licenses this file to You under the Apache License, Version 2.0
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package org.apache.batik.bridge;

import java.awt.geom.AffineTransform;
import java.awt.geom.Rectangle2D;
import java.util.Map;

import org.apache.batik.dom.util.XLinkSupport;
import org.apache.batik.ext.awt.image.PadMode;
import org.apache.batik.ext.awt.image.renderable.AffineRable8Bit;
import org.apache.batik.ext.awt.image.renderable.Filter;
import org.apache.batik.ext.awt.image.renderable.PadRable8Bit;
import org.apache.batik.ext.awt.image.spi.ImageTagRegistry;
import org.apache.batik.gvt.GraphicsNode;
import org.apache.batik.util.ParsedURL;
import org.w3c.dom.Document;
import org.w3c.dom.Element;


Bridge class for the <feImage> element.

Author:Thierry Kormann
Version:$Id: SVGFeImageElementBridge.java 1805408 2017-08-18 12:21:52Z ssteiner $
/**
 * Bridge class for the &lt;feImage&gt; element.
 *
 * @author <a href="mailto:tkormann@apache.org">Thierry Kormann</a>
 * @version $Id: SVGFeImageElementBridge.java 1805408 2017-08-18 12:21:52Z ssteiner $
 */
public class SVGFeImageElementBridge
    extends AbstractSVGFilterPrimitiveElementBridge {

    
Constructs a new bridge for the <feImage> element.

/**
     * Constructs a new bridge for the &lt;feImage&gt; element.
     */
    public SVGFeImageElementBridge() {}

    
Returns 'feImage'.

/**
     * Returns 'feImage'.
     */
    public String getLocalName() {
        return SVG_FE_IMAGE_TAG;
    }

    
Creates a Filter primitive according to the specified
parameters.

Params:
  • ctx – the bridge context to use
  • filterElement – the element that defines a filter
  • filteredElement – the element that references the filter
  • filteredNode – the graphics node to filter
  • inputFilter – the Filter that represents the current
       filter input if the filter chain.
  • filterRegion – the filter area defined for the filter chain
       the new node will be part of.
  • filterMap – a map where the mediator can map a name to the
       Filter it creates. Other FilterBridges
       can then access a filter node from the filterMap if they
       know its name.
/**
     * Creates a <code>Filter</code> primitive according to the specified
     * parameters.
     *
     * @param ctx the bridge context to use
     * @param filterElement the element that defines a filter
     * @param filteredElement the element that references the filter
     * @param filteredNode the graphics node to filter
     *
     * @param inputFilter the <code>Filter</code> that represents the current
     *        filter input if the filter chain.
     * @param filterRegion the filter area defined for the filter chain
     *        the new node will be part of.
     * @param filterMap a map where the mediator can map a name to the
     *        <code>Filter</code> it creates. Other <code>FilterBridge</code>s
     *        can then access a filter node from the filterMap if they
     *        know its name.
     */
    public Filter createFilter(BridgeContext ctx,
                               Element filterElement,
                               Element filteredElement,
                               GraphicsNode filteredNode,
                               Filter inputFilter,
                               Rectangle2D filterRegion,
                               Map filterMap) {

        // 'xlink:href' attribute
        String uriStr = XLinkSupport.getXLinkHref(filterElement);
        if (uriStr.length() == 0) {
            throw new BridgeException(ctx, filterElement, ERR_ATTRIBUTE_MISSING,
                                      new Object[] {"xlink:href"});
        }

        //
        // According the the SVG specification, feImage behaves like
        // <image> if it references an SVG document or a raster image
        // and it behaves like a <use> if it references a document
        // fragment.
        //
        // To provide this behavior, depending on whether the uri
        // contains a fragment identifier, we create either an
        // <image> or a <use> element and request the corresponding
        // bridges to build the corresponding GraphicsNode for us.
        //
        // Then, we take care of the possible transformation needed
        // from objectBoundingBox space to user space.
        //

        Document document = filterElement.getOwnerDocument();
        boolean isUse = uriStr.indexOf('#') != -1;
        Element contentElement = null;
        if (isUse) {
            contentElement = document.createElementNS(SVG_NAMESPACE_URI,
                                                      SVG_USE_TAG);
        } else {
            contentElement = document.createElementNS(SVG_NAMESPACE_URI,
                                                      SVG_IMAGE_TAG);
        }


        contentElement.setAttributeNS(XLINK_NAMESPACE_URI,
                                      XLINK_HREF_QNAME,
                                      uriStr);

        Element proxyElement = document.createElementNS(SVG_NAMESPACE_URI,
                                                        SVG_G_TAG);
        proxyElement.appendChild(contentElement);

        // feImage's default region is that of the filter chain.
        Rectangle2D defaultRegion = filterRegion;
        Element filterDefElement = (Element)(filterElement.getParentNode());

        Rectangle2D primitiveRegion =
            SVGUtilities.getBaseFilterPrimitiveRegion(filterElement,
                                                      filteredElement,
                                                      filteredNode,
                                                      defaultRegion,
                                                      ctx);

        // System.err.println(">>>>>>>> primitiveRegion : " + primitiveRegion);

        contentElement.setAttributeNS(null, SVG_X_ATTRIBUTE,      String.valueOf( primitiveRegion.getX() ) );
        contentElement.setAttributeNS(null, SVG_Y_ATTRIBUTE,      String.valueOf( primitiveRegion.getY() ) );
        contentElement.setAttributeNS(null, SVG_WIDTH_ATTRIBUTE,  String.valueOf( primitiveRegion.getWidth() ) );
        contentElement.setAttributeNS(null, SVG_HEIGHT_ATTRIBUTE, String.valueOf( primitiveRegion.getHeight() ) );


        GraphicsNode node = ctx.getGVTBuilder().build(ctx, proxyElement);
        Filter filter = node.getGraphicsNodeRable(true);

        // 'primitiveUnits' attribute - default is userSpaceOnUse
        short coordSystemType;
        String s = SVGUtilities.getChainableAttributeNS
            (filterDefElement, null, SVG_PRIMITIVE_UNITS_ATTRIBUTE, ctx);
        if (s.length() == 0) {
            coordSystemType = SVGUtilities.USER_SPACE_ON_USE;
        } else {
            coordSystemType = SVGUtilities.parseCoordinateSystem
                (filterDefElement, SVG_PRIMITIVE_UNITS_ATTRIBUTE, s, ctx);
        }

        // Compute the transform from object bounding box to user
        // space if needed.
        AffineTransform at = new AffineTransform();
        if (coordSystemType == SVGUtilities.OBJECT_BOUNDING_BOX) {
            at = SVGUtilities.toObjectBBox(at, filteredNode);
        }
        filter = new AffineRable8Bit(filter, at);

        // handle the 'color-interpolation-filters' property
        handleColorInterpolationFilters(filter, filterElement);

        // get filter primitive chain region
        Rectangle2D primitiveRegionUserSpace
            = SVGUtilities.convertFilterPrimitiveRegion(filterElement,
                                                        filteredElement,
                                                        filteredNode,
                                                        defaultRegion,
                                                        filterRegion,
                                                        ctx);
        filter = new PadRable8Bit(filter, primitiveRegionUserSpace,
                                  PadMode.ZERO_PAD);

        // update the filter Map
        updateFilterMap(filterElement, filter, filterMap);

        return filter;
    }

    
Returns a Filter that represents a svg document or element as an image.

Params:
  • ctx – the bridge context
  • primitiveRegion – the primitive region
  • refElement – the referenced element
  • toBBoxNeeded – true if there is a need to transform to ObjectBoundingBox
       space
  • filterElement – parent filter element
  • filteredNode – node to which the filter applies
/**
     * Returns a Filter that represents a svg document or element as an image.
     *
     * @param ctx the bridge context
     * @param primitiveRegion the primitive region
     * @param refElement the referenced element
     * @param toBBoxNeeded true if there is a need to transform to ObjectBoundingBox
     *        space
     * @param filterElement parent filter element
     * @param filteredNode node to which the filter applies
     */
    protected static Filter createSVGFeImage(BridgeContext ctx,
                                             Rectangle2D primitiveRegion,
                                             Element refElement,
                                             boolean toBBoxNeeded,
                                             Element filterElement,
                                             GraphicsNode filteredNode) {

        //
        // <!> FIX ME
        // Unresolved issue on the feImage behavior when referencing an
        // image (PNG, JPEG or SVG image).
        // VH & TK, 03/08/2002
        // Furthermore, for feImage referencing doc fragment, should act
        // like a <use>, i.e., CSS cascading and the whole zing bang.
        //
        GraphicsNode node = ctx.getGVTBuilder().build(ctx, refElement);
        Filter filter = node.getGraphicsNodeRable(true);

        AffineTransform at = new AffineTransform();

        if (toBBoxNeeded){
            // 'primitiveUnits' attribute - default is userSpaceOnUse
            short coordSystemType;
            Element filterDefElement = (Element)(filterElement.getParentNode());
            String s = SVGUtilities.getChainableAttributeNS
                (filterDefElement, null, SVG_PRIMITIVE_UNITS_ATTRIBUTE, ctx);
            if (s.length() == 0) {
                coordSystemType = SVGUtilities.USER_SPACE_ON_USE;
            } else {
                coordSystemType = SVGUtilities.parseCoordinateSystem
                    (filterDefElement, SVG_PRIMITIVE_UNITS_ATTRIBUTE, s, ctx);
            }

            if (coordSystemType == SVGUtilities.OBJECT_BOUNDING_BOX) {
                at = SVGUtilities.toObjectBBox(at, filteredNode);
            }

            Rectangle2D bounds = filteredNode.getGeometryBounds();
            at.preConcatenate(AffineTransform.getTranslateInstance
                              (primitiveRegion.getX() - bounds.getX(),
                               primitiveRegion.getY() - bounds.getY()));

        } else {

            // Need to translate the image to the x, y coordinate to
            // have the same behavior as the <use> element
            at.translate(primitiveRegion.getX(), primitiveRegion.getY());
        }

        return new AffineRable8Bit(filter, at);
    }

    
Returns a Filter that represents an raster image (JPG or PNG).

Params:
  • ctx – the bridge context
  • primitiveRegion – the primitive region
  • purl – the url of the image
/**
     * Returns a Filter that represents an raster image (JPG or PNG).
     *
     * @param ctx the bridge context
     * @param primitiveRegion the primitive region
     * @param purl the url of the image
     */
    protected static Filter createRasterFeImage(BridgeContext ctx,
                                                Rectangle2D   primitiveRegion,
                                                ParsedURL     purl) {

        // Need to fit the raster image to the filter region so that
        // we have the same behavior as raster images in the <image> element.
        Filter filter = ImageTagRegistry.getRegistry().readURL(purl);

        Rectangle2D bounds = filter.getBounds2D();
        AffineTransform scale = new AffineTransform();
        scale.translate(primitiveRegion.getX(), primitiveRegion.getY());
        scale.scale(primitiveRegion.getWidth()/(bounds.getWidth()-1),
                    primitiveRegion.getHeight()/(bounds.getHeight()-1));
        scale.translate(-bounds.getX(), -bounds.getY());

        return new AffineRable8Bit(filter, scale);
    }
}