sources/org/apache/batik/extension/svg/BatikHistogramNormalizationElementBridge.java

/*

   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.extension.svg;

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

import org.apache.batik.bridge.AbstractSVGFilterPrimitiveElementBridge;
import org.apache.batik.bridge.Bridge;
import org.apache.batik.bridge.BridgeContext;
import org.apache.batik.bridge.BridgeException;
import org.apache.batik.bridge.SVGUtilities;
import org.apache.batik.ext.awt.image.PadMode;
import org.apache.batik.ext.awt.image.renderable.Filter;
import org.apache.batik.ext.awt.image.renderable.PadRable8Bit;
import org.apache.batik.gvt.GraphicsNode;
import org.w3c.dom.Element;

/**
 * Bridge class for a histogram normalization element.
 *
 * @author <a href="mailto:thomas.deweese@kodak.com">Thomas Deweese</a>
 * @version $Id$
 */
public class BatikHistogramNormalizationElementBridge
    extends AbstractSVGFilterPrimitiveElementBridge
    implements BatikExtConstants {

    /**
     * Constructs a new bridge for the &lt;histogramNormalization> element.
     */
    public BatikHistogramNormalizationElementBridge() { /* nothing */ }

    /**
     * Returns the SVG namespace URI.
     */
    public String getNamespaceURI() {
        return BATIK_EXT_NAMESPACE_URI;
    }

    /**
     * Returns 'histogramNormalization'.
     */
    public String getLocalName() {
        return BATIK_EXT_HISTOGRAM_NORMALIZATION_TAG;
    }

    /**
     * Returns a new instance of this bridge.
     */
    public Bridge getInstance() {
        return new BatikHistogramNormalizationElementBridge();
    }

    /**
     * Creates a <tt>Filter</tt> 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 <tt>Filter</tt> 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
     *        <tt>Filter</tt> it creates. Other <tt>FilterBridge</tt>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) {

        // 'in' attribute
        Filter in = getIn(filterElement,
                          filteredElement,
                          filteredNode,
                          inputFilter,
                          filterMap,
                          ctx);
        if (in == null) {
            return null; // disable the filter
        }

        // The default region is the union of the input sources
        // regions unless 'in' is 'SourceGraphic' in which case the
        // default region is the filterChain's region
        Filter sourceGraphics = (Filter)filterMap.get(SVG_SOURCE_GRAPHIC_VALUE);
        Rectangle2D defaultRegion;
        if (in == sourceGraphics) {
            defaultRegion = filterRegion;
        } else {
            defaultRegion = in.getBounds2D();
        }

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

        float trim = 1;
        String s = filterElement.getAttributeNS
            (null, BATIK_EXT_TRIM_ATTRIBUTE);

        if (s.length() != 0) {
            try {
                trim = SVGUtilities.convertSVGNumber(s);
            } catch (NumberFormatException nfEx ) {
                throw new BridgeException
                    (ctx, filterElement, nfEx, ERR_ATTRIBUTE_VALUE_MALFORMED,
                     new Object[] {BATIK_EXT_TRIM_ATTRIBUTE, s});
            }
        }

        if (trim < 0) trim =0;
        else if (trim > 100) trim=100;

        Filter filter = in;
        filter = new BatikHistogramNormalizationFilter8Bit(filter, trim/100);

        filter = new PadRable8Bit(filter, primitiveRegion, PadMode.ZERO_PAD);

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

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

        return filter;
    }

    /**
     * Stolen from AbstractSVGFilterPrimitiveElementBridge.
     * Converts on the specified filter primitive element, the specified
     * attribute that represents an integer and with the specified
     * default value.
     *
     * @param filterElement the filter primitive element
     * @param attrName the name of the attribute
     * @param defaultValue the default value of the attribute
     * @param ctx the BridgeContext to use for error information
     */
    protected static int convertSides(Element filterElement,
                                      String attrName,
                                      int defaultValue,
                                      BridgeContext ctx) {
        String s = filterElement.getAttributeNS(null, attrName);
        if (s.length() == 0) {
            return defaultValue;
        } else {
            int ret = 0;
            try {
                ret = SVGUtilities.convertSVGInteger(s);
            } catch (NumberFormatException nfEx ) {
                throw new BridgeException
                    (ctx, filterElement, nfEx, ERR_ATTRIBUTE_VALUE_MALFORMED,
                     new Object[] {attrName, s});
            }

            if (ret <3)
                throw new BridgeException
                    (ctx, filterElement, ERR_ATTRIBUTE_VALUE_MALFORMED,
                     new Object[] {attrName, s});
            return ret;
        }
    }
}