batik-bridge/src/main/java/org/apache/batik/bridge/ViewBox.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.bridge;

import java.awt.geom.AffineTransform;
import java.util.StringTokenizer;

import org.apache.batik.anim.dom.SVGOMAnimatedRect;
import org.apache.batik.dom.svg.LiveAttributeException;
import org.apache.batik.parser.AWTTransformProducer;
import org.apache.batik.parser.FragmentIdentifierHandler;
import org.apache.batik.parser.FragmentIdentifierParser;
import org.apache.batik.parser.ParseException;
import org.apache.batik.parser.PreserveAspectRatioParser;
import org.apache.batik.dom.util.DOMUtilities;
import org.apache.batik.util.SVGConstants;

import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.svg.SVGAnimatedPreserveAspectRatio;
import org.w3c.dom.svg.SVGAnimatedRect;
import org.w3c.dom.svg.SVGPreserveAspectRatio;
import org.w3c.dom.svg.SVGRect;

/**
 * This class provides convenient methods to handle viewport.
 *
 * @author <a href="mailto:tkormann@apache.org">Thierry Kormann</a>
 * @version $Id$
 */
public abstract class ViewBox implements SVGConstants, ErrorConstants {

    /**
     * No instance of this class is required.
     */
    protected ViewBox() { }

    /**
     * Parses the specified reference (from a URI) and returns the appropriate
     * transform.
     *
     * @param ref the reference of the URI that may specify additional attribute
     *            values such as the viewBox, preserveAspectRatio or a transform
     * @param e the element interested in its view transform
     * @param w the width of the effective viewport
     * @param h The height of the effective viewport
     * @param ctx The BridgeContext to use for error information
     * @exception BridgeException if an error occured while computing the
     *            preserveAspectRatio transform
     */
    public static AffineTransform getViewTransform(String ref,
                                                   Element e,
                                                   float w,
                                                   float h,
                                                   BridgeContext ctx) {

        // no reference has been specified, no extra viewBox is defined
        if (ref == null || ref.length() == 0) {
            return getPreserveAspectRatioTransform(e, w, h, ctx);
        }

        ViewHandler vh = new ViewHandler();
        FragmentIdentifierParser p = new FragmentIdentifierParser();
        p.setFragmentIdentifierHandler(vh);
        p.parse(ref);

        // Determine the 'view' element that ref refers to.
        Element viewElement = e;
        if (vh.hasId) {
            Document document = e.getOwnerDocument();
            viewElement = document.getElementById(vh.id);
        }
        if (viewElement == null) {
            throw new BridgeException(ctx, e, ERR_URI_MALFORMED,
                                      new Object[] {ref});
        }

        Element ancestorSVG = getClosestAncestorSVGElement(e);
        if (!(viewElement.getNamespaceURI().equals(SVG_NAMESPACE_URI)
              && viewElement.getLocalName().equals(SVG_VIEW_TAG))) {
            viewElement = ancestorSVG;
        }

        // 'viewBox'
        float[] vb;
        if (vh.hasViewBox) {
            vb = vh.viewBox;
        } else {
            Element elt;
            if (DOMUtilities.isAttributeSpecifiedNS
                    (viewElement, null, SVG_VIEW_BOX_ATTRIBUTE)) {
                elt = viewElement;
            } else {
                elt = ancestorSVG;
            }
            String viewBoxStr = elt.getAttributeNS(null, SVG_VIEW_BOX_ATTRIBUTE);
            vb = parseViewBoxAttribute(elt, viewBoxStr, ctx);
        }

        // 'preserveAspectRatio'
        short align;
        boolean meet;
        if (vh.hasPreserveAspectRatio) {
            align = vh.align;
            meet = vh.meet;
        } else {
            Element elt;
            if (DOMUtilities.isAttributeSpecifiedNS
                    (viewElement, null, SVG_PRESERVE_ASPECT_RATIO_ATTRIBUTE)) {
                elt = viewElement;
            } else {
                elt = ancestorSVG;
            }
            String aspectRatio =
                elt.getAttributeNS(null, SVG_PRESERVE_ASPECT_RATIO_ATTRIBUTE);
            PreserveAspectRatioParser pp = new PreserveAspectRatioParser();
            ViewHandler ph = new ViewHandler();
            pp.setPreserveAspectRatioHandler(ph);
            try {
                pp.parse(aspectRatio);
            } catch (ParseException pEx) {
                throw new BridgeException
                    (ctx, elt, pEx, ERR_ATTRIBUTE_VALUE_MALFORMED,
                     new Object[] {SVG_PRESERVE_ASPECT_RATIO_ATTRIBUTE,
                                       aspectRatio, pEx });
            }
            align = ph.align;
            meet = ph.meet;
        }

        // the additional transform that may appear on the URI
        AffineTransform transform
            = getPreserveAspectRatioTransform(vb, align, meet, w, h);
        if (vh.hasTransform) {
            transform.concatenate(vh.getAffineTransform());
        }
        return transform;
    }

    /**
     * Returns the closest svg element ancestor of the specified element.
     *
     * @param e the element on which to start the svg element lookup
     */
    private static Element getClosestAncestorSVGElement(Element e) {
        for  (Node n = e;
              n != null && n.getNodeType() == Node.ELEMENT_NODE;
              n = n.getParentNode()) {
            Element tmp = (Element)n;
            if (tmp.getNamespaceURI().equals(SVG_NAMESPACE_URI)
                && tmp.getLocalName().equals(SVG_SVG_TAG)) {
                return tmp;
            }
        }
        return null;
    }

    /**
     * Returns the transformation matrix to apply to initalize a viewport or
     * null if the specified viewBox disables the rendering of the element.
     *
     * @deprecated Replaced by {@link
     *     #getPreserveAspectRatioTransform(Element,float,float,BridgeContext)},
     *     which has more accurate error reporting.
     * @param e the element with a viewbox
     * @param w the width of the effective viewport
     * @param h The height of the effective viewport
     */
    public static AffineTransform getPreserveAspectRatioTransform(Element e,
                                                                  float w,
                                                                  float h) {
        return getPreserveAspectRatioTransform(e, w, h, null);
    }

    /**
     * Returns the transformation matrix to apply to initalize a viewport or
     * null if the specified viewBox disables the rendering of the element.
     *
     * @param e the element with a viewbox
     * @param w the width of the effective viewport
     * @param h The height of the effective viewport
     * @param ctx The BridgeContext to use for error information
     */
    public static AffineTransform getPreserveAspectRatioTransform
            (Element e, float w, float h, BridgeContext ctx) {
        String viewBox
            = e.getAttributeNS(null, SVG_VIEW_BOX_ATTRIBUTE);

        String aspectRatio
            = e.getAttributeNS(null, SVG_PRESERVE_ASPECT_RATIO_ATTRIBUTE);

        return getPreserveAspectRatioTransform(e, viewBox, aspectRatio, w, h,
                                               ctx);
    }

    /**
     * Returns the transformation matrix to apply to initalize a viewport or
     * null if the specified viewBox disables the rendering of the element.
     *
     * @param e the element with a viewbox
     * @param viewBox the viewBox definition
     * @param w the width of the effective viewport
     * @param h The height of the effective viewport
     * @param ctx The BridgeContext to use for error information
     */
    public static
        AffineTransform getPreserveAspectRatioTransform(Element e,
                                                        String viewBox,
                                                        String aspectRatio,
                                                        float w,
                                                        float h,
                                                        BridgeContext ctx) {

        // no viewBox specified
        if (viewBox.length() == 0) {
            return new AffineTransform();
        }
        float[] vb = parseViewBoxAttribute(e, viewBox, ctx);

        // 'preserveAspectRatio' attribute
        PreserveAspectRatioParser p = new PreserveAspectRatioParser();
        ViewHandler ph = new ViewHandler();
        p.setPreserveAspectRatioHandler(ph);
        try {
            p.parse(aspectRatio);
        } catch (ParseException pEx ) {
            throw new BridgeException
                (ctx, e, pEx, ERR_ATTRIBUTE_VALUE_MALFORMED,
                 new Object[] {SVG_PRESERVE_ASPECT_RATIO_ATTRIBUTE,
                                   aspectRatio, pEx });
        }

        return getPreserveAspectRatioTransform(vb, ph.align, ph.meet, w, h);
    }

    /**
     * Returns the transformation matrix to apply to initalize a viewport or
     * null if the specified viewBox disables the rendering of the element.
     *
     * @param e the element with a viewbox
     * @param vb the viewBox definition as float
     * @param w the width of the effective viewport
     * @param h The height of the effective viewport
     * @param ctx The BridgeContext to use for error information
     */
    public static
        AffineTransform getPreserveAspectRatioTransform(Element e,
                                                        float[] vb,
                                                        float w,
                                                        float h,
                                                        BridgeContext ctx) {

        String aspectRatio
            = e.getAttributeNS(null, SVG_PRESERVE_ASPECT_RATIO_ATTRIBUTE);

        // 'preserveAspectRatio' attribute
        PreserveAspectRatioParser p = new PreserveAspectRatioParser();
        ViewHandler ph = new ViewHandler();
        p.setPreserveAspectRatioHandler(ph);
        try {
            p.parse(aspectRatio);
        } catch (ParseException pEx ) {
            throw new BridgeException
                (ctx, e, pEx, ERR_ATTRIBUTE_VALUE_MALFORMED,
                 new Object[] {SVG_PRESERVE_ASPECT_RATIO_ATTRIBUTE,
                                   aspectRatio, pEx });
        }

        return getPreserveAspectRatioTransform(vb, ph.align, ph.meet, w, h);
    }

    /**
     * Returns the transformation matrix to apply to initalize a viewport or
     * null if the specified viewBox disables the rendering of the element.
     *
     * @param e the element with a viewbox
     * @param vb the viewBox definition as float
     * @param w the width of the effective viewport
     * @param h The height of the effective viewport
     * @param aPAR The animated preserveAspectRatio value
     * @param ctx The BridgeContext to use for error information
     */
    public static AffineTransform getPreserveAspectRatioTransform
            (Element e, float[] vb, float w, float h,
             SVGAnimatedPreserveAspectRatio aPAR, BridgeContext ctx) {

        // 'preserveAspectRatio' attribute
        try {
            SVGPreserveAspectRatio pAR = aPAR.getAnimVal();
            short align = pAR.getAlign();
            boolean meet = pAR.getMeetOrSlice() ==
                SVGPreserveAspectRatio.SVG_MEETORSLICE_MEET;
            return getPreserveAspectRatioTransform(vb, align, meet, w, h);
        } catch (LiveAttributeException ex) {
            throw new BridgeException(ctx, ex);
        }
    }

    /**
     * Returns the transformation matrix to apply to initialize a viewport or
     * null if the specified viewBox disables the rendering of the element.
     *
     * @param e the element with a viewbox
     * @param aViewBox the viewBox definition
     * @param aPAR the preserveAspectRatio definition
     * @param w the width of the effective viewport
     * @param h the height of the effective viewport
     * @param ctx the BridgeContext to use for error information
     */
    public static AffineTransform getPreserveAspectRatioTransform
            (Element e, SVGAnimatedRect aViewBox,
             SVGAnimatedPreserveAspectRatio aPAR,
             float w, float h, BridgeContext ctx) {

        if (!((SVGOMAnimatedRect) aViewBox).isSpecified()) {
            // no viewBox specified
            return new AffineTransform();
        }
        SVGRect viewBox = aViewBox.getAnimVal();
        float[] vb = new float[] { viewBox.getX(), viewBox.getY(),
                                   viewBox.getWidth(), viewBox.getHeight() };

        return getPreserveAspectRatioTransform(e, vb, w, h, aPAR, ctx);
    }

    /**
     * Parses a viewBox attribute.
     *
     * @param e the element whose viewBox attribute value is being parsed
     * @param value the viewBox
     * @param ctx the BridgeContext to use for error information
     * @return The 4 viewbox components or null.
     */
    public static float[] parseViewBoxAttribute(Element e, String value,
                                                BridgeContext ctx) {
        if (value.length() == 0) {
            return null;
        }
        int i = 0;
        float[] vb = new float[4];
        StringTokenizer st = new StringTokenizer(value, " ,");
        try {
            while (i < 4 && st.hasMoreTokens()) {
                vb[i] = Float.parseFloat(st.nextToken());
                i++;
            }
        } catch (NumberFormatException nfEx ) {
            throw new BridgeException
                (ctx, e, nfEx, ERR_ATTRIBUTE_VALUE_MALFORMED,
                 new Object[] {SVG_VIEW_BOX_ATTRIBUTE, value, nfEx });
        }
        if (i != 4) {
            throw new BridgeException
                (ctx, e, ERR_ATTRIBUTE_VALUE_MALFORMED,
                 new Object[] {SVG_VIEW_BOX_ATTRIBUTE, value});
        }
        // A negative value for <width> or <height> is an error
        if (vb[2] < 0 || vb[3] < 0) {
            throw new BridgeException
                (ctx, e, ERR_ATTRIBUTE_VALUE_MALFORMED,
                 new Object[] {SVG_VIEW_BOX_ATTRIBUTE, value});
        }
        // A value of zero for width or height disables rendering of the element
        if (vb[2] == 0 || vb[3] == 0) {
            return null; // <!> FIXME : must disable !
        }
        return vb;
    }

    /**
     * Returns the preserveAspectRatio transform according to the specified
     * parameters.
     *
     * @param vb the viewBox definition
     * @param align the alignment definition
     * @param meet true means 'meet', false means 'slice'
     * @param w the width of the region in which the document has to fit into
     * @param h the height of the region in which the document has to fit into
     */
    public static
        AffineTransform getPreserveAspectRatioTransform(float [] vb,
                                                        short align,
                                                        boolean meet,
                                                        float w,
                                                        float h) {
        if (vb == null) {
            return new AffineTransform();
        }

        AffineTransform result = new AffineTransform();
        float vpar  = vb[2] / vb[3];
        float svgar = w / h;

        if (align == SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_NONE) {
            result.scale(w / vb[2], h / vb[3]);
            result.translate(-vb[0], -vb[1]);
        } else if (vpar < svgar && meet || vpar >= svgar && !meet) {
            float sf = h / vb[3];
            result.scale(sf, sf);
            switch (align) {
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMINYMIN:
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMINYMID:
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMINYMAX:
                result.translate(-vb[0], -vb[1]);
                break;
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMIDYMIN:
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMIDYMID:
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMIDYMAX:
                result.translate(-vb[0] - (vb[2] - w * vb[3] / h) / 2 , -vb[1]);
                break;
            default:
                result.translate(-vb[0] - (vb[2] - w * vb[3] / h) , -vb[1]);
            }
        } else {
            float sf = w / vb[2];
            result.scale(sf, sf);
            switch (align) {
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMINYMIN:
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMIDYMIN:
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMAXYMIN:
                result.translate(-vb[0], -vb[1]);
                break;
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMINYMID:
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMIDYMID:
            case SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMAXYMID:
                result.translate(-vb[0], -vb[1] - (vb[3] - h * vb[2] / w) / 2);
                break;
            default:
                result.translate(-vb[0], -vb[1] - (vb[3] - h * vb[2] / w));
            }
        }
        return result;
    }

    /**
     * This class can be used to store the value of the attribute viewBox or can
     * also be used to store the various attribute value that can be specified
     * on a SVG URI fragments.
     */
    protected static class ViewHandler extends AWTTransformProducer
        implements FragmentIdentifierHandler {


        /**
         * Constructs a new <code>ViewHandler</code> instance.
         */
        protected ViewHandler() { }

        //////////////////////////////////////////////////////////////////////
        // TransformListHandler
        //////////////////////////////////////////////////////////////////////

        public boolean hasTransform;

        public void endTransformList() throws ParseException {
            super.endTransformList();
            hasTransform = true;
        }

        //////////////////////////////////////////////////////////////////////
        // FragmentIdentifierHandler
        //////////////////////////////////////////////////////////////////////

        public boolean hasId;
        public boolean hasViewBox;
        public boolean hasViewTargetParams;
        public boolean hasZoomAndPanParams;

        public String id;
        public float [] viewBox;
        public String viewTargetParams;
        public boolean isMagnify;

        /**
         * Invoked when the fragment identifier starts.
         * @exception ParseException if an error occured while processing the
         *                           fragment identifier
         */
        public void startFragmentIdentifier() throws ParseException { }

        /**
         * Invoked when an ID has been parsed.
         * @param s The string that represents the parsed ID.
         * @exception ParseException if an error occured while processing the
         *                           fragment identifier
         */
        public void idReference(String s) throws ParseException {
            id = s;
            hasId = true;
        }

        /**
         * Invoked when 'viewBox(x,y,width,height)' has been parsed.
         * @param x the viewbox x coordinate
         * @param y the viewbox y coordinate
         * @param width the viewbox width
         * @param height the viewbox height
         * @exception ParseException if an error occured while processing the
         *                           fragment identifier
         */
        public void viewBox(float x, float y, float width, float height)
            throws ParseException {

            hasViewBox = true;
            viewBox = new float[4];
            viewBox[0] = x;
            viewBox[1] = y;
            viewBox[2] = width;
            viewBox[3] = height;
        }

        /**
         * Invoked when a view target specification starts.
         * @exception ParseException if an error occured while processing the
         *                           fragment identifier
         */
        public void startViewTarget() throws ParseException { }

        /**
         * Invoked when a identifier has been parsed within a view target
         * specification.
         * @param name the target name.
         * @exception ParseException if an error occured while processing the
         *                           fragment identifier
         */
        public void viewTarget(String name) throws ParseException {
            viewTargetParams = name;
            hasViewTargetParams = true;
        }

        /**
         * Invoked when a view target specification ends.
         * @exception ParseException if an error occured while processing the
         *                           fragment identifier
         */
        public void endViewTarget() throws ParseException { }

        /**
         * Invoked when a 'zoomAndPan' specification has been parsed.
         * @param magnify true if 'magnify' has been parsed.
         * @exception ParseException if an error occured while processing the
         *                           fragment identifier
         */
        public void zoomAndPan(boolean magnify) {
            isMagnify = magnify;
            hasZoomAndPanParams = true;
        }

        /**
         * Invoked when the fragment identifier ends.
         * @exception ParseException if an error occured while processing the
         *                           fragment identifier
         */
        public void endFragmentIdentifier() throws ParseException { }

        //////////////////////////////////////////////////////////////////////
        // PreserveAspectRatioHandler
        //////////////////////////////////////////////////////////////////////

        public boolean hasPreserveAspectRatio;

        public short align;
        public boolean meet = true;

        /**
         * Invoked when the PreserveAspectRatio parsing starts.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void startPreserveAspectRatio() throws ParseException { }

        /**
         * Invoked when 'none' been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void none() throws ParseException {
            align = SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_NONE;
        }

        /**
         * Invoked when 'xMaxYMax' has been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void xMaxYMax() throws ParseException {
            align = SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMAXYMAX;
        }

        /**
         * Invoked when 'xMaxYMid' has been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void xMaxYMid() throws ParseException {
            align = SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMAXYMID;
        }

        /**
         * Invoked when 'xMaxYMin' has been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void xMaxYMin() throws ParseException {
            align = SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMAXYMIN;
        }

        /**
         * Invoked when 'xMidYMax' has been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void xMidYMax() throws ParseException {
            align = SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMIDYMAX;
        }

        /**
         * Invoked when 'xMidYMid' has been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void xMidYMid() throws ParseException {
            align = SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMIDYMID;
        }

        /**
         * Invoked when 'xMidYMin' has been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void xMidYMin() throws ParseException {
            align = SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMIDYMIN;
        }

        /**
         * Invoked when 'xMinYMax' has been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void xMinYMax() throws ParseException {
            align = SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMINYMAX;
        }

        /**
         * Invoked when 'xMinYMid' has been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void xMinYMid() throws ParseException {
            align = SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMINYMID;
        }

        /**
         * Invoked when 'xMinYMin' has been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void xMinYMin() throws ParseException {
            align = SVGPreserveAspectRatio.SVG_PRESERVEASPECTRATIO_XMINYMIN;
        }

        /**
         * Invoked when 'meet' has been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void meet() throws ParseException {
            meet = true;
        }

        /**
         * Invoked when 'slice' has been parsed.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void slice() throws ParseException {
            meet = false;
        }

        /**
         * Invoked when the PreserveAspectRatio parsing ends.
         * @exception ParseException if an error occured while processing
         * the transform
         */
        public void endPreserveAspectRatio() throws ParseException {
            hasPreserveAspectRatio = true;
        }
    }
}