fop/src/java/org/apache/fop/fo/properties/FixedLength.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.
 */

/* $Id$ */

package org.apache.fop.fo.properties;

import org.apache.fop.datatypes.PercentBaseContext;

/**
 * An absolute length quantity in XSL
 */
public class FixedLength extends LengthProperty {
    
    /** cache holding all canonical FixedLength instances */
    private static final PropertyCache cache = new PropertyCache();
    
    private int millipoints;

    /**
     * Set the length given a number of units and a unit name.
     * @param numUnits quantity of input units
     * @param units input unit specifier (in, cm, etc.)
     */
    private FixedLength(double numUnits, String units) {
        convert(numUnits, units);
    }
    
    /**
     * Return the canonical FixedLength instance corresponding
     * to the computed value
     * @param numUnits  input units
     * @param units     unit specifier
     * @return  the canonical FixedLength instance corresponding
     *          to the given number of units and unit specifier
     */
    public static FixedLength getInstance(double numUnits, String units) {
        return (FixedLength) cache.fetch(
                    new FixedLength(numUnits, units));
        
    }
    
    /**
     * @param baseUnits the length as a number of base units (millipoints)
     */
    public FixedLength(int baseUnits) {
        millipoints = baseUnits;
    }

    /**
     * Convert the given length to a dimensionless integer representing
     * a whole number of base units (milli-points).
     * @param dvalue quantity of input units
     * @param unit input unit specifier (in, cm, etc.)
     */
    protected void convert(double dvalue, String unit) {
        // TODO: the whole routine smells fishy.

        int assumedResolution = 1;    // points/pixel = 72dpi

        if (unit.equals("in")) {
            dvalue = dvalue * 72;
        } else if (unit.equals("cm")) {
            dvalue = dvalue * 28.3464567;
        } else if (unit.equals("mm")) {
            dvalue = dvalue * 2.83464567;
        } else if (unit.equals("pt")) {
            // Do nothing.
            // dvalue = dvalue;
        } else if (unit.equals("mpt")) { //mpt is non-standard!!! mpt=millipoints
            // TODO: this seems to be wrong.
            // Do nothing.
            // dvalue = dvalue;
        } else if (unit.equals("pc")) {
            dvalue = dvalue * 12;
            /*
             * } else if (unit.equals("em")) {
             * dvalue = dvalue * fontsize;
             */
        } else if (unit.equals("px")) {
            // TODO: get resolution from user agent?
            dvalue = dvalue * assumedResolution;
        } else {
            dvalue = 0;
            log.error("Unknown length unit '" + unit + "'");
        }
        if (unit.equals("mpt")) {
            millipoints = (int)dvalue;
        } else {
            millipoints = (int)(dvalue * 1000);
        }
    }

    /**
     * {@inheritDoc}
     */
    public int getValue() {
        return millipoints;
    }

    /**
     * {@inheritDoc}
     */
    public int getValue(PercentBaseContext context) {
        return millipoints;
    }

    /**
     * {@inheritDoc}
     */
    public double getNumericValue() {
        return millipoints;
    }

    /**
     * {@inheritDoc}
     */
    public double getNumericValue(PercentBaseContext context) {
        return millipoints;
    }

    /**
     * Return true since FixedLength are always absolute.
     * {@inheritDoc}
     */
    public boolean isAbsolute() {
        return true;
    }

    /**
     * {@inheritDoc}
     */
    public String toString() {
        return millipoints + "mpt";
    }

    /**
     * {@inheritDoc}
     */
    public boolean equals(Object obj) {
        if (obj instanceof FixedLength) {
            return (((FixedLength)obj).millipoints == this.millipoints);
        } else {
            return false;
        }
    }

    /**
     * {@inheritDoc}
     */
    public int hashCode() {
        return millipoints;
    }
}