src/java/org/apache/fop/fo/expr/CIELabColorFunction.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.expr;
import org.apache.fop.apps.FOUserAgent;
import org.apache.fop.datatypes.PercentBase;
import org.apache.fop.datatypes.PercentBaseContext;
import org.apache.fop.fo.properties.ColorProperty;
import org.apache.fop.fo.properties.Property;

/**
 * Implements the cie-lab-color() function.
 * @since XSL-FO 2.0
 */
class CIELabColorFunction extends FunctionBase {

    /**
     * cie-lab-color() takes 2 times 3 arguments.
     * {@inheritDoc}
     */
    public int nbArgs() {
        return 2 * 3;
    }

    public PercentBase getPercentBase() {
        return new CIELabPercentBase();
    }

    /** {@inheritDoc} */
    public Property eval(Property[] args,
                         PropertyInfo pInfo) throws PropertyException {

        float red = args[0].getNumber().floatValue();
        float green = args[1].getNumber().floatValue();
        float blue = args[2].getNumber().floatValue();
        /* Verify sRGB replacement arguments */
        if ((red < 0 || red > 255)
                || (green < 0 || green > 255)
                || (blue < 0 || blue > 255)) {
            throw new PropertyException("sRGB color values out of range. "
                    + "Arguments to cie-lab-color() must be [0..255] or [0%..100%]");
        }

        float l = args[3].getNumber().floatValue();
        float a = args[4].getNumber().floatValue();
        float b = args[5].getNumber().floatValue();
        if (l < 0 || l > 100) {
            throw new PropertyException("L* value out of range. Valid range: [0..100]");
        }
        if (a < -127 || a > 127 || b < -127 || b > 127) {
            throw new PropertyException("a* and b* values out of range. Valid range: [-127..+127]");
        }

        StringBuffer sb = new StringBuffer();
        sb.append("cie-lab-color(" + red + "," + green + "," + blue + ","
                + l + "," + a + "," + b + ")");
        FOUserAgent ua = (pInfo == null)
                ? null
                : (pInfo.getFO() == null ? null : pInfo.getFO().getUserAgent());
        return ColorProperty.getInstance(ua, sb.toString());
    }

    private static class CIELabPercentBase implements PercentBase {
        public int getDimension() {
            return 0;
        }

        public double getBaseValue() {
            return 1.0f;
        }

        public int getBaseLength(PercentBaseContext context) {
            return 0;
        }

    }

}