/*
 * Copyright 1999-2005 The Apache Software Foundation.
 * 
 * Licensed 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.render.ps;

import java.io.IOException;
import java.io.Serializable;
import java.util.List;
import java.awt.Color;
import java.awt.geom.AffineTransform;

/**
 * This class holds the current state of the PostScript interpreter.
 * 
 * @author <a href="mailto:fop-dev@xml.apache.org">Apache XML FOP Development Team</a>
 * @version $Id$
 */
public class PSState implements Serializable {

    /** Default for setdash */
    public static final String DEFAULT_DASH = "[] 0"; 
    /** Default color in PostScript */
    public static final Color DEFAULT_RGB_COLOR = Color.black; 
    
    private AffineTransform transform = new AffineTransform();
    private List transformConcatList = new java.util.ArrayList();
 
    private int linecap = 0;
    private double linewidth = 1.0f;
    private String dashpattern = DEFAULT_DASH;
    private Color rgbColor = DEFAULT_RGB_COLOR;
    
    //Font state
    private String fontname;
    private float fontsize;

    /**
     * Default constructor
     */
    public PSState() {
        //nop
    }

    /**
     * Copy constructor
     * @param org the original to copy from
     * @param copyTransforms true if the list of matrix concats should be cloned, too
     */
    public PSState(PSState org, boolean copyTransforms) {
        this.transform = (AffineTransform)org.transform.clone();
        if (copyTransforms) {
            this.transformConcatList.addAll(org.transformConcatList);
        }
        this.linecap = org.linecap;
        this.linewidth = org.linewidth;
        this.dashpattern = org.dashpattern;
        this.rgbColor = org.rgbColor;
        this.fontname = org.fontname;
        this.fontsize = org.fontsize;
    }
 
    /**
     * Returns the transform.
     * @return the current transformation matrix
     */
    public AffineTransform getTransform() {
        return this.transform;
    }

    /**
     * Check the current transform.
     * The transform for the current state is the combination of all
     * transforms in the current state. The parameter is compared
     * against this current transform.
     *
     * @param tf the transform the check against
     * @return true if the new transform is different then the current transform
     */
    public boolean checkTransform(AffineTransform tf) {
        return !tf.equals(this.transform);
    }
    
    /**
     * Concats the given transformation matrix with the current one.
     * @param transform The new transformation matrix
     */
    public void concatMatrix(AffineTransform transform) {
        this.transformConcatList.add(transform);
        this.transform.concatenate(transform);
    }

    /**
     * Establishes the specified line cap.
     * @param value line cap (0, 1 or 2) as defined by the setlinecap command
     * @return true if the line cap changed compared to the previous setting
     */
    public boolean useLineCap(int value) {
        if (linecap != value) {
            linecap = value;
            return true;
        } else {
            return false;
        }
    }
    
    /**
     * Establishes the specified line width.
     * @param value line width as defined by the setlinewidth command
     * @return true if the line width changed compared to the previous setting
     */
    public boolean useLineWidth(double value) {
        if (linewidth != value) {
            linewidth = value;
            return true;
        } else {
            return false;
        }
    }
    
    /**
     * Establishes the specified dash.
     * @param pattern dash pattern as defined by the setdash command
     * @return true if the dash pattern changed compared to the previous setting
     */
    public boolean useDash(String pattern) {
        if (!dashpattern.equals(pattern)) {
            dashpattern = pattern;
            return true;
        } else {
            return false;
        }
    }
    
    /**
     * Establishes the specified color (RGB).
     * @param value color as defined by the setrgbcolor command
     * @return true if the color changed compared to the previous setting
     */
    public boolean useColor(Color value) {
        if (!rgbColor.equals(value)) {
            rgbColor = value;
            return true;
        } else {
            return false;
        }
    }
    
    /**
     * Establishes the specified font and size.
     * @param name name of the font for the "F" command (see FOP Std Proc Set)
     * @param size size of the font
     * @return true if the font changed compared to the previous setting
     */
    public boolean useFont(String name, float size) {
        if (name == null) {
            throw new NullPointerException("font name must not be null");
        }
        if (fontname == null || !fontname.equals(name) || fontsize != size) {
            fontname = name;
            fontsize = size;
            return true;
        } else {
            return false;
        }
    }
    
    /**
     * Reestablishes the graphics state represented by this instance by issueing the
     * necessary commands.
     * @param gen The generator to use for output
     * @exception IOException In case of an I/O problem
     */
    public void reestablish(PSGenerator gen) throws IOException {
        for (int i = 0, len = transformConcatList.size(); i < len; i++) {
            gen.concatMatrix((AffineTransform)transformConcatList.get(i));
        }
        gen.useLineCap(linecap);
        gen.useLineWidth(linewidth);
        gen.useDash(dashpattern);
        gen.useRGBColor(rgbColor);
        if (fontname != null) {
            gen.useFont(fontname, fontsize);
        }
    }
    
}