AbstractTextRenderer.java

/*
 * Copyright (c) 2009 Piotr Piastucki
 * 
 * This file is part of Patchca CAPTCHA library.
 * 
 *  Patchca is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU Lesser General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 *  
 *  Patchca is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU Lesser General Public License for more details.
 *  
 *  You should have received a copy of the GNU Lesser General Public License
 *  along with Patchca. If not, see <http://www.gnu.org/licenses/>.
 */
package com.xiongyingqi.captcha.text.renderer;

import com.xiongyingqi.captcha.color.ColorFactory;
import com.xiongyingqi.captcha.font.FontFactory;

import java.awt.*;
import java.awt.font.FontRenderContext;
import java.awt.geom.Rectangle2D;
import java.awt.image.BufferedImage;

public abstract class AbstractTextRenderer implements TextRenderer {

    protected int leftMargin;
    protected int rightMargin;
    protected int topMargin;
    protected int bottomMargin;

    protected abstract void arrangeCharacters(int width, int height, TextString ts);

    public AbstractTextRenderer() {
        leftMargin = rightMargin = 5;
        topMargin = bottomMargin = 5;
    }

    @Override
    public void setLeftMargin(int leftMargin) {
        this.leftMargin = leftMargin;
    }

    @Override
    public void setRightMargin(int rightMargin) {
        this.rightMargin = rightMargin;
    }

    @Override
    public void setTopMargin(int topMargin) {
        this.topMargin = topMargin;
    }

    @Override
    public void setBottomMargin(int bottomMargin) {
        this.bottomMargin = bottomMargin;
    }

    @Override
    public void draw(String text, BufferedImage canvas, FontFactory fontFactory, ColorFactory colorFactory) {
        Graphics2D g = (Graphics2D) canvas.getGraphics();
        TextString ts = convertToCharacters(text, g, fontFactory, colorFactory);
        arrangeCharacters(canvas.getWidth(), canvas.getHeight(), ts);
        g.setRenderingHint(RenderingHints.KEY_ANTIALIASING, RenderingHints.VALUE_ANTIALIAS_ON);
        g.setRenderingHint(RenderingHints.KEY_FRACTIONALMETRICS, RenderingHints.VALUE_FRACTIONALMETRICS_ON);
        g.setRenderingHint(RenderingHints.KEY_RENDERING, RenderingHints.VALUE_RENDER_QUALITY);
        for (TextCharacter tc : ts.getCharacters()) {
            g.setColor(tc.getColor());
            g.drawString(tc.iterator(), (float) tc.getX(), (float) tc.getY());
        }
    }

    protected TextString convertToCharacters(String text, Graphics2D g, FontFactory fontFactory, ColorFactory colorFactory) {
        TextString characters = new TextString();
        FontRenderContext frc = g.getFontRenderContext();
        double lastx = 0;
        for (int i = 0; i < text.length(); i++) {
            Font font = fontFactory.getFont(i);
            char c = text.charAt(i);
            FontMetrics fm = g.getFontMetrics(font);
            Rectangle2D bounds = font.getStringBounds(String.valueOf(c), frc);
            TextCharacter tc = new TextCharacter();
            tc.setCharacter(c);
            tc.setFont(font);
            tc.setWidth(fm.charWidth(c));
            tc.setHeight(fm.getAscent() + fm.getDescent());
            tc.setAscent(fm.getAscent());
            tc.setDescent(fm.getDescent());
            tc.setX(lastx);
            tc.setY(0);
            tc.setFont(font);
            tc.setColor(colorFactory.getColor(i));
            lastx += bounds.getWidth();
            characters.addCharacter(tc);
        }
        return characters;
    }

}