Transparency.java

/*
 * $Id$
 *
 * This code is part of the 'iText Tutorial'.
 * You can find the complete tutorial at the following address:
 * http://itextdocs.lowagie.com/tutorial/
 *
 * This code 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.
 *
 * itext-questions@lists.sourceforge.net
 */
package com.lowagie.examples.directcontent.colors;

import java.awt.Color;
import java.io.FileOutputStream;

import com.lowagie.text.Document;
import com.lowagie.text.Element;
import com.lowagie.text.PageSize;
import com.lowagie.text.Phrase;
import com.lowagie.text.pdf.ColumnText;
import com.lowagie.text.pdf.PdfContentByte;
import com.lowagie.text.pdf.PdfGState;
import com.lowagie.text.pdf.PdfTemplate;
import com.lowagie.text.pdf.PdfTransparencyGroup;
import com.lowagie.text.pdf.PdfWriter;

/**
 * Demonstrates transparency and images.
 */
public class Transparency {
    
    /**
     * Prints a square and fills half of it with a gray rectangle.
     * @param x
     * @param y
     * @param cb
     * @throws Exception
     */
    public static void pictureBackdrop(float x, float y, PdfContentByte cb) throws Exception {
        cb.setColorStroke(Color.black);
        cb.setColorFill(Color.gray);
        cb.rectangle(x, y, 100, 200);
        cb.fill();
        cb.setLineWidth(2);
        cb.rectangle(x, y, 200, 200);
        cb.stroke();
    }

    /**
     * Prints 3 circles in different colors that intersect with eachother.
     * @param x
     * @param y
     * @param cb
     * @throws Exception
     */
    public static void pictureCircles(float x, float y, PdfContentByte cb) throws Exception {
        cb.setColorFill(Color.red);
        cb.circle(x + 70, y + 70, 50);
        cb.fill();
        cb.setColorFill(Color.yellow);
        cb.circle(x + 100, y + 130, 50);
        cb.fill();
        cb.setColorFill(Color.blue);
        cb.circle(x + 130, y + 70, 50);
        cb.fill();
    }

    /**
     * Demonstrates the Transparency functionality.
     * @param args no arguments needed
     */
    public static void main(String[] args) {
		System.out.println("Transparency");
        // step 1: creation of a document-object
        Document document = new Document(PageSize.A4, 50, 50, 50, 50);
        try {
            // step 2: creation of a writer 
            PdfWriter writer = PdfWriter.getInstance(document, new FileOutputStream("transparency.pdf"));
            // step 3: we open the document
            document.open();
            // step 4: content
            PdfContentByte cb = writer.getDirectContent();
            float gap = (document.getPageSize().getWidth() - 400) / 3;
            
            pictureBackdrop(gap, 500, cb);
            pictureBackdrop(200 + 2 * gap, 500, cb);
            pictureBackdrop(gap, 500 - 200 - gap, cb);
            pictureBackdrop(200 + 2 * gap, 500 - 200 - gap, cb);
            
            pictureCircles(gap, 500, cb);
            cb.saveState();
            PdfGState gs1 = new PdfGState();
            gs1.setFillOpacity(0.5f);
            cb.setGState(gs1);
            pictureCircles(200 + 2 * gap, 500, cb);
            cb.restoreState();

            PdfTemplate tp = cb.createTemplate(200, 200);
            cb.saveState();
            pictureCircles(0, 0, tp);
            PdfTransparencyGroup group = new PdfTransparencyGroup();
            tp.setGroup(group);
            tp.sanityCheck();
            cb.setGState(gs1);
            cb.addTemplate(tp, gap, 500 - 200 - gap);
            cb.restoreState();

            tp = cb.createTemplate(200, 200);
            cb.saveState();
            PdfGState gs2 = new PdfGState();
            gs2.setFillOpacity(0.5f);
            gs2.setBlendMode(PdfGState.BM_SOFTLIGHT);
            tp.setGState(gs2);
            tp.sanityCheck();
            pictureCircles(0, 0, tp);
            tp.setGroup(group);
            cb.addTemplate(tp, 200 + 2 * gap, 500 - 200 - gap);
            cb.restoreState();

            cb.resetRGBColorFill();
            ColumnText ct = new ColumnText(cb);
            Phrase ph = new Phrase("Ungrouped objects\nObject opacity = 1.0");
            ct.setSimpleColumn(ph, gap, 0, gap + 200, 500, 18, Element.ALIGN_CENTER);
            ct.go();
            
            ph = new Phrase("Ungrouped objects\nObject opacity = 0.5");
            ct.setSimpleColumn(ph, 200 + 2 * gap, 0, 200 + 2 * gap + 200, 500, 18, Element.ALIGN_CENTER);
            ct.go();
            
            ph = new Phrase("Transparency group\nObject opacity = 1.0\nGroup opacity = 0.5\nBlend mode = Normal");
            ct.setSimpleColumn(ph, gap, 0, gap + 200, 500 - 200 - gap, 18, Element.ALIGN_CENTER);
            ct.go();
            
            ph = new Phrase("Transparency group\nObject opacity = 0.5\nGroup opacity = 1.0\nBlend mode = SoftLight");
            ct.setSimpleColumn(ph, 200 + 2 * gap, 0, 200 + 2 * gap + 200, 500 - 200 - gap, 18, Element.ALIGN_CENTER);
            ct.go();
            
            cb.sanityCheck();
        }
        catch (Exception de) {
            de.printStackTrace();
        }
        // step 5: we close the document
        document.close();
    }
}