PDFlib Cookbook

cookbook

images/image_mask

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/* $Id: image_mask.java,v 1.10 2017/01/24 14:06:54 stm Exp $
 * Image mask:
 * Place an image with a mask applied to it
 * 
 * Place an image and apply a Grayscale mask on it. Depending on the values
 * contained in the mask, the image pixels will be displayed more or less 
 * transparent. Smaller (darker) mask values result in more transparent image 
 * pixels and larger (lighter) values in less transparency.
 *
 * Required software: PDFlib/PDFlib+PDI/PPS 9
 * Required data: image file
 */
package com.pdflib.cookbook.pdflib.images;

import com.pdflib.pdflib;
import com.pdflib.PDFlibException;

public class image_mask
{
    public static void main (String argv[])
    {
	/* This is where the data files are. Adjust as necessary. */
	String searchpath = "../input";
	String outfile = "image_mask.pdf";
	String title = "Image Mask";

	pdflib p = null;
	int exitcode = 0;
	String imagefile = "sky.jpg";
	String maskfile = "image_mask.jpg";
	int font, image, mask, masked_image;
      
	try {
	    p = new pdflib();

	    p.set_option("searchpath={" + searchpath + "}");

	    /* This means we must check return values of load_font() etc. */
	    p.set_option("errorpolicy=return");

	    if (p.begin_document(outfile, "") == -1)
		throw new Exception("Error: " + p.get_errmsg());

	    p.set_info("Creator", "PDFlib Cookbook");
	    p.set_info("Title", title + " $Revision: 1.10 $");
	    
	    /* Load the original image */
	    image = p.load_image("auto", imagefile, "");
	    if (image == -1)
		throw new Exception("Error: " + p.get_errmsg());

	    /*
	     * Load the Grayscale image to be used as the transparency mask.
	     * It must not have an ICC profile, as an image with an ICCBased
	     * colorspace cannot be used as a mask.
	     */
	    mask = p.load_image("auto", maskfile, "honoriccprofile=false");
	    if (mask == -1)
		throw new Exception("Error: " + p.get_errmsg());
	    
	    /* Load the image with the transparency mask being assigned to it */
	    masked_image = p.load_image("auto", imagefile, "masked " + mask);
	    if (masked_image == -1)
		throw new Exception("Error: " + p.get_errmsg());
	    
	    /* Load font */
	    font = p.load_font("Helvetica", "unicode", "");
	    if (font == -1)
		throw new Exception("Error: " + p.get_errmsg());

	    /* Start a page with a size similar to the image dimensions. 
	     * The "transparencygroup" option improves output quality when placing
	     * the image on a page which contains transparent objects (image or
	     * other).
	     * PDFlib 7.0.3 will automatically create the "transparencygroup"
	     * option, so it is only required in earlier versions.
	     */
	    p.begin_page_ext(0, 0, "width=a4.height height=a4.width " +
		"transparencygroup={CS=DeviceRGB}");
	    
	    /* Place the original image */
	    p.fit_image(image, 50, 150, "boxsize {200 500} fitmethod=meet");
	    p.fit_textline("Original image", 50, 130, "font=" + font +
		" fontsize=14");
	    
	    /* Place the image without the clipping path being applied to it */
	    p.fit_image(mask, 300, 150, "boxsize {200 500} fitmethod=meet");
	    p.fit_textline("Transparency mask", 300, 130, "font=" + font +
		" fontsize=14");
	    
	    /* Place the image with the clipping path being applied to it */
	    p.fit_image(masked_image, 550, 150, "boxsize {200 500} fitmethod=meet");
	    p.fit_textline("Image with the transparency mask applied.", 550, 130,
		"font=" + font + " fontsize=10");
	    p.fit_textline("Darker mask values result in more transparent image " +
		"values.", 550, 110, "font=" + font + " fontsize=10");
		    
	    /* Close the images */
	    p.close_image(image);
	    p.close_image(mask);
	    p.close_image(masked_image);
	 
	    p.end_page_ext("");
	    p.end_document("");

        } catch (PDFlibException e) {
            System.err.print("PDFlib exception occurred:\n");
            System.err.print("[" + e.get_errnum() + "] " + e.get_apiname() +
                ": " + e.get_errmsg() + "\n");
	    exitcode = 1;
        } catch (Exception e) {
            System.err.println(e.getMessage());
	    exitcode = 1;
        } finally {
            if (p != null) {
                p.delete();
            }
	    System.exit(exitcode);
        }
    }
}