PDFlib Cookbook

cookbook

images/tiling_pattern

Define a tiling pattern containing an image and use it to cover the page background with tiles.

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/*
 * Tiling pattern:
 * Define a tiling pattern containing an image and use it to cover the page
 * background with tiles.
 * 
 * Required software: PDFlib/PDFlib+PDI/PPS 9.0.2
 * Required data: image file
 */
package com.pdflib.cookbook.pdflib.images;

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

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

        pdflib p = null;
        int exitcode = 0;
        String imagefile = "background_image.png";
        int font, image, pattern;
        int pagewidth = 595, pageheight = 842;
        double imagewidth, imageheight, resx, resy;

        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);

            /* Load the background image */
            image = p.load_image("auto", imagefile, "");
            if (image == -1)
                throw new Exception("Error: " + p.get_errmsg());

            /* Retrieve the image dimensions */
            imagewidth = p.info_image(image, "imagewidth", "");
            imageheight = p.info_image(image, "imageheight", "");

            /*
             * The image may have a resolution above 72 dpi. If we used the
             * returned dimensions (in points) for the pattern height and width
             * and placed our image into the pattern, it wouldn't match the
             * pattern size, and a white margin would be left. To make the
             * pattern the same size as the image we calculate the image size
             * based on its resolution.
             * 
             * Retrieve the original image resolution:
             */
            resx = p.info_image(image, "resx", "");
            resy = p.info_image(image, "resy", "");

            /* Calculate the image dimensions for 72 dpi */
            if (resx > 0) {
                imagewidth = imagewidth * 72 / resx;
                imageheight = imageheight * 72 / resy;
            }

            /*
             * Create a pattern using the retrieved image dimensions. The
             * painttype parameter must be set to 1 since a colorized image is
             * used (as opposed to an image mask).
             */
            pattern = p.begin_pattern_ext(imagewidth, imageheight, "");
            p.fit_image(image, 0, 0, "");
            p.end_pattern();
            p.close_image(image);

            /* Start page */
            p.begin_page_ext(pagewidth, pageheight, "");

            /*
             * Set a fill color and create and fill a rectangle with the
             * dimensions of the page. Encapsulate the setcolor() call with
             * save() and restore() to be able to proceed with the original
             * colors.
             */
            p.save();
            p.setcolor("fill", "pattern", pattern, 0, 0, 0);
            p.rect(0, 0, pagewidth, pageheight);
            p.fill();
            p.restore();

            /* Output some page contents */
            font = p.load_font("NotoSerif-Bold", "unicode", "");
            if (font == -1)
                throw new Exception("Error: " + p.get_errmsg());

            int fontsize = 14;
            p.set_text_option("font=" + font + " fontsize=" + fontsize);
            p.fit_textline(
                "The page background consists of a small image pattern",
                20, 700, "");
            p.fit_textline(
                "which will be output on the page repeatedly.",
                20, 700 - fontsize, "");

            p.end_page_ext("");

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