PDFlib Cookbook

cookbook

blocks/query_block_color

Query the background color of Blocks.

Download Java Code  Switch to PHP Code  Show Output  Show Input (blocks_bgcolor.pdf) 

/*
 * Query block color:
 * Query the background color of blocks
 * 
 * Import a page containing blocks and query the background color space and 
 * color of all blocks.
 *
 * Required software: PPS 9
 * Required data: PDF document with blocks
 */
package com.pdflib.cookbook.pdflib.blocks;

import java.text.NumberFormat;
import java.util.*;

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

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

        pdflib p = null;
        String infile = "blocks_bgcolor.pdf";
        int exitcode = 0;
        
        String colorspace, path, blockname, type, textbuf;
        int i, j, font, page, indoc, blockcount;
        int x = 30, y = 750, yoff = 30, ncomp = 1;
        double comp;
        NumberFormat form = NumberFormat.getInstance(Locale.US);
        
        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 font */
            font = p.load_font("Helvetica", "unicode", "");

            if (font == -1)
                throw new Exception("Error: " + p.get_errmsg());
            
            /* Open a PDF containing blocks */
            indoc = p.open_pdi_document(infile, "");
            if (indoc == -1)
                throw new Exception("Error: " + p.get_errmsg());

            /* Open the first input page */
            page = p.open_pdi_page(indoc, 1, "");
            if (page == -1)
                throw new Exception("Error: " + p.get_errmsg());

            /* Start the first output page */
            p.begin_page_ext(0, 0, "width=a4.width height=a4.height");
            
            /* Set the font with a font size of 14 */
            p.setfont(font, 14);
            
            /* Set the number of fraction digits to 2 */
            form.setMaximumFractionDigits(2);
            form.setMinimumFractionDigits(2);
                  
            /* Get the number of blocks on the page */
            blockcount = (int) p.pcos_get_number(indoc, "length:pages[0]/blocks");

            if (blockcount == 0)
                throw new Exception("Error: " + infile +
                    "does not contain any PDFlib blocks");

            
            /* -------------------------------------------------------------------
             * Query the background color space and color of all blocks. The color
             * space can be DeviceGray, DeviceRGB, DeviceCMYK, Separation, or Lab.
             * -------------------------------------------------------------------
             */
            
            for (i = 0; i < blockcount; i++) 
            {
                /* Retrieve the block name */
                blockname = p.pcos_get_string(indoc,
                    "pages[0]/blocks[" + i + "]/Name");
                
                /* Output the block name */
                textbuf = "Background color of \"" + blockname + "\" is:";
                p.fit_textline(textbuf,x, y-=yoff, "");
          
                /* Set the pCOS path for the background color */
                path = "pages[0]/blocks[" + i + "]/backgroundcolor";
                
                type = p.pcos_get_string(indoc, "type:" + path);
                           
                /* Check, if a background color is available */
                if (type.equals("null")) {
                    textbuf = "not available";   
                }
                else if (type.equals("array")) {
                    /* Get the path type */
                    type = p.pcos_get_string(indoc, "type:" + path + "[0]");
                    
                    /* Check for DeviceGray, DeviceRGB, or DeviceCMYK color space */
                    if (type.equals("name")) {
                        colorspace = p.pcos_get_string(indoc, path + "[0]");
                                    
                        textbuf = colorspace + " ";
                
                        if (colorspace.equals("DeviceGray"))
                            ncomp = 1;
                        else if (colorspace.equals("DeviceRGB"))
                            ncomp = 3;
                        else if (colorspace.equals("DeviceCMYK"))
                            ncomp = 4;
                        else
                            throw new Exception("Unknown color space");
                    }
                    else if (type.equals("array")){
                        /* Check for Separation or Lab color space; in these cases 
                         * the color space itself is an array
                         */ 
                        colorspace = p.pcos_get_string(indoc, path + "[0][0]"); 
                
                        textbuf = colorspace + " ";
                    
                        if (colorspace.equals("Separation")) {
                            String name = p.pcos_get_string(indoc, path + "[0][1]");
                            textbuf = textbuf + "\"" + name + "\"" + " ";
                            ncomp = 1;
                        }
                        else if (colorspace.equals("Lab"))
                            ncomp = 3;
                        else 
                            throw new Exception("Unknown color space");
                    }
                    else {
                        throw new Exception("Unknown color space");
                    }
                                
                    /* Get one or more color components */
                    if (ncomp == 1) {
                        comp = p.pcos_get_number(indoc, path + "[1]");
                        textbuf = textbuf + form.format(comp);
                    }
                    else
                    {
                        textbuf = textbuf + " [";
                        for (j = 0; j < ncomp; ++j) {
                            comp = 
                                p.pcos_get_number(indoc, path + "[1][" + j + "]");
                            textbuf = textbuf + " " + form.format(comp) + " ";
                        }
                        textbuf = textbuf + "]";
                    }
                }
                else {
                    throw new Exception("Unknown color space");
                }
                            
                /* Output the color space and color of the block */
                p.fit_textline(textbuf, x, y-=yoff, "fillcolor={rgb 0.2 0.4 0.7}");
                
            } /* for */
            p.end_page_ext("");
                  
            p.close_pdi_page(page);

            p.end_document("");
            p.close_pdi_document(indoc);

        } 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.toString());
            exitcode = 1;
        } finally {
            if (p != null) {
                p.delete();
            }
            System.exit(exitcode);
        }
    }
}