general/function_scopes

 * Function scopes:

 * Explain the concept of scopes of the PDFlib API

 *

 * Create a few pages and output some text, graphics and images. Show how scopes

 * are related and how function calls start or terminate scopes. Show which

 * calls can be used in the respective situation and which calls are not

 * allowed. Use get_parameter("scope", 0) to query the current scope.

 *

 * Required software: PDFlib Lite/PDFlib/PDFlib+PDI/PPS 7

 * Required data: image file

 */

package com.pdflib.cookbook.pdflib.general;

import com.pdflib.pdflib;

import com.pdflib.PDFlibException;

public class function_scopes

{

    public static void main (String argv[])

    {

    /* This is where the data files are. Adjust as necessary. */

    String searchpath = "../input";

    String outfile = "function_scopes.pdf";

    String title = "Function Scopes";

    pdflib p = null;

    String imagefile = "nesrin.jpg";

    String scope;

    int font, image;

    try {

        /* -------------------------------------------------------------------

         * Create a PDFlib object.

         *

         * This call starts scope "object".

         * Only begin_document(), get_buffer(), and encoding_set_char() can be

         * called in this scope.

         * -------------------------------------------------------------------

         */

        p = new pdflib();

        p.set_parameter("SearchPath", searchpath);

        /* This means we must check return values of load_font() etc. */

        p.set_parameter("errorpolicy", "return");

        /* --------------------------------------------------------------------

         * Start the document.

         *

         * This call starts scope "document".

         * The following functions plus some others are allowed in this scope:

         * begin_page_ext(), resume_page(), load_image(), begin_template_ext(),

         * open_pdi_document(), open_pdi_page().

         * --------------------------------------------------------------------

         */

        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: 1.3 $");

        /* We load the image before the first page, and use it on all pages.

         * Loading an image is allowed in scope "document".

         */

        image = p.load_image("auto", imagefile, "");

        if (image == -1)

            throw new Exception("Error: " + p.get_errmsg());

        /* -------------------------------------------------------------------

         * Start the first page.

         *

         * This call starts scope "page".

         * Many functions for creating page content are allowed in this scope.

         * -------------------------------------------------------------------

         */

        p.begin_page_ext(595, 842, "");

        /* Load the font.

         * 

         * Loading a font is allowed in any scope except "object". Therefore,

         * it can also be done in scope "document" before starting the page.

         *

         * For PDFlib Lite: change "unicode" to "winansi".

         */

        font = p.load_font("Helvetica", "unicode", "");

        if (font == -1)

            throw new Exception("Error: " + p.get_errmsg());

        /* Set the font, output an image, and output a text line.

         *

         * These three function calls are allowed in scope "page" but cannot be

         * used in scope "document". This means that the page must have been

         * started first as accomplished above.

         */

        p.setfont(font, 14);

        p.fit_image(image,  200.0,  200.0, "scale=0.25");

        /* Output the scope.

         *

         * Use get_parameter() with the key "scope" to query the current scope.

         */

        scope = p.get_parameter("scope", 0);

        p.fit_textline("The current scope can be retrieved with " +

            "get_parameter(\"scope\", 0);", 20, 700, "");

        /* --------------------------------------------------------------------

         * Complete the first page.

         *

         * This call terminates scope "page". After this call the current scope

         * will be "document" again.

         * --------------------------------------------------------------------

         */

        p.end_page_ext("");

        /* -----------------------------

         * Start the second page.

         *

         * This call starts scope "page"

         * -----------------------------

         */

        p.begin_page_ext(595, 842, "");

        /* Set the current fill color.

         *

         * This call is allowed in scope "page" but cannot be used in scope

         * "document".

         */

        p.setcolor("fill", "rgb", 1.0, 0.0, 0.0, 0.0);

        /* -------------------------------------------------------------------

         * Add a rectangle to the current path.

         *

         * This call starts scope "path".

         * Only other functions for constructing paths can be called in "path"

         * scope, e.g. lineto() or closepath(). None of the graphics state

         * functions or saving/restoring the graphics state, or setting the

         * current color must be used in "path" scope.

         * -------------------------------------------------------------------

         */

        p.rect(200, 200, 250, 150);

        /* --------------------------------------------------------------------

         * Fill the interior of the path with the current fill color.

         *

         * This call terminates scope "path". After this call the current scope

         * will be "page" again.

         * --------------------------------------------------------------------

         */

        p.fill();

        /* Set the current line width. This call is allowed in scope "page". */

        p.setlinewidth(10);

        /* Set the current point for graphics output.

         *

         * This function starts the scope "path".

         */

        p.moveto(100, 500);

        /* Add a line to the current path */

        p.lineto(300, 700);

        /* ---------------------------------------------------------------------

         * Stroke the path with the current line width and current stroke color,

         * and clear it.

         *

         * This function terminates scope "path". After this call the current

         * scope will be "page" again.

         * ---------------------------------------------------------------------

         */

        p.stroke();

        /* --------------------------------------------------------------------

         * Complete the first page.

         *

         * This call terminates scope "page". After this call the current scope

         * will be "document" again.

         * --------------------------------------------------------------------

         */

        p.end_page_ext("");

        /* Close the image. This call could have also be used in scope "page"

         * before ending the page.

         */

        p.close_image(image);

        /* ----------------------------------------------------------------

         * This call terminates scope "document". The current scope will be

         * "object" again

         * ----------------------------------------------------------------

         */

        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");

        } catch (Exception e) {

            System.err.println(e.getMessage());

        } finally {

            if (p != null) {

                p.delete();

            }

        }

    }

}