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color/color_gradient

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<?php
/* $Id: color_gradient.php,v 1.9 2016/12/09 13:37:41 stm Exp $
 * Color gradient:
 * Fill some area or text with a smooth transition from one color to another

 * Required software: PDFlib/PDFlib+PDI/PPS 9
 * Required data: none
 */

/* This is where the data files are. Adjust as necessary. */
$searchpath = dirname(dirname(dirname(__FILE__)))."/input";
$outfile = "";
$title = "Color Gradient";
$fontsize = 36;

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");
    $p->set_option("stringformat=utf8");

    if ($p->begin_document($outfile, "destination={type=fitwindow}") == 0)
        throw new Exception("Error: " . $p->get_errmsg());

    $p->set_info("Creator", "PDFlib Cookbook");
    $p->set_info("Title", $title);

    /* Start Page */
    $p->begin_page_ext(595, 842, "");

    /*
     * Fill the page completely with a gradient from green to black:
     * 
     * Set the first color for the gradient to green with option
     * 'startcolor'.
     * 
     * The second color for the gradient is set to black using the
     * parameters c1/c2/c3.
     * 
     * Note that starting with PDFlib 9.1 the final color of the
     * gradient can also set via the new option 'endcolor'.
     * The call would then look like this:
     * 
     * $sh = $p->shading("axial", 0, 0, 595, 842, 0.0, 0.0, 0.0, 0.0,
     *     "startcolor={rgb 0.0 0.5 0.5} endcolor={rgb 0 0 0}");
     *     
     * The parameters c1/c2/c3/c4 are ignored in this case.
     */
    $sh = $p->shading("axial", 0, 0, 595, 842, 0.0, 0.0, 0.0, 0.0,
		    "startcolor={rgb 0.0 0.5 0.5}");

    /* Draw the gradient over the whole page */
    $p->shfill($sh);

    /*
     * Fill a rectangle with a gradient:
     * 
     * Set the first color for the gradient to orange.
     * Set the second color for the gradient to a light orange.
     * Define an axial gradient with a size similar to the size of the
     * rectangle to be filled.
     * Create a shading pattern.
     */
    $sh = $p->shading("axial", 200, 200, 450, 450, 0.9, 0.8, 0.8, 0.0,
		    "startcolor={rgb 1.0 0.5 0.1}");
    $pattern = $p->shading_pattern($sh, "");

    /*
     * Draw a rectangle using the shading pattern as fill color.
     */
    $p->set_graphics_option("fillcolor={pattern $pattern}");
    $p->rect(200, 200, 250, 250);
    $p->fill();

    /*
     * Fill a circle with a gradient:
     * 
     * Set the first color for the gradient to white.
     * Set the second color for the gradient to orange.
     * Define a radial gradient with a size similar to the size
     * of the circle to be filled.
     * Create a shading pattern.
     */
    $sh = $p->shading("radial", 400, 600, 400, 600, 1.0, 0.5, 0.1, 0.0,
        "r0=0 r1=60 startcolor={rgb 1.0 1.0 1.0}");
    $pattern = $p->shading_pattern($sh, "");
    
    /*
     * Draw a circle using the shading pattern as fill color.
     */
    $p->set_graphics_option("fillcolor={pattern $pattern}");
    $p->circle(400, 600, 50);
    $p->fill();

    /* Fill a text with a gradient:
     * Load the font.
     */
    $font = $p->load_font("Helvetica-Bold", "unicode", "");

    if ($font == 0)
        throw new Exception("Error: " . $p->get_errmsg());

    /*
     * Set the first color for the gradient to white.
     * Set the second color for the gradient to orange.
     * Define an axial gradient with a size similar to the size of
     * the text to be filled.
     * Create a shading pattern.
     */
    $sh = $p->shading("axial", 50, 50, 50, 200, 1.0, 0.5, 0.1, 0.0,
            "startcolor={rgb 1.0 1.0 1.0}");
    $pattern = $p->shading_pattern($sh, "");
    
    /*
     * Option list to use the shading pattern as the fill color
     * for the text. Also specify font and font size.
     */
    $optlist = "fillcolor={pattern $pattern} font=$font fontsize=$fontsize";
    
    /*
     * Output the text with the shading pattern as current fill color.
     */
    $p->fit_textline("Hello World!", 50, 100, $optlist);
    $p->fit_textline("(says PDFlib GmbH)", 50, 100 - $fontsize, $optlist);
    $p->end_page_ext("");

    $p->end_document("");
    $buf = $p->get_buffer();
    $len = strlen($buf);

    header("Content-type: application/pdf");
    header("Content-Length: $len");
    header("Content-Disposition: inline; filename=color_gradient.pdf");
    print $buf;

} catch (PDFlibException $e) {
    echo("PDFlib exception occurred:\n".
        "[" . $e->get_errnum() . "] " . $e->get_apiname() .
        ": " . $e->get_errmsg() . "\n");
    exit(1);
} catch (Exception $e) {
    echo($e->getMessage());
    exit(1);
}

$p = 0;
?>