Uses GD Library to create a progress bar. The bar itself is filled with a gradient. Nice!

gradient-filled-progress-bar.php

<?php

/**
 * Available GET parameters:
 *
 * == COLORS ==
 * bg_r - Red component of bar background color
 * bg_g - Green component of bar background color
 * bg_b - Blue component of bar background color
 * from_r - Red component of gradient start
 * from_g - Green component of gradient start
 * from_b - Blue component of gradient start
 * from_g - Green component of gradient start
 * to_r - Red component of gradient end
 * to_b - Blue component of gradient end
 * to_g - Green component of gradient end
 *
 * == DIMENSIONS ==
 * width - Total width of progress bar
 * height - Total height of progress bar
 *
 * == PROGRESS DATA ==
 * total - Total number of units available. Defaults to 2000.
 * sold - Can come from GET but should come from database.
 *
 */

/* Get color values */
$ob_r   = isset($_GET['bg_r'])   ? $_GET['bg_r']   : 66;  // red component of background color
$ob_g   = isset($_GET['bg_g'])   ? $_GET['bg_g']   : 48;  // green component of background color
$ob_b   = isset($_GET['bg_b'])   ? $_GET['bg_b']   : 32;  // blue component of background color
$from_r = isset($_GET['from_r']) ? $_GET['from_r'] : 212; // red component of gradient start
$from_g = isset($_GET['from_g']) ? $_GET['from_g'] : 169; // green component of gradient start
$from_b = isset($_GET['from_b']) ? $_GET['from_b'] : 0;   // blue component of gradient start
$to_r   = isset($_GET['to_r'])   ? $_GET['to_r']   : 255; // red component of gradient end
$to_g   = isset($_GET['to_g'])   ? $_GET['to_g']   : 212; // blue component of gradient end
$to_b   = isset($_GET['to_b'])   ? $_GET['to_b']   : 0;   // green component of gradient end

/* Get dimension values */
$sold            = isset($_GET['sold'])    ? $_GET['sold']    : 1500; // current number of units sold (or perhaps fundraising $$ achieved) - should actually come from database on live installation
$total           = isset($_GET['total'])   ? $_GET['total']   : 2000; // total number of units available (or perhaps fundraising goal)
$canvas_width    = isset($_GET['width'])   ? $_GET['width']   : 850; // total width of progress bar canvas
$outer_width     = isset($_GET['width'])   ? $_GET['width']   : 850; // total width of progress bar
$canvas_height   = isset($_GET['height'])  ? $_GET['height']  : 40; // total height of progress bar canvas
$outer_height    = isset($_GET['height'])  ? $_GET['height']  : 40; // total height of progress bar
$gradient_height = isset($_GET['height'])  ? $_GET['height']  : 40; // height of progress meter
$gradient_pct    = ($sold / $total); // calculate current sales percentage of total (.25)
$gradient_width  = $gradient_pct * $canvas_width; // calculate gradient percentage of canvas (total width of progress meter)

gradient($canvas_width, $canvas_height, $outer_width, $outer_height, $gradient_width, $gradient_height, $ob_r, $ob_b, $ob_g, $from_r, $from_g, $from_b, $to_r, $to_g, $to_b);

function gradient($canvas_width, $canvas_height, $outer_width, $outer_height, $gradient_width, $gradient_height, $ob_r, $ob_b, $ob_g, $c1_r, $c1_g, $c1_b, $c2_r, $c2_g, $c2_b) {
    // make sure that the parameters are what we need them to be
    $canvas_width       =       intval($canvas_width);
    $canvas_height      =       intval($canvas_height);
    $outer_width        =       intval($outer_width); // outer rectangle width
    $outer_height       =       intval($outer_height); // outer rectangle height
    $gradient_width     =       intval($gradient_width); // inner rectanble width
    $gradient_height    =       intval($gradient_height); // inner rectanble height
    $ob_r               =       intval($ob_r); // outer rectangle bg color
    $ob_g               =       intval($ob_g); // outer rectangle bg color
    $ob_b               =       intval($ob_b); // outer rectangle bg color
    $c1_r               =       intval($c1_r); // inner rectangle starting color
    $c1_g               =       intval($c1_g); // inner rectangle starting color
    $c1_b               =       intval($c1_b); // inner rectangle starting color
    $c2_r               =       intval($c2_r); // inner rectangle ending color
    $c2_g               =       intval($c2_g); // inner rectangle ending color
    $c2_b               =       intval($c2_b); // inner rectangle ending color

    // create outermost image object (canvas)
    $image = imagecreatetruecolor($canvas_width, $canvas_height);

    // create progress bar background
    $outer_bg = imagecolorallocate($image, $ob_r, $ob_g, $ob_b);
    imagefilledrectangle($image, 0, 0, $outer_width, $outer_height, $outer_bg);

    // render gradient step by step
    for($i=0; $i<$gradient_height; $i++) {
        if($i<$gradient_height/2) {
            // get each color component for the first half of the gradient
            $color_r = floor($i * ($c2_r-$c1_r) / $gradient_height*2)+$c1_r;
            $color_g = floor($i * ($c2_g-$c1_g) / $gradient_height*2)+$c1_g;
            $color_b = floor($i * ($c2_b-$c1_b) / $gradient_height*2)+$c1_b;
            // create our color
            $color = imagecolorallocate($image, $color_r, $color_g, $color_b);
            // draw a line using our color
            imagefilledrectangle($image, 0, $i, $gradient_width, $i, $color);
        } else {
            // get each color component for the second half of the gradient
            $color_r = floor(($gradient_height-$i) * ($c2_r-$c1_r) / $gradient_height*2)+$c1_r;
            $color_g = floor(($gradient_height-$i) * ($c2_g-$c1_g) / $gradient_height*2)+$c1_g;
            $color_b = floor(($gradient_height-$i) * ($c2_b-$c1_b) / $gradient_height*2)+$c1_b;
            // create our color
            $color = imagecolorallocate($image, $color_r, $color_g, $color_b);
            // draw a line using our color
            imagefilledrectangle($image, 0, $i, $gradient_width, $i, $color);
        }
    }

    // output the image
    header('Content-type: image/png'); // set headers
    imagepng($image); // or imagejpeg, imagegif..
    imagedestroy($image); // free memory
}

usage-example.html

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>Status Bar</title>
</head>

<body>

    <h2>Sales Goals Progress Bar:</h2>
    <img src="http://foobar.com/gradient.php" />

</body>
</html>