Change the Brightness of a Picture

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Current image taken from images file folder:

Select Brightness (0 = no change, 10 = brightest)

Brightness Determination:

Bright

0   1   2   3   4   5  

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SLAVE CODE FOLLOWS

<?php // brightness script

// this takes an image from a database and changes it's bightness

$brightness = $_GET['br'];

// get the images from files
$image = imagecreatefromjpeg("../images/momo.jpg");

// get the palette from the image and create a 256 color palette
imagetruecolortopalette($image, true, 256);

// find the total number of colors in the palette
$totalColors = imagecolorstotal($image);

//    now cycle through all the colors and change their brightness (see function)
for ($index = 0; $index < $totalColors; $index++)
{
    // $RGB is an array
    $RGB = imagecolorsforindex($image, $index);
    $red = adjustBightness($RGB['red'], $brightness);
    $green = adjustBightness($RGB['green'], $brightness);
    $blue = adjustBightness($RGB['blue'], $brightness);
    imagecolorset($image, $index, $red, $green, $blue);
}

// set the header for the image
header("Content-type: image/jpeg");
imagejpeg($image);
imagedestroy($image);

// ==== functions =======

function adjustBightness($color, $brightness)
{
    // determine the color brightness
    $color += (($brightness / 10) * 255);

    // make sure the color value does not exceed 255
    $color = ($color > 255) ? 255 : $color;
    return $color;
}

?>


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CODE FOLLOWS

<?php
include('includes/header.php');

$self = basename($_SERVER['SCRIPT_NAME']);
$step = isset($_POST['step']) ? $_POST['step'] : 1;
$brightness = isset($_POST['choice']) ? $_POST['choice'] : null;

$s = 'CHECKED';

if (isset($_POST['choice']))
{
    $choice = $_POST['choice'];
}
else
{
    $choice = 0;    // set default here
}
?>

    <h1>
        Change the Brightness of a Picture
    </h1>

<?php

switch ($step)
{

    // STEP 1 ----------------------

    case 1:    //--- get the change of brightness the user wants
        ?>

        <hr>
        <p>
            Current image taken from images file folder:
        </p>

        <img src="../images/momo.jpg" alt="my Dog">

        <p>
            Select Brightness (0 = no change, 10 = brightest)
        </p>

        <form action="<?php echo($self); ?>" method="post">
            <fieldset>
                <legend>Brightness Determination:</legend>
                <label for="choice">Bright</label>
                <br><br>
                <?php
                for ($i = 0; $i <= 5; $i++)
                {
                    ?>

                    <input type="radio" id="choice" name="choice"
                           value="<?php echo($i); ?>"<?php if ($choice == $i) {
                        echo($s);
                    } ?> > <?php echo($i); ?> &nbsp;

                    <?php
                }
                ?>
            </fieldset>
            <br>
            <br>
            <input type="submit" name="submit" value="Submit">
            <input type="hidden" name="step" value="2">
        </form>
        <br>

        <?php
        break;

    // STEP 2 ----------------------

    case 2:    //--- show the brightness

        // provide the user the opportunity to try again
        ?>

        <hr>

        <h3> Brightness: <?php echo($brightness); ?></h3>

        <img src="bright.php?br=<?php echo($brightness); ?> alt="My Bright Dog">

        <br>

        <form action="<?php echo($self); ?>" method="post">
            <input type="hidden" name="step" value="1">
            <input type="submit" value="Try Again">
        </form>

        <br>

        <?php
}
// end of program
// list code for slave routine
echo('<hr><br>SLAVE CODE FOLLOWS<br><br>');
highlight_file('bright.php');
echo('<hr>');

include('includes/footer.php');
?>

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