Change the Brightness of a Picture

Current image taken from images file folder:

my Dog

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

Brightness Determination:

0   1   2   3   4   5  



NOTE: The instructions below are NOT part of your assignment. As such, they do not need to be included in your final page.

Your assignment:

Create a form that works as this one does.

Note this is a TWO STEP Form operation:

Form Step 1

Show the image (taken directly from the filesystem with sticky radio buttons ranging from 0 to 10. These radio buttons will allow the user to select the degree of brightness they want to apply to the image and then click Submit.

Form Step 2

Send the script Brightness values via a GET to the image slave brightness script (see below). This script ("bright.php"): 1) gets the image from the file system; 2) adjust the brightness of the image; 3) and then displays the image in part two of the form.

Also, provide the user with the option to do it again.


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/baby.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;
        }

?>
 
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/baby.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>

                <hr>

                <p class="red">
                    NOTE: The instructions below are NOT part of your assignment. As such, they do not
                    need to be included in your final page.
                </p>

                <h2>
                    Your assignment:
                </h2>

                <p>
                    Create a form that works as this one does.
                </p>

                <ul>
                    <li>The Sticky Radio Example;</li>
                    <li>AND the Two Step Form from that Example;</li>
                    <li>The slave script is listed below. You don't need to alter the code,
                        just use it correctly "as-is".
                    </li>
                </ul>

                <h2>
                    Note this is a TWO STEP Form operation:
                </h2>
                <p>
                    Form Step 1
                </p>
                <p>
                    Show the image (taken directly from the filesystem with sticky radio buttons ranging from 0 to 10.
                    These radio buttons will allow the user to select the degree of brightness they want to apply to
                    the image and then click Submit.
                </p>
                <p>
                    Form Step 2
                </p>
                <p>
                    Send the script Brightness values via a GET to the image slave brightness script (see below).
                    This script ("bright.php"): 1) gets the image from the file system; 2) adjust the brightness
                    of the image; 3) and then displays the image in part two of the form.
                </p>
                <p>
                    Also, provide the user with the option to do it again.
                </p>

                <?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
                break;
        }

    // 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');
?>