Image Watermark Function How To Add On the Fly Tutorial

Learn how to apply a watermark to any uploaded images on the fly, by adding another custom function to our image processing library file.

<form enctype="multipart/form-data" method="post" action="image_upload_script.php">
Choose your file here:
<input name="uploaded_file" type="file"/><br /><br />
<input type="submit" value="Upload It"/>
</form>

<?php
// Access the $_FILES global variable for this specific file being uploaded
// and create local PHP variables from the $_FILES array of information
$fileName = $_FILES["uploaded_file"]["name"]; // The file name
$fileTmpLoc = $_FILES["uploaded_file"]["tmp_name"]; // File in the PHP tmp folder
$fileType = $_FILES["uploaded_file"]["type"]; // The type of file it is
$fileSize = $_FILES["uploaded_file"]["size"]; // File size in bytes
$fileErrorMsg = $_FILES["uploaded_file"]["error"]; // 0 for false... and 1 for true
$fileName = preg_replace('#[^a-z.0-9]#i', '', $fileName); // filter
$kaboom = explode(".", $fileName); // Split file name into an array using the dot
$fileExt = end($kaboom); // Now target the last array element to get the file extension

// START PHP Image Upload Error Handling -------------------------------
if (!$fileTmpLoc) { // if file not chosen
    echo "ERROR: Please browse for a file before clicking the upload button.";
    exit();
} else if($fileSize > 5242880) { // if file size is larger than 5 Megabytes
    echo "ERROR: Your file was larger than 5 Megabytes in size.";
    unlink($fileTmpLoc); // Remove the uploaded file from the PHP temp folder
    exit();
} else if (!preg_match("/.(gif|jpg|png)$/i", $fileName) ) {
     // This condition is only if you wish to allow uploading of specific file types    
     echo "ERROR: Your image was not .gif, .jpg, or .png.";
     unlink($fileTmpLoc); // Remove the uploaded file from the PHP temp folder
     exit();
} else if ($fileErrorMsg == 1) { // if file upload error key is equal to 1
    echo "ERROR: An error occured while processing the file. Try again.";
    exit();
}
// END PHP Image Upload Error Handling ---------------------------------
// Place it into your "uploads" folder mow using the move_uploaded_file() function
$moveResult = move_uploaded_file($fileTmpLoc, "uploads/$fileName");
// Check to make sure the move result is true before continuing
if ($moveResult != true) {
    echo "ERROR: File not uploaded. Try again.";
    exit();
}
// Include the file that houses all of our custom image functions
include_once("ak_php_img_lib_1.0.php");
// ---------- Start Universal Image Resizing Function --------
$target_file = "uploads/$fileName";
$resized_file = "uploads/resized_$fileName";
$wmax = 500;
$hmax = 500;
ak_img_resize($target_file, $resized_file, $wmax, $hmax, $fileExt);
// ----------- End Universal Image Resizing Function ----------
// ---------- Start Convert to JPG Function --------
if (strtolower($fileExt) != "jpg") {
    $target_file = "uploads/resized_$fileName";
    $new_jpg = "uploads/resized_".$kaboom[0].".jpg";
    ak_img_convert_to_jpg($target_file, $new_jpg, $fileExt);
}
// ----------- End Convert to JPG Function -----------
// ---------- Start Image Watermark Function --------
$target_file = "uploads/resized_".$kaboom[0].".jpg";
$wtrmrk_file = "watermark.png";
$new_file = "uploads/protected_".$kaboom[0].".jpg";
ak_img_watermark($target_file, $wtrmrk_file, $new_file);
// ----------- End Image Watermark Function -----------
// Display things to the page so you can see what is happening for testing purposes
echo "The file named <strong>$fileName</strong> uploaded successfuly.<br /><br />";
echo "It is <strong>$fileSize</strong> bytes in size.<br /><br />";
echo "It is an <strong>$fileType</strong> type of file.<br /><br />";
echo "The file extension is <strong>$fileExt</strong><br /><br />";
echo "The Error Message output for this upload is: $fileErrorMsg";
?>

<?php
// ----------------------- RESIZE FUNCTION -----------------------
// Function for resizing any jpg, gif, or png image files
function ak_img_resize($target, $newcopy, $w, $h, $ext) {
    list($w_orig, $h_orig) = getimagesize($target);
    $scale_ratio = $w_orig / $h_orig;
    if (($w / $h) > $scale_ratio) {
           $w = $h * $scale_ratio;
    } else {
           $h = $w / $scale_ratio;
    }
    $img = "";
    $ext = strtolower($ext);
    if ($ext == "gif"){ 
    $img = imagecreatefromgif($target);
    } else if($ext =="png"){ 
    $img = imagecreatefrompng($target);
    } else { 
    $img = imagecreatefromjpeg($target);
    }
    $tci = imagecreatetruecolor($w, $h);
    // imagecopyresampled(dst_img, src_img, dst_x, dst_y, src_x, src_y, dst_w, dst_h, src_w, src_h)
    imagecopyresampled($tci, $img, 0, 0, 0, 0, $w, $h, $w_orig, $h_orig);
    if ($ext == "gif"){ 
        imagegif($tci, $newcopy);
    } else if($ext =="png"){ 
        imagepng($tci, $newcopy);
    } else { 
        imagejpeg($tci, $newcopy, 84);
    }
}
// -------------- THUMBNAIL (CROP) FUNCTION ---------------
// Function for creating a true thumbnail cropping from any jpg, gif, or png image files
function ak_img_thumb($target, $newcopy, $w, $h, $ext) {
    list($w_orig, $h_orig) = getimagesize($target);
    $src_x = ($w_orig / 2) - ($w / 2);
    $src_y = ($h_orig / 2) - ($h / 2);
    $ext = strtolower($ext);
    $img = "";
    if ($ext == "gif"){ 
    $img = imagecreatefromgif($target);
    } else if($ext =="png"){ 
    $img = imagecreatefrompng($target);
    } else { 
    $img = imagecreatefromjpeg($target);
    }
    $tci = imagecreatetruecolor($w, $h);
    imagecopyresampled($tci, $img, 0, 0, $src_x, $src_y, $w, $h, $w, $h);
    if ($ext == "gif"){ 
        imagegif($tci, $newcopy);
    } else if($ext =="png"){ 
        imagepng($tci, $newcopy);
    } else { 
        imagejpeg($tci, $newcopy, 84);
    }
}
// ----------------------- IMAGE CONVERT FUNCTION -----------------------
// Function for converting GIFs and PNGs to JPG upon upload
function ak_img_convert_to_jpg($target, $newcopy, $ext) {
    list($w_orig, $h_orig) = getimagesize($target);
    $ext = strtolower($ext);
    $img = "";
    if ($ext == "gif"){ 
        $img = imagecreatefromgif($target);
    } else if($ext =="png"){ 
        $img = imagecreatefrompng($target);
    }
    $tci = imagecreatetruecolor($w_orig, $h_orig);
    imagecopyresampled($tci, $img, 0, 0, 0, 0, $w_orig, $h_orig, $w_orig, $h_orig);
    imagejpeg($tci, $newcopy, 84);
}
// ----------------------- IMAGE WATERMARK FUNCTION -----------------------
// Function for applying a PNG watermark file to a file after you convert the upload to JPG
function ak_img_watermark($target, $wtrmrk_file, $newcopy) { 
    $watermark = imagecreatefrompng($wtrmrk_file); 
    imagealphablending($watermark, false); 
    imagesavealpha($watermark, true); 
    $img = imagecreatefromjpeg($target);
    $img_w = imagesx($img); 
    $img_h = imagesy($img); 
    $wtrmrk_w = imagesx($watermark); 
    $wtrmrk_h = imagesy($watermark); 
    $dst_x = ($img_w / 2) - ($wtrmrk_w / 2); // For centering the watermark on any image
    $dst_y = ($img_h / 2) - ($wtrmrk_h / 2); // For centering the watermark on any image
    imagecopy($img, $watermark, $dst_x, $dst_y, 0, 0, $wtrmrk_w, $wtrmrk_h); 
    imagejpeg($img, $newcopy, 100); 
    imagedestroy($img); 
    imagedestroy($watermark); 
} 
?>