If you are familiar with PHP's GD library, it is not difficult at all to understand this article!
<?php
/****************************************************** *******************************
Parameter description:
$max_file_size: upload file size limit, unit BYTE
$destination_folder: Upload file path
$watermark: Whether to add a watermark (1 means adding watermark, others means not adding watermark);
Instructions for use:
1. Remove the ; sign in front of the "extension=php_gd2.dll" line in the PHP.INI file, because we need to use the GD library;
2. Change extension_dir = to the directory where your php_gd2.dll is located;
*************************************************** ******************************/
//Upload file type list
$uptypes=array(
'image/jpg',
'image/jpeg',
'image/png',
'image/pjpeg',
'image/gif',
'image/bmp',
'image/x-png'
);
$max_file_size=2000000; //Upload file size limit, unit BYTE
$destination_folder="uploadimg/"; //Upload file path
$watermark=1; //Whether to add a watermark (1 means adding watermark, others means not adding watermark);
$watertype=1; //Watermark type (1 is text, 2 is picture)
$waterposition=1; //Watermark position (1 is the lower left corner, 2 is the lower right corner, 3 is the upper left corner, 4 is the upper right corner, 5 is in the center);
$waterstring=" http://www.xplore.cn/ "; //Watermark string
$waterimg="xplore.gif"; //watermark image
$imgpreview=1; //Whether to generate a preview image (1 means generated, others do not generate);
$imgpreviewsize=1/2; //Thumbnail ratio
?>
<html>
<head>
<title>ZwelL picture upload program</title>
<style type="text/css">
<!--
body
{
font-size: 9pt;
}
input
{
background-color: #66CCFF;
border: 1px inset #CCCCCC;
}
-->
</style>
</head>
<body>
<form enctype="multipart/form-data" method="post" name="upform">
Upload files:
<input name="upfile" type="file">
<input type="submit" value="Upload"><br>
The file types allowed to be uploaded are:<?=implode(', ',$uptypes)?>
</form>
<?php
if ($_SERVER['REQUEST_METHOD'] == 'POST')
{
if (!is_uploaded_file($_FILES["upfile"][tmp_name]))
//Does the file exist?
{
echo "The picture does not exist!";
exit;
}
$file = $_FILES["upfile"];
if($max_file_size < $file["size"])
//check file size
{
echo "The file is too large!";
exit;
}
if(!in_array($file["type"], $uptypes))
//check file type
{
echo "File type does not match!".$file["type"];
exit;
}
if(!file_exists($destination_folder))
{
mkdir($destination_folder);
}
$filename=$file["tmp_name"];
$image_size = getimagesize($filename);
$pinfo=pathinfo($file["name"]);
$ftype=$pinfo['extension'];
$destination = $destination_folder.time().".".$ftype;
if (file_exists($destination) && $overwrite != true)
{
echo "The file with the same name already exists";
exit;
}
if(!move_uploaded_file ($filename, $destination))
{
echo "Error moving file";
exit;
}
$pinfo=pathinfo($destination);
$fname=$pinfo[basename];
echo " <font color=red>Uploaded successfully</font><br>File name: <font color=blue>".$destination_folder.$fname."</font><br>";
echo "Width:".$image_size[0];
echo "length:".$image_size[1];
echo "<br> size:".$file["size"]." bytes";
if($watermark==1)
{
$iinfo=getimagesize($destination,$iinfo);
$nimage=imagecreatetruecolor($image_size[0],$image_size[1]);
$white=imagecolorallocate($nimage,255,255,255);
$black=imagecolorallocate($nimage,0,0,0);
$red=imagecolorallocate($nimage,255,0,0);
imagefill($nimage,0,0,$white);
switch ($iinfo[2])
{
case 1:
$simage =imagecreatefromgif($destination);
break;
case 2:
$simage =imagecreatefromjpeg($destination);
break;
case 3:
$simage =imagecreatefrompng($destination);
break;
case 6:
$simage =imagecreatefromwbmp($destination);
break;
default:
die("Unsupported file type";
exit;
}
imagecopy($nimage,$simage,0,0,0,0,$image_size[0],$image_size[1]);
imagefilledrectangle($nimage,1,$image_size[1]-15,80,$image_size[1],$white);
switch($watertype)
{
case 1: //Add watermark string
imagestring($nimage,2,3,$image_size[1]-15,$waterstring,$black);
break;
case 2: //Add watermark image
$simage1 =imagecreatefromgif("xplore.gif";
imagecopy($nimage,$simage1,0,0,0,0,85,15);
imagedestroy($simage1);
break;
}
switch ($iinfo[2])
{
case 1:
//imagegif($nimage, $destination);
imagejpeg($nimage, $destination);
break;
case 2:
imagejpeg($nimage, $destination);
break;
case 3:
imagepng($nimage, $destination);
break;
case 6:
imagewbmp($nimage, $destination);
//imagejpeg($nimage, $destination);
break;
}
//Overwrite the original uploaded file
imagedestroy($nimage);
imagedestroy($simage);
}
if($imgpreview==1)
{
echo "<br>Picture preview:<br>";
echo "<img src="".$destination."" width=".($image_size[0]*$imgpreviewsize)." height=".($image_size[1]*$imgpreviewsize);
echo " alt="Picture preview:rFile name:".$destination."rUpload time:">";
}
}
?>
</body>
</html>
Finally, I think it is necessary to talk about the principle of watermarking images:
getting the uploaded file information, creating a true color image, assigning a color scheme and filling the image.
Create a graphic by judging the file type, then copy it to the originally created graphic, fill in and create a rectangle, ready to be written to imagestring() or the original image
program to determine the watermark type: one is a string, the other is Add a graphics object on top.