PHP水印 [英] PHP watermarking
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问题描述
我正在使用此代码创建水印。
i am using this code to create watermark.
$image = '1.jpg';
$overlay = 'stamp.png';
$opacity = "20";
if (!file_exists($image)) {
die("Image does not exist.");
}
// Set offset from bottom-right corner
$w_offset = 0;
$h_offset = 100;
$extension = strtolower(substr($image, strrpos($image, ".") + 1));
// Load image from file
switch ($extension)
{
case 'jpg':
$background = imagecreatefromjpeg($image);
break;
case 'jpeg':
$background = imagecreatefromjpeg($image);
break;
case 'png':
$background = imagecreatefrompng($image);
break;
case 'gif':
$background = imagecreatefromgif($image);
break;
default:
die("Image is of unsupported type.");
}
// Find base image size
$swidth = imagesx($background);
$sheight = imagesy($background);
// Turn on alpha blending
imagealphablending($background, true);
// Create overlay image
$overlay = imagecreatefrompng($overlay);
// Get the size of overlay
$owidth = imagesx($overlay);
$oheight = imagesy($overlay);
// Overlay watermark
imagecopymerge($background, $overlay, $swidth - $owidth - $w_offset, $sheight - $oheight - $h_offset, 0, 0, $owidth, $oheight, $opacity);
imagejpeg($background,$image);
// Destroy the images
imagedestroy($background);
imagedestroy($overlay);
png图像包含一个文本,其他所有区域都是透明的。
但是当我执行这段代码时,它会将png应用于jpg,但是没有保持png的透明度。它显示在一个方框中。
the png image contains a text with all other region as transparent. but when i execute this code , it applys the png over jpg, but the transparecy is not maintained of the png. it shows in a box.
我怎样才能实现这一目标。即如果一个png包含透明部分,它应该在该部分显示下面的图像....?
how can i acheive that . ie if a png contains transaparent part , it should show the below image in that part....?
推荐答案
替换imagecopymerge imagecopy解决了这个问题。这是新代码
replacing imagecopymerge with imagecopy solved the issue. here is the new code
function watermark($image){
$overlay = '../../../photos/photosets/stamp.png';
$opacity = "20";
if (!file_exists($image)) {
die("Image does not exist.");
}
// Set offset from bottom-right corner
$w_offset = 0;
$h_offset = 100;
$extension = strtolower(substr($image, strrpos($image, ".") + 1));
// Load image from file
switch ($extension)
{
case 'jpg':
$background = imagecreatefromjpeg($image);
break;
case 'jpeg':
$background = imagecreatefromjpeg($image);
break;
case 'png':
$background = imagecreatefrompng($image);
break;
case 'gif':
$background = imagecreatefromgif($image);
break;
default:
die("Image is of unsupported type.");
}
// Find base image size
$swidth = imagesx($background);
$sheight = imagesy($background);
// Turn on alpha blending
imagealphablending($background, true);
// Create overlay image
//$overlay = imagecreatefrompng($overlay);
// Get the size of overlay
$owidth = imagesx($overlay);
$oheight = imagesy($overlay);
$photo = imagecreatefromjpeg($image);
$watermark = imagecreatefrompng($overlay);
// This is the key. Without ImageAlphaBlending on, the PNG won't render correctly.
imagealphablending($photo, true);
// Copy the watermark onto the master, $offset px from the bottom right corner.
$offset = 10;
imagecopy($photo, $watermark, imagesx($photo) - imagesx($watermark) - $offset, imagesy($photo) - imagesy($watermark) - $offset, 0, 0, imagesx($watermark), imagesy($watermark));
// Output to the browser
header("Content-Type: image/jpeg");
imagejpeg($photo,$image);
// Overlay watermark
// Destroy the images
imagedestroy($background);
imagedestroy($overlay);
}
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