How to use PHP to set image watermark and save it

PHP (Hypertext Preprocessor) is a popular server-side scripting language used to create dynamic websites and web applications. In developing web applications, image watermarks are usually one of the important features, which can protect the copyright of images while increasing their artistry and beauty. In this article, I will introduce how to use PHP to set image watermarks and save them.

Step one: Get the picture

First, we need to get the picture to be added with a watermark. You can use the "imagecreatefromjpeg", "imagecreatefrompng" and other functions in PHP to get it from different picture formats Image resources. For example, the following is a sample code for obtaining image resources from a JPEG file:

$source = imagecreatefromjpeg('image.jpg');

Step 2: Create a watermark

Next, we need to create the watermark to be added. You can use "imagecreatefromjpeg", "imagecreatefrompng" and other functions in PHP to obtain image resources from different image formats as watermarks. For example, here is the sample code to get the watermark from the PNG file:

$watermark = imagecreatefrompng('watermark.png');

Step 3: Add the watermark to the image

We can use the "imagecopy" function to add the watermark to the image . This function requires specifying the source and destination images, as well as the location of the source image and the location of the destination image. For example, here is the sample code to add a watermark to the original image:

$watermark_width = imagesx($watermark);
$watermark_height = imagesy($watermark);
$dest_x = imagesx($source) - $watermark_width - 10;
$dest_y = imagesy($source) - $watermark_height - 10;
imagecopy($source, $watermark, $dest_x, $dest_y, 0, 0, $watermark_width, $watermark_height);

In the above code, we first get the width and height of the watermark, and then calculate the position of the watermark in the original image. Then use the "imagecopy" function to add the watermark to the original image, specifying the source and destination locations.

Step 4: Save the image

Finally, we need to save the watermarked image to the server. You can use functions such as "imagejpeg" and "imagepng" to save image resources into different formats such as JPEG and PNG. For example, the following is a sample code to save a watermarked image into JPEG format:

imagejpeg($source, 'result.jpg');

In the above code, we use the "imagejpeg" function to save the image resource into JPEG format and specify the saved file Named "result.jpg".

The complete code is as follows:

$source = imagecreatefromjpeg('image.jpg');
$watermark = imagecreatefrompng('watermark.png');

$watermark_width = imagesx($watermark);
$watermark_height = imagesy($watermark);
$dest_x = imagesx($source) - $watermark_width - 10;
$dest_y = imagesy($source) - $watermark_height - 10;
imagecopy($source, $watermark, $dest_x, $dest_y, 0, 0, $watermark_width, $watermark_height);

imagejpeg($source, 'result.jpg');

Conclusion

Through the above steps, we can easily use PHP to set image watermarks and save them. Of course, this article is just a simple example, and more details and optimizations may need to be considered in actual applications. Therefore, in actual applications, please make corresponding modifications and optimizations according to your needs.

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