Technology sharing: PHP image operation functions

With the popularity of the Internet, web page production has become a new culture and trend. Image manipulation has also become an important part of web page production. As one of the most popular web programming languages, PHP provides a wealth of image operation functions to meet various image processing needs. In this article, we will introduce some commonly used PHP image manipulation functions and their usage.

1. imagecreatefromjpeg()

This function can read image files in JPEG format and convert them into image resources. Its usage is as follows:

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

Among them, example.jpg is the image file path in JPEG format.

2. imagecreatefrompng()

This function can read image files in PNG format and convert them into image resources. Its usage is similar to the imagecreatefromjpeg() function.

$image = imagecreatefrompng('example.png');

3. imagecreatefromgif()

This function can read image files in GIF format and convert them into image resources. Its usage is similar to the imagecreatefromjpeg() function.

$image = imagecreatefromgif('example.gif');

4. imagecreatetruecolor()

This function can create a true color image resource of a specified size. Its usage is as follows:

$image = imagecreatetruecolor($width, $height);

Among them, $width and $height are the width and height of the image.

5. imagecopy()

This function can copy part or all of an image to another image. Its usage is as follows:

imagecopy($destination, $source, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h);

Among them, $destination is the target image resource, $source is the source image resource, $dst_x and $dst_y are the starting coordinates of the target image, $src_x and $src_y are the starting coordinates of the source image. Starting coordinates, $src_w and $src_h are the width and height of the source image.

6. imagejpeg()

This function can save image resources as JPEG format files. Its usage is as follows:

imagejpeg($image, 'example.jpg');

Among them, $image is the image resource, and 'example.jpg' is the saved file path.

7. imagepng()

This function can save image resources into PNG format files. Its usage is similar to the imagejpeg() function.

8. imagegif()

This function can save image resources into GIF format files. Its usage is similar to the imagejpeg() function.

9. imagescale()

This function can scale the image according to the specified ratio. Its usage is as follows:

$new_image = imagescale($image, $new_width, $new_height);

Among them, $image is the image resource to be scaled, $new_width and $new_height are the width and height after scaling.

10. imagedestroy()

This function can release the memory occupied by image resources. Its usage is as follows:

imagedestroy($image);

Among them, $image is the image resource to be released.

The above are some commonly used PHP image operation functions and their usage. By mastering these functions, you can easily achieve various image processing effects, enrich web content, and improve user experience.

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