Example of image proportional scaling in PHP

PHP image proportional scaling instance. For more information, see The code is as follows:
// Proportional scaling of the image

// Because PHP can only operate on resources, you need to copy the image to be scaled and create a new resource.
$Src?imagecreatefrom=('a.jpg ');

// Obtain the width and height of the source image
$Size_src1_getimagesize('a.jpg ');
$ W = $ size_src ['0'];
$ H = $ size_src ['1'];

// Specify the scaled width (or the height)
$ Max = 300;

// Calculate the length of the other side based on the maximum value of 300 to obtain the scaled image width and height.
If ($ w> $ h ){
$ W = $ max;
$ H = $ h * ($ max/$ size_src ['0']);
} Else {
$ H = $ max;
$ W = $ w * ($ max/$ size_src ['1']);
}


// Declare a $ w width, $ h high real color image resource
$ Image = imagecreatetruecolor ($ w, $ h );


// Key functions, parameters (start coordinates x and y of the target resource, source resource, and target resource, and start coordinates x and y of the source resource, w, h, SOURCE Resource width/height w, h)
Imagecopyresampled ($ image, $ src, 0, 0, 0, $ w, $ h, $ size_src ['0'], $ size_src ['1']);

// Tell the browser to parse the image
Header ('content-type: image/png ');
Imagepng ($ image );

// Destroy resources
Imagedestroy ($ image );

?>