PHP image cropping function_PHP tutorial-PHP Tutorial-php.cn

PHP image cropping function_PHP tutorial

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Release： 2016-07-13 10:30:36

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This article mainly introduces the PHP image cropping function while keeping the image unchanged. Friends in need can refer to it

In order to automatically crop the image after uploading it, and then display the cropped image in the foreground.

The requirements are as above and the source code is as follows:

The code is as follows:

*exif_imagetype -- Determine the type of an image

*Description: The function is to crop an image to an image of any size without deforming the image

* Parameter description: Input the file name of the image to be processed, generate the save file name of the new image, generate the width of the new image, and generate the height of the new image

// Get an image of any size, stretch the missing parts without deformation, and leave no blank spaces

function my_image_resize($src_file, $dst_file , $new_width , $new_height) {

$new_width= intval($new_width);

$new_height=intval($new_width);

if($new_width <1 || $new_height <1) {

echo "params width or height error !";

exit();

}

if(!file_exists($src_file)) {

echo $src_file . " is not exists !";

exit();

}

//Image type

$type=exif_imagetype($src_file);

$support_type=array(IMAGETYPE_JPEG , IMAGETYPE_PNG , IMAGETYPE_GIF);

if(!in_array($type, $support_type,true)) {

echo "this type of image does not support! only support jpg , gif or png";

exit();

}

//Load image

switch($type) {

case IMAGETYPE_JPEG :

$src_img=imagecreatefromjpeg($src_file);

break;

case IMAGETYPE_PNG :

$src_img=imagecreatefrompng($src_file);

break;

case IMAGETYPE_GIF :

$src_img=imagecreatefromgif($src_file);

break;

default:

echo "Load image error!";

exit();

}

$w=imagesx($src_img);

$h=imagesy($src_img);

$ratio_w=1.0 * $new_width / $w;

$ratio_h=1.0 * $new_height / $h;

$ratio=1.0;

// The height and width of the generated image are smaller or larger than the original ones. The principle is to enlarge by a large ratio and reduce by a large ratio (the reduced ratio will be smaller)

if( ($ratio_w < 1 && $ratio_h < 1) || ($ratio_w > 1 && $ratio_h > 1)) {

if($ratio_w < $ratio_h) {

$ratio = $ratio_h ; // Case 1, the width ratio is smaller than the height direction, crop or enlarge according to the height ratio standard

}else {

$ratio = $ratio_w ;

}

// Define an intermediate temporary image whose aspect ratio exactly meets the target requirements

$inter_w=(int)($new_width / $ratio);

$inter_h=(int) ($new_height / $ratio);

$inter_img=imagecreatetruecolor($inter_w , $inter_h);

//var_dump($inter_img);

imagecopy($inter_img, $src_img, 0,0,0,0,$inter_w,$inter_h);

// Generate a temporary image with the maximum side length as the target image $ratio ratio

//Define a new image

$new_img=imagecreatetruecolor($new_width,$new_height);

//var_dump($new_img);exit();

imagecopyresampled($new_img,$inter_img,0,0,0,0,$new_width,$new_height,$inter_w,$inter_h);

switch($type) {

case IMAGETYPE_JPEG :

imagejpeg($new_img, $dst_file,100); // Store image

break;

case IMAGETYPE_PNG :

imagepng($new_img,$dst_file,100);

break;

case IMAGETYPE_GIF :

imagegif($new_img,$dst_file,100);

break;

default:

break;

}

} // end if 1

// 2 One side of the target image is larger than the original image, and one side is smaller than the original image. First enlarge the ordinary image, and then crop it

// =if( ($ratio_w < 1 && $ratio_h > 1) || ($ratio_w >1 && $ratio_h <1) )

else{

$ratio=$ratio_h>$ratio_w? $ratio_h : $ratio_w; //Take the value with the larger ratio

// Define a large image in the middle, the height or width of the image is equal to the target image, and then enlarge the original image

$inter_w=(int)($w * $ratio);

$inter_h=(int) ($h * $ratio);

$inter_img=imagecreatetruecolor($inter_w , $inter_h);

// Scale the original image and then crop it

imagecopyresampled($inter_img,$src_img,0,0,0,0,$inter_w,$inter_h,$w,$h);

//Define a new image

$new_img=imagecreatetruecolor($new_width,$new_height);

imagecopy($new_img, $inter_img, 0,0,0,0,$new_width,$new_height);