


PHP image cropping function (keeping the image unchanged)_PHP tutorial
In order to automatically crop the image after uploading, and then display the cropped image in the foreground.
The requirements are as above and the source code is as follows:
*exif_imagetype -- Determine the type of an image
*Description: The function is to crop an image into an image of any size without deformation of the image
* Parameter description: Enter 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
*/
// Obtain an image of any size, stretch the insufficient areas without deformation , Leave a blank Function My_image_resize ($ SRC_FILE, $ DST_FILE, $ New_width, $ New_height) {
$ New_width = INTVAL ($ new_width);
$ NE w_height = intval ($ new_width);
If ($ new_width & lt; 1 || $ new_height & lt; 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); s Type of Image Does Not Support! Only support jpg, gif or png";
exit();
}
//Load image
switch($type) {
case IMAGETYPE_JPEG:
$s rc_img=imagecreatefromjpeg($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;
$ratio=1.0;
// The aspect ratio of the generated image is the original They are all small or large, the principle is to increase the large proportion, and the large proportion of reduction (the reduction ratio is relatively small)
if (($ Ratio_w & LT; 1 && $ raatio_h & lt; 1) || ($ Ratio_w >1 Use the ratio standard to crop or enlarge
}else {
$ratio = $ratio_w ;
}
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 size of the target image $ratio ratio
// Define a new image
new_width, $new_height); inter_h);
switch($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,$dst_file,100);
break;
. ;
( ($ratio_w 1) || ($ratio_w >1 && $ratio_h else{
$ratio=$ratio_h>$ratio_w? $ratio_h : $ratio_w; //Take the value with the larger ratio
// Define a large middle image whose height or width 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, $inter_h);
//Crop the original image after scaling
imagecopyresampled($inter_img,$src_img,0,0,0,0,$inter_w,$inter_h,$w,$h);
$new_width,$new_height);
imagecopy($new_img, $inter_img, 0,0,0,0,$new_width,$new_height);
switch($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;
}
}// if3
}// end function
my_image_resize('test.gif','11111.gif','100px','100px');
?>

Calculating the total number of elements in a PHP multidimensional array can be done using recursive or iterative methods. 1. The recursive method counts by traversing the array and recursively processing nested arrays. 2. The iterative method uses the stack to simulate recursion to avoid depth problems. 3. The array_walk_recursive function can also be implemented, but it requires manual counting.

In PHP, the characteristic of a do-while loop is to ensure that the loop body is executed at least once, and then decide whether to continue the loop based on the conditions. 1) It executes the loop body before conditional checking, suitable for scenarios where operations need to be performed at least once, such as user input verification and menu systems. 2) However, the syntax of the do-while loop can cause confusion among newbies and may add unnecessary performance overhead.

Efficient hashing strings in PHP can use the following methods: 1. Use the md5 function for fast hashing, but is not suitable for password storage. 2. Use the sha256 function to improve security. 3. Use the password_hash function to process passwords to provide the highest security and convenience.

Implementing an array sliding window in PHP can be done by functions slideWindow and slideWindowAverage. 1. Use the slideWindow function to split an array into a fixed-size subarray. 2. Use the slideWindowAverage function to calculate the average value in each window. 3. For real-time data streams, asynchronous processing and outlier detection can be used using ReactPHP.

The __clone method in PHP is used to perform custom operations when object cloning. When cloning an object using the clone keyword, if the object has a __clone method, the method will be automatically called, allowing customized processing during the cloning process, such as resetting the reference type attribute to ensure the independence of the cloned object.

In PHP, goto statements are used to unconditionally jump to specific tags in the program. 1) It can simplify the processing of complex nested loops or conditional statements, but 2) Using goto may make the code difficult to understand and maintain, and 3) It is recommended to give priority to the use of structured control statements. Overall, goto should be used with caution and best practices are followed to ensure the readability and maintainability of the code.

In PHP, data statistics can be achieved by using built-in functions, custom functions, and third-party libraries. 1) Use built-in functions such as array_sum() and count() to perform basic statistics. 2) Write custom functions to calculate complex statistics such as medians. 3) Use the PHP-ML library to perform advanced statistical analysis. Through these methods, data statistics can be performed efficiently.

Yes, anonymous functions in PHP refer to functions without names. They can be passed as parameters to other functions and as return values of functions, making the code more flexible and efficient. When using anonymous functions, you need to pay attention to scope and performance issues.


Hot AI Tools

Undresser.AI Undress
AI-powered app for creating realistic nude photos

AI Clothes Remover
Online AI tool for removing clothes from photos.

Undress AI Tool
Undress images for free

Clothoff.io
AI clothes remover

Video Face Swap
Swap faces in any video effortlessly with our completely free AI face swap tool!

Hot Article

Hot Tools

VSCode Windows 64-bit Download
A free and powerful IDE editor launched by Microsoft

Notepad++7.3.1
Easy-to-use and free code editor

SAP NetWeaver Server Adapter for Eclipse
Integrate Eclipse with SAP NetWeaver application server.

SublimeText3 Mac version
God-level code editing software (SublimeText3)

ZendStudio 13.5.1 Mac
Powerful PHP integrated development environment
