How to rotate and flip images using PHP

How to use PHP to rotate and flip images

Introduction:
In modern Internet applications, image manipulation has become an indispensable function . This article will introduce how to use PHP to rotate and flip images, and attach code examples.

1. Image rotation
Image rotation refers to rotating the image according to a certain angle. To achieve image rotation, we can use PHP's GD library.

1. The first step is to ensure that the GD library has been installed on the server. Enter the following command in the terminal to check whether the GD library has been installed:

php -i | grep -i gd

2. Next, we need to create a PHP function with rotation function. The following is an example function for rotating an image according to a specified angle:

function rotateImage($sourcePath, $angle, $destinationPath) {
    $sourceImage = imagecreatefromjpeg($sourcePath);
    $rotatedImage = imagerotate($sourceImage, $angle, 0);
    imagejpeg($rotatedImage, $destinationPath);
}

In this function, the $sourcePath parameter represents the original image path, the $angle parameter represents the rotation angle, and the $destinationPath parameter represents The output path of the rotated image.

3. Finally, we only need to call this function to rotate the image. The following is an example call:

$sourcePath = 'path/to/source/image.jpg';
$destinationPath = 'path/to/destination/image.jpg';
$angle = 90;

rotateImage($sourcePath, $angle, $destinationPath);

In this example, we rotate the original image 90 degrees and save the rotated image to the target path.

2. Picture flipping
Picture flipping refers to the operation of flipping the picture horizontally or vertically. Similarly, we can use PHP's GD library to achieve image flipping.

1. First, make sure the GD library is installed on the server. Similarly, enter the following command in the terminal to check whether the GD library has been installed:

php -i | grep -i gd

2. Create a PHP function with flip function. The following is an example function for flipping an image horizontally or vertically:

function flipImage($sourcePath, $mode, $destinationPath) {
    $sourceImage = imagecreatefromjpeg($sourcePath);
    
    if ($mode == 'horizontal') {
        $flippedImage = imageflip($sourceImage, IMG_FLIP_HORIZONTAL);
    } elseif ($mode == 'vertical') {
        $flippedImage = imageflip($sourceImage, IMG_FLIP_VERTICAL);
    }
    
    imagejpeg($flippedImage, $destinationPath);
}

In this function, the $sourcePath parameter represents the original image path, and the $mode parameter represents the flip mode ('horizontal' represents Flip horizontally ('vertical' means vertical flip), and the $destinationPath parameter represents the output path of the flipped image.

3. Finally, call this function to flip the image. The following is an example call:

$sourcePath = 'path/to/source/image.jpg';
$destinationPath = 'path/to/destination/image.jpg';
$mode = 'horizontal';

flipImage($sourcePath, $mode, $destinationPath);

In this example, we flip the original image horizontally and save the flipped image to the target path.

Summary:
This article introduces how to use PHP to rotate and flip images. By using the GD library, we can easily perform various operations on images and achieve richer image processing functions. Please use the above example code flexibly according to the actual situation to realize the image rotation and flipping functions you need.

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