A complete list of PHP image uploading and cropping techniques

Comprehensive collection of PHP image uploading and cropping skills

As a commonly used Web programming language, PHP has rich skills in processing image uploading and cropping. This article will introduce some commonly used PHP image uploading and cropping techniques and provide code examples.

1. Image upload skills

1. Use HTML form to upload images

First, we need to create a form in HTML so that users can choose and upload image files. The code is as follows:

<form action="upload.php" method="POST" enctype="multipart/form-data">
    <input type="file" name="image">
    <input type="submit" value="上传">
</form>

In the above code, we use the <input type="file"> tag to create a file upload field and name it image. When a user selects an image file and submits the form, the form data will be uploaded to a PHP file named upload.php for processing.

2. Processing image upload

In the upload.php file, we can use PHP’s file upload functionmove_uploaded_file()To handle image uploads. The code is as follows:

<?php
if ($_SERVER["REQUEST_METHOD"] == "POST") {
    $target_dir = "uploads/"; // 上传文件保存目录
    $target_file = $target_dir . basename($_FILES["image"]["name"]); // 上传文件的完整路径

    if (move_uploaded_file($_FILES["image"]["tmp_name"], $target_file)) {
        echo "文件上传成功！";
    } else {
        echo "文件上传失败！";
    }
}
?>

In the above code, first obtain the saving directory of the uploaded file $target_dir, and use the basename() function to obtain the full path of the uploaded file$target_file. Then, move the temporary file to the target location through the move_uploaded_file() function. If the file is moved successfully, "File uploaded successfully!" will be output, otherwise "File upload failed!" will be output.

2. Picture cropping skills

1. Use the GD library to crop pictures

The GD library is an extension library for processing pictures in PHP. It has rich Image processing functions. We can use the functions of the GD library to achieve image cropping. The code is as follows:

<?php
$source_image = "uploads/image.jpg"; // 原始图片路径
$target_image = "uploads/cropped_image.jpg"; // 裁剪后的图片路径

// 原始图片的尺寸
$source_width = 500;
$source_height = 300;

// 裁剪后的图片尺寸
$target_width = 200;
$target_height = 200;

// 创建裁剪后的空白图片
$cropped_image = imagecreatetruecolor($target_width, $target_height);

// 加载原始图片
$source_image = imagecreatefromjpeg($source_image);

// 裁剪图片
imagecopyresampled($cropped_image, $source_image, 0, 0, 0, 0, $target_width, $target_height, $source_width, $source_height);

// 保存裁剪后的图片
imagejpeg($cropped_image, $target_image);
?>

In the above code, the path of the original image $source_image and the path of the cropped image $target_image are first specified. Then, based on the dimensions of the original image and the dimensions of the cropped image, a blank image $cropped_image is created. Next, use the imagecreatefromjpeg() function to load the original image, and use the imagecopyresampled() function to crop the image. Finally, use the imagejpeg() function to save the cropped image.

It should be noted that the image size parameters in the above code are sample values ​​and need to be adjusted according to specific needs in actual use.

Summary:

This article introduces some commonly used PHP image uploading and cropping techniques, and provides corresponding code examples. In actual development, we can use these techniques to handle image uploading and cropping according to actual needs to improve user experience and page effects. I hope the content of this article will be helpful to readers.

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