How to use image processing functions in PHP?

PHP provides image processing functions for editing images, including: resizing: using imagecreatefromjpeg() and imagecopyresampled() cropping: imagecrop() rotation: imagerotate() watermark: imagealphablending() and imagetext() gradient: imagecreatetruecolor( ) and imagefilledrectangle()

PHP Image Processing Functions Guide

Introduction

PHP provides a series of image processing functions for manipulating and editing images. This article will teach you how to use these functions to create and modify images from scratch.

Practical case: Adjust image size

To adjust the size of the image, you can use imagecreatefromjpeg() and imagecopyresampled() Function:

// 创建图像资源
$image = imagecreatefromjpeg('original.jpg');

// 计算新的图像尺寸
$newWidth = 500;
$newHeight = 300;

// 创建一个具有新尺寸的新图像
$newImage = imagecreatetruecolor($newWidth, $newHeight);

// 调整图片大小
imagecopyresampled($newImage, $image, 0, 0, 0, 0, $newWidth, $newHeight, imagesx($image), imagesy($image));

// 输出修改后的图像
imagejpeg($newImage, 'resized.jpg', 100);

Other image processing functions

In addition to resizing, PHP also provides other image processing functions, such as:

• Crop image: imagecrop()
• Rotate image: imagerotate()
• Create text watermark: imagealphablending() and imagetext()
• Creating a gradient: imagecreatetruecolor() and imagefilledrectangle()

Use case

Image Handling functions can be used in a variety of applications, including:

• Resizing website images
• Creating thumbnails
• Add watermark to image
• Create image to share on social media

Conclusion

PHP image processing functions provide the functionality you need to easily create and modify images. Through the practical cases and function list provided in this article, you can start using PHP to easily implement your own image processing tasks.

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