How to save pictures without uploading in php

In Web development, image processing is an essential part. Usually, developers need to use the file upload function to save images to the server. But in some cases, we need to save the image directly to the server without uploading it. This article will introduce how to use PHP to save images directly to the server.

Generally speaking, saving pictures by uploading files is a common way. Uploading files can be achieved using the $_FILES global variable that comes with PHP. However, if we do not want to save images by uploading, we must use PHP's image processing extension library or functions to write or create image files.

PHP provides many extension libraries and functions for image processing. Commonly used extension libraries include GD and Imagick, as well as functions such as imagecreate() and imagecopy(). Next we will introduce how to use them respectively.

1. Use the GD extension library to save images

GD is an extension library for PHP. It provides some functions for using images in PHP. Images can be created, modified, and output through GD. Among them, the imagejpeg() function can be used to save images as JPEG format files, the imagepng() function can be used to save images as PNG format files, and imagegif() can be used to save images as GIF type files.

The following is a sample code for saving images through the GD extension library:

<?php //获取图片数据
$data= $img_data; //假设$img_data为图片数据
//创建图像
$img_gd=imagecreatefromstring($data);
//保存为JPEG格式文件
imagejpeg($img_gd,&#39;./img/test.jpg&#39;);
//保存为PNG格式文件
imagepng($img_gd,&#39;./img/test.png&#39;);
//保存为GIF格式文件
imagegif($img_gd,&#39;./img/test.gif&#39;);
//销毁图像
imagedestroy($img_gd);
?>

2. Use the Imagick extension library to save images

Imagick is another extension library for PHP. Compared with GD, it provides more powerful image processing capabilities. It can read, write, create, modify various image file formats, and supports some advanced image processing functions. Through Imagick, we can also realize the function of saving pictures directly to the server.

The following is a sample code for saving images through the Imagick extension library:

<?php //获取图片数据
$data= $img_data; //假设$img_data为图片数据
//创建Imagick对象
$img_ima=new Imagick();
//将数据导入Imagick对象中
$img_ima->readImageBlob($data);
//设置保存格式为JPEG
$img_ima->setImageFormat('jpeg');
//保存图片
$img_ima->writeImage('./img/test.jpg');
//销毁对象
$img_ima->destroy();
?>

3. Use the imagecreatetruecolor() and imagecopy() functions to save images

In addition to using the extension library, PHP also provides some built-in functions for creating and editing images. Among them, the imagecreatetruecolor() function is used to create a true color image and returns an image identifier, and the imagecopy() function can merge two images.

The sample code is as follows:

<?php //获取图片数据
$data= $img_data; //假设$img_data为图片数据
//根据图片数据创建图像
$img_src=imagecreatefromstring($data);
//创建真彩色图像
$img_dest=imagecreatetruecolor(100, 100);
//将$img_src图像复制到$img_dest图像中
//imagecopy($dst_im, $src_im, $dst_x, $dst_y, $src_x, $src_y, $src_w, $src_h)
imagecopy($img_dest, $img_src, 0, 0, 0, 0, 100, 100);
//保存为JPEG格式文件
imagejpeg($img_dest,&#39;./img/test.jpg&#39;);
//销毁图像
imagedestroy($img_dest);
imagedestroy($img_src);
?>

The above are three methods of directly saving images using PHP. Developers can choose different methods according to their own needs. Note that when saving pictures in this way, you need to enable file read and write permissions, otherwise the save will fail.

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