Convert php image to byte array

When developing using PHP, it is often necessary to convert image files into byte arrays for easy network transmission or storage in a database. This article will introduce how to use PHP to convert images into byte arrays.

1. Use the file_get_contents() function to read image files

In PHP, use the file_get_contents() function to easily read the file contents under the specified path, including binary file types, such as Pictures, audios, videos, etc. The sample code is as follows:

$file = 'path/to/image.jpg';  // 图片文件路径
$data = file_get_contents($file);  // 读取图片内容

Here, $file is the specified image file path, and $data is the binary content of the image read. Using this method to read files, you can output the $image variable directly to the browser, allowing the browser to automatically identify the image type and display it, as shown below:

header('Content-Type:image/jpeg');  // 告诉浏览器返回的是JPEG格式的图片
echo $data;  // 输出图片数据

2. Convert image data into words Section array

After the previous step, we have successfully read the binary content of the image. Next, we need to convert it into a byte array for easy use and transmission. Here, we can use the pack() function to pack() the image data into a binary string, and then use the str_split() function to split the binary string into bytes to obtain a byte array. The sample code is as follows:

$bytes = str_split(pack('H*', bin2hex($data)));

Here, the bin2hex() function converts the binary string into hexadecimal digital form, then the pack() function packs the data into a binary string form, and finally the str_split() function converts the binary string into a hexadecimal number. Split the string into each byte to get a byte array.

3. Use base64 encoding to convert the byte array into text

Using the byte array can store the image data in the database or transmit it over the network, but usually we also need to Convert to text form to facilitate use and display in certain scenarios, such as displaying images in HTML pages. Here, we can use base64 encoding to convert the byte array into text form. The sample code is as follows:

$base64 = base64_encode($data);

Here, $data is the binary content of the image read previously, and the base64_encode() function is used to convert the binary data into base64 encoded text.

4. Summary

This article introduces how to use PHP to convert image files into byte arrays. The general steps are: first use the file_get_contents() function to read the image binary data, and then use The pack() function packs the data into a binary string form, and finally uses the str_split() function to split the binary string into each byte to obtain a byte array. If you need to convert the byte array into text form, you can use base64 encoding. These operations are widely used in network transmission and database storage.

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