How to read the vertical shooting angle of a photo using PHP and Exif extension

How to read the vertical shooting angle of a photo using PHP and Exif extensions

The photo shooting angle is an important piece of information that can tell us how the photo was taken. In many application scenarios, we need to read the vertical shooting angle of the photo for further processing and analysis. In this article, we will explain how to use the PHP programming language and the Exif extension to read the vertical shooting angle of a photo.

Exif is a standard format used to store digital photo information. It contains various metadata of the photo, such as shooting time, lens parameters, shooting equipment, etc. Among them, the vertical shooting angle information is also saved through Exif. Therefore, we can obtain the vertical shooting angle by parsing the Exif data of the photo.

First, we need to make sure that PHP has the Exif extension installed. You can check whether the Exif extension is installed by executing the following command in the terminal or command line:

php -m | grep exif

If exif is included in the output, it means that the Exif extension is installed. If it is not installed, you can refer to the relevant documentation to install it.

Next, we will use PHP code to read the vertical shooting angle of the photo. Assuming that the file path of the photo is photo.jpg, the vertical shooting angle can be read through the following code:

<?php

// 读取照片的垂直拍摄角度
function getVerticalAngle($filePath) {
    $exifData = exif_read_data($filePath);
    if (isset($exifData['Orientation'])) {
        $orientation = $exifData['Orientation'];
        if ($orientation == 6) {
            return -90;  // 需要逆时针旋转90度
        } elseif ($orientation == 8) {
            return 90;  // 需要顺时针旋转90度
        }
    }
    return 0;  // 默认为0度角
}

// 测试获取照片的垂直拍摄角度
$photoFilePath = 'photo.jpg';
$verticalAngle = getVerticalAngle($photoFilePath);
echo "垂直拍摄角度：{$verticalAngle}度";

In the above code, we define a getVerticalAngle Function, which receives the photo file path as a parameter and returns the vertical shooting angle of the photo. First, we use the exif_read_data function to read the Exif data of the photo. Then, we determine the shooting direction of the photo by judging the value of the Orientation field. If the shooting direction is 6, it means that it needs to be rotated 90 degrees counterclockwise; if the shooting direction is 8, it means it needs to be rotated 90 degrees clockwise. Finally, we get the vertical shooting angle of the photo by calling the getVerticalAngle function and print it out.

Before executing the above code, make sure that the script file and the photo file are in the same directory, and name the photo file photo.jpg.

Through the above steps, we can use PHP and Exif extensions to read the vertical shooting angle of the photo. This is very useful for many application scenarios, such as picture editing, image processing or adaptive display in applications.

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