Image Processing Terminology Explanation
Overview
Before engaging in image processing, it is essential to first familiarize yourself with some basic concepts related to the process.
Basic concepts
Image service domain
It refers to the domain name used to access image services. The image service and ordinary BOS access use the same domain name. The system will provide the bucket with an official domain name directly published on the internet: <bucketname>.region.bcebos.com. Users can also add custom domain names. If the bucket has enabled CDN acceleration release, the image service will synchronously enable CDN acceleration. To enable CDN acceleration release for the bucket, please refer to [CDN Acceleration Release](BOS/Console Operation Guide/Data Publishing/Enabling CDN Official Acceleration Domain Name.md).
Note: Upgrading the Console does not impact image processing for existing domain names. The bceimg.com domain name, previously provided by the platform for trial purposes, will no longer be needed after the upgrade. However, previously activated bceimg.com domain names can still be used for six months before being reclaimed.
Processing commands
Processing commands refer to the commands included in the URL to convert and process images, formatted as "abbreviated command_parameter value." By setting parameter values in these commands, BOS generates and returns a processed image. For instance, "w_250" resizes the image width to 250 pixels.
Commands that perform a specific type of image processing can be grouped into categories. For example, commands for image scaling belong to one group, while those for image cropping belong to another.
Style
When multiple processing steps are required, image-access URLs can become complex and lengthy, making them cumbersome to manage and read. To simplify and streamline URLs or to conceal processing parameters and protect the original image, you can bundle a set of image processing commands into an image style and assign it a custom name. This allows you to apply the style name directly to achieve the desired effects without using complex command strings.
Delimiter
The delimiter is a character used in URLs to separate key fields and make them easier to identify.
Image information
Image EXIF information contains attribute details and shooting data from digital photographs, though not all images include EXIF data. EXIF information can be retrieved using specific commands.
Pipeline
It is used to connect and execute multiple independent commands. For example, the pipeline processing command format in the image processing V1.0 protocol is http://${userdomain}/${objectkey}@${commands 1}|${commands 2}, and the execution order follows the sequence specified by the pipeline from left to right.