CI uses the imageMogr2 API to adjust the brightness of an image.
An image can be processed:
During download
During upload
In the cloud
Restrictions
Format: Currently, JPG, BMP, GIF, PNG, and WebP images can be processed, and HEIF images can be decoded and processed.
Size: The input image cannot be larger than 32 MB, with its width and height not exceeding 30,000 pixels respectively, and the total number of pixels not exceeding 250 million. The width and height of the output image cannot exceed 9,999 pixels respectively. For an animated input image, the total number of pixels (width * height * number of frames) cannot exceed 250 million.
Frames (for animated images): For GIF images, the number of frames cannot exceed 300.
API Sample
1. Processing during download
GET /<ObjectKey>?imageMogr2/bright/<value> HTTP/1.1
Authorization: Auth String (for more information, see Request Signature).
When this feature is used by a sub-account, relevant permissions must be granted. For more information, see Authorization Granularity Details.
Parameters
Operation name: bright.
Parameter
Description
ObjectKey
Object name, such as folder/sample.jpg.
bright/<value>
Adjusts the brightness of an image. The value must be an integer in the range of [-100, 100].
value < 0: Reduces the image brightness.
value = 0: Does not adjust the image brightness.
value > 0: Increases the image brightness.
/ignore-error/1
If this parameter is carried and the image fails to be processed because the image is too large or a parameter value exceeds the limit, the input image will be returned with no error reported.
Samples
Note:
Processing during download is used as an example here, which does not store the output image in a bucket. If you need to store the output image, see Persistent Image Processing and use the processing during upload or processing in-cloud data feature.
Sample 1: Adjusting the brightness
This example increases the brightness of an image by 70:
Sample 2: Adjusting the brightness with a signature carried
This example processes the image in the same way as in the example above, except that a signature is carried. The signature is concatenated with other processing parameters by an ampersand (&).
You can get the value of <signature> as instructed in Request Signature.
Notes
To prevent unauthorized users from accessing or downloading the input image by using a URL that does not contain any processing parameter, you can add the processing parameters to the request signature, making the processing parameters the key of the parameter with the value left empty. The following is a simple sample for your reference (it might have expired or become inaccessible). For more information, see Upload via Pre-Signed URL.
