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    Adjusting Brightness

    Last updated: 2024-02-18 10:36:35
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      Feature Overview

      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
      Host: <BucketName-APPID>.cos.<Region>.myqcloud.com
      Date: <GMT Date>
      Authorization: <Auth String>

      2. Processing during upload

      PUT /<ObjectKey> HTTP/1.1
      Host: <BucketName-APPID>.cos.<Region>.myqcloud.com
      Date: GMT Date
      Authorization: Auth String
      Pic-Operations: 
      {
        "is_pic_info": 1,
        "rules": [{
            "fileid": "exampleobject",
            "rule": "imageMogr2/bright/<value>"
        }]
      }
      Note:
      Pic-Operations is a JSON string. Its parameters are as described in Persistent Image Processing.

      3. Processing in-cloud data

      POST /<ObjectKey>?image_process HTTP/1.1
      Host: <BucketName-APPID>.cos.<Region>.myqcloud.com
      Date: GMT Date
      Content-length: Size
      Authorization: Auth String
      Pic-Operations: 
      {
        "is_pic_info": 1,
        "rules": [{
            "fileid": "exampleobject",
            "rule": "imageMogr2/bright/<value>"
        }]
      }
      Note:
      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:
      http://examples-1251000004.cos.ap-shanghai.myqcloud.com/sample.jpeg?imageMogr2/bright/70
      Output image:
      
      
      

      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 (&).
      http://examples-1251000004.cos.ap-shanghai.myqcloud.com/sample.jpeg?q-sign-algorithm=<signature>&imageMogr2/bright/70
      Note:
      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.
      http://examples-1251000004.cos.ap-shanghai.myqcloud.com/sample.jpeg?q-sign-algorithm=sha1&q-ak=AKID********************&q-sign-time=1593342360;1593342720&q-key-time=1593342360;1593342720&q-header-list=&q-url-param-list=watermark%252f1%252fimage%252fahr0cdovl2v4yw1wbgvzlteyntewmdawmdqucgljc2gubxlxy2xvdwquy29tl3nodwl5aw4uanbn%252fgravity%252fsoutheast&q-signature=26a429871963375c88081ef60247c5746e834a98&watermark/1/image/aHR0cDovL2V4YW1wbGVzLTEyNTEwMDAwMDQucGljc2gubXlxY2xvdWQuY29tL3NodWl5aW4uanBn/gravity/southeast
      
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