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Grayscale Image

Last updated: 2022-07-28 15:13:23

    Overview

    CI uses the imageMogr2/grayscale API to set an image to be a grayscale image.

    API Sample

    1. Processing during download

    download_url?imageMogr2/grayscale/<value>
    

    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/grayscale/<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/grayscale/<value>"
    }]
    }
    

    Parameters

    Operation name: grayscale.

    Parameter Description
    download_url URL of the input image in the format of <BucketName-APPID>.cos.<Region>.myqcloud.com/<picture name>.
    For example, examplebucket-1250000000.cos.ap-shanghai.myqcloud.com/picture.jpeg
    /grayscale/<value> Whether to set an image to be a grayscale image.
    Valid values of the value field: 0 (no), 1 (yes).
    /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: Setting an image to be a grayscale image

    This example sets an image to be a grayscale image:

    http://examples-1251000004.cos.ap-shanghai.myqcloud.com/sample.jpeg?imageMogr2/grayscale/1
    

    Output:

    img

    Sample 2: Sharpening an image 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/grayscale/1
    
    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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