Generate thumbnails of a file message

When sending an image file, you can determine whether to create thumbnails of the image to fetch and render into your UI. You can specify up to three different sizes for thumbnail images.

Note: Supported file types are image/* and video/*. The Chat SDK doesn't support creating thumbnails when sending a file message via URL.

The sendFileMessage(params:progressHandler:completionHandler:) method requires passing a FileMessageCreateParams object as an argument to a parameter. It contains an array of ThumbnailSize objects which specify the maximum values of width and height of each thumbnail image with make(maxSize:) or make(maxWidth:maxHeight:) constructors. The completionHandler: callback subsequently returns the array of ThumbnailSize objects that each contain the URL of the generated thumbnail image file.

A thumbnail image is generated to fit within the bounds of the provided maxWidth and maxHeight. If the size of the original image is smaller than the specified dimensions, the original image will have the width and height of the specified dimensions. The URL of the thumbnail returns the location of the generated thumbnail file within the Sendbird server.

var thumbnailSizes = [ThumbnailSize]()

// Create and add a ThumbnailSize object.
// 3 thumbnail images are allowed.
thumbnailSizes.append(ThumbnailSize.make(maxSize: CGSize(width: 100.0, height: 100.0)))
thumbnailSizes.append(ThumbnailSize.make(maxWidth: 200.0, maxHeight: 200.0))

let params = FileMessageCreateParams(file: FILE)
params.fileName = FILE_NAME
params.fileSize = FILE_SIZE
params.mimeType = MIME_TYPE
params.thumbnailSizes = thumbnailSizes  // Set a ThumbnailSize object to a FileMessageCreateParams object.

channel.sendFileMessage(params: params, progressHandler: nil) { fileMessage, error in
    guard error == nil else {
        // Handle error.
        return
    }

    let first = fileMessage?.thumbnails?[0]
    let second = fileMessage?.thumbnails?[1]

    let maxSizeFirst = first?.maxSize   // 100
    let maxSizeSecond = second?.maxSize // 200

    let urlFirst = first?.url
    let urlSecond = second?.url
}