@startuml

actor User
participant Client
participant Bing
participant ImageDownloader
participant BaseImage
participant PixelImage
database Web

User -> Client : Execute command
activate Client
create Bing
Client -> Bing : << new >>
Client -> Bing : Request to search images
activate Bing
Bing -> Web : Request to search images
activate Web
Web -> Web : Search images
Web -> Bing : List of image urls
deactivate Web
Bing -> Client : List of image urls
deactivate Bing

create ImageDownloader
Client -> ImageDownloader : << new >>
Client -> ImageDownloader : Request to download images
activate ImageDownloader
ImageDownloader -> Web : Request images
activate Web
Web -> ImageDownloader : Download images
deactivate Web
ImageDownloader -> ImageDownloader : Save downloaded images
ImageDownloader -> Client: List of downloaded image paths
deactivate ImageDownloader

create BaseImage
Client -> BaseImage : << new >>
BaseImage -> BaseImage : Preprocess

create PixelImage
Client -> PixelImage : << new >>

Client -> BaseImage : Request to dispatch pixel images
activate BaseImage
BaseImage -> PixelImage : Request characteristic color
activate PixelImage
PixelImage -> PixelImage : Calculate characteristic color
PixelImage -> BaseImage : Characteristic color
deactivate PixelImage
BaseImage -> BaseImage : Pick up the "nearest" image of the pixel
BaseImage -> Client : Map of dispatched images
deactivate BaseImage

Client -> PixelImage : Request to resize to pixel size
activate PixelImage
PixelImage -> PixelImage : Resize to pixel size
PixelImage -> Client : Done
deactivate PixelImage

Client->PixelImage : Request to compose mosaic image
activate PixelImage
PixelImage->PixelImage : Compose mosaic image
PixelImage->Client : Done
deactivate PixelImage

Client->User : Done
deactivate Client

@enduml