dezoomify-rs

Zoomable image downloader for Google Arts & Culture, Zoomify, IIIF, and others

dezoomify-rs

Continuous Integration

dezoomify-rs is a tiled image downloader. Some webpages present high-resolution zoomable images without a way to download them. These images are often tiled: the original large image has been split into smaller individual image files called tiles. The only way to download such an image is to download all the tiles separately and then stitch them together. This process can be automated by a tiled image downloader.

The most common tiled image downloader is probably dezoomify, an online tool which is very easy to use.

The goal of this project is not to replace the traditional dezoomify. However, some images are so large that they can’t be efficiently downloaded and displayed inside a web browser. Other times, a website tries to protect its tiles by refusing access to them when certain HTTP headers are not set to the right values. dezoomify-rs is a desktop application for Windows, MacOs and linux that does not have the same limitations as the online zoomify. dezoomify-rs also lets the user choose between several image formats, whereas in dezoomify, you can only save the image as PNG.

dezoomify-rs supports several zoomable image formats, each backed by a dedicated dezoomer. The following dezoomers are currently available:

Screenshots

dezoomify-rs screenshot

Usage instructions

Download dezoomify-rs

First of all, you have to download the application.

  1. Go to the the latest release page,
  2. download the version that matches your operating system (Windows, MacOS, or Linux),
  3. Extract the binary from the compressed file.

On some operating systems, you may have to authorize the application execution before being able to launch it. See how to do in MacOS.

Supported output image formats

Dezoomify-rs supports multiple output image formats. The format to use is determined by the name of the output file. For instance, entering dezoomify-rs http://example.com/ my_image.png on the command line will create a PNG image.

Each image format encoder has a distinct set of features and limitations :

Dezoomers

Google Arts Culture

In order to download images from google arts and culture, just open dezoomify-rs, and when asked, enter the URL of a viewing page, such as https://artsandculture.google.com/asset/light-in-the-dark/ZQFouDGMVmsI2w

Zoomify

You have to give dezoomify-rs an url to the ImageProperties.xml file. You can use dezoomify-extension to find the URL of this file.

Alternatively, you can find it out manually by opening your network inspector. If the image tile URLs have the form http://example.com/path/to/TileGroup1/1-2-3.jpg, then the URL to enter is http://example.com/path/to/ImageProperties.xml.

IIIF

The IIIF dezoomer takes the URL of an info.json file as input.

You can use dezoomify-extension to find the URL of this file.

Alternatively, you can find this url in your browser’s network inspector when loading the image.

DeepZoom

The DeepZoom dezoomer takes the URL of a dzi file as input, which you can find using dezoomify-extension.

You can find this url in your browser’s network inspector when loading the image. If the image tile URLs have the form http://test.com/y/xy_files/1/2_3.jpg, then the URL to enter is http://test.com/y/xy.dzi.

Zoomify PFF

PFF is an old zoomable image file format format developed by zoomify. You can give a pff meta-information URL (one that contains requestType=1) to dezoomify-rs and it will download it.

Krpano

Krpano is a zoomable image format often used for panoramas, virtual tours, photoshperes, and other 3d zoomable images. dezoomify-rs supports downloading individual image planes from such images. You need to provide the xml meta-information file for the image.

IIPImage

IIPImage is an image web server that implements the Internet Imaging Protocol. Such images are easily recognizable by their tile URLs, which contain FIF=. You can pass an URL containing FIF= to dezoomify-rs to let it download the image.

Generic

You can use this dezoomer if you know the format of tile URLs. For instance, if you noticed that the URL of the first tile is

http://example.com/my_image/image-0-0.jpg

and the second is

http://example.com/my_image/image-1-0.jpg

then you can guess what the general format will be, and give dezoomify-rs the following:

http://example.com/my_image/image--.jpg

If the numbers have leading zeroes in the URL (such as image-01-00.jpg instead of image-1-0.jpg), then you can specify them in the url template as follows:

http://example.com/my_image/image--.jpg

Custom yaml

The custom yaml dezoomer is a powerful tool that lets you download tiled images in many different formats, including formats that are not explicitly supported by dezoomify-rs. In order to use this dezoomer, you’ll need to create a tiles.yaml file, which is a little bit technical. However, we have a a tutorial for the custom YAML dezoomer to help you. If you are having troubles understanding the tutorial or adapting it to your use-case, you should get in touch by opening a new github issue.

Command-line options

When using dezoomify-rs from the command-line

USAGE:
    dezoomify-rs [FLAGS] [OPTIONS] [--] [ARGS]

FLAGS:
        --accept-invalid-certs    Whether to accept connecting to insecure HTTPS servers
        --help                    Prints help information
    -l, --largest                 If several zoom levels are available, then select the largest one
    -V, --version                 Prints version information

OPTIONS:
        --compression <compression>
            A number between 0 and 100 expressing how much to compress the output image. For lossy output formats such
            as jpeg, this affects the quality of the resulting image. 0 means less compression, 100 means more
            compression. Currently affects only the JPEG and PNG encoders [default: 20]
        --connect-timeout <connect-timeout>
            Time after which we should give up when trying to connect to a server [default: 6s]

    -d, --dezoomer <dezoomer>                      Name of the dezoomer to use [default: auto]
    -H, --header <headers>...
            Sets an HTTP header to use on requests. This option can be repeated in order to set multiple headers. You
            can use `-H "Referer: URL"` where URL is the URL of the website's viewer page in order to let the site think
            you come from the legitimate viewer
        --logging <logging>
            Level of logging verbosity. Set it to "debug" to get all logging messages [default: warn]

    -h, --max-height <max-height>
            If several zoom levels are available, then select the one with the largest height that is inferior to max-
            height
        --max-idle-per-host <max-idle-per-host>
            Maximum number of idle connections per host allowed at the same time [default: 32]

    -w, --max-width <max-width>
            If several zoom levels are available, then select the one with the largest width that is inferior to max-
            width
    -n, --parallelism <parallelism>
            Degree of parallelism to use. At most this number of tiles will be downloaded at the same time [default: 16]

    -r, --retries <retries>
            Number of new attempts to make when a tile load fails before giving up. Setting this to 0 is useful to speed
            up the generic dezoomer, which relies on failed tile loads to detect the dimensions of the image. On the
            contrary, if a server is not reliable, set this value to a higher number [default: 1]
        --retry-delay <retry-delay>
            Amount of time to wait before retrying a request that failed [default: 2s]

        --timeout <timeout>
            Maximum time between the beginning of a request and the end of a response before the request should be
            interrupted and considered failed [default: 30s]

ARGS:
    <input-uri>    Input URL or local file name
    <outfile>      File to which the resulting image should be saved

Documentation

Batch mode

dezoomify-rs does not yet have the ability to download multiple images at once itself. However, since it is a commandline application. You can use it within a for loop in a batch script in Windows or a bash script in Linux, MacOS (or windows with wsl).

For instance, in bash, you could create a file called urls.txt containing all the urls you want to dezoomify, and then use xargs together with dezoomify-rs :

xargs -d '\n' -n 1 ./dezoomify-rs < ./urls.txt