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Thumbnails

A component for loading and storing website thumbnails (screenshot of the website).

Usage

Setting up the dependency

Use Gradle to download the library from maven.mozilla.org (Setup repository):

implementation "org.mozilla.components:browser-thumbnails:{latest-version}"

Requesting thumbnails

To get thumbnail images from the browser, we need to request them from the EngineView. This can be done easily by using BrowserThumbnails which will then notify the BrowserStore when a thumbnail has been received:

browserThumbnails.set(
    feature = BrowserThumbnails(context, layout.engineView, browserStore),
    owner = this,
    view = layout
)

BrowserThumbnails tries to make requests as frequent as possible in order to get the most up-to-date state of the site in the images.

The various situations when we try to request a thumbnail:

During the Android lifecycle event onStart.
When the selected tab's loading state changes.
More to be added..

Storing to disk

When we receive new thumbnails, we may want to persist them to disk as these images can be quite large.

To do this, we need to add the BrowserMiddleware to receive the image from the store and put it in our storage:

val thumbnailStorage by lazy { ThumbnailStorage(applicationContext) }

val store by lazy {
    BrowserStore(middleware = listOf(
        ThumbnailsMiddleware(thumbnailStorage)
    ))
}

Loading from disk

Now that we have the thumbnails stored to disk, we can access them via the ThumbnailStorage directly:

runBlocking {
    val bitmap = thumbnailStorage.loadThumbnail(
      request = ImageLoadRequest("thumbnailId", maxPreferredImageDimen)
    )
}

A better way, is to use the ThumbnailLoader:

val thumbnailLoader = ThumbnailLoader(components.thumbnailStorage)
thumbnailLoader.loadIntoView(
    view = thumbnailView,
    request = ImageLoadRequest(id = tab.id, size = thumbnailSize)
)

License

This Source Code Form is subject to the terms of the Mozilla Public
License, v. 2.0. If a copy of the MPL was not distributed with this
file, You can obtain one at http://mozilla.org/MPL/2.0/

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