imagery

Components and utilities for working with images in Kotlin.

Using the library

The Image model contains everything necessary to represent an image and all of its associated data. All the models are serializable with kotlinx.serialization. To create an instance of an Image, a URI is required that points to the image resource. All other fields are optional.

val image = Image(
    uri = "https://example.com/image"
)

The Image model contains useful optional properties, such as blurHash and focalPoint. A BlurHash can be used as a placeholder while the image resource is loading. A FocalPoint keeps the most important part of the image visible when the image is clipped.

A BlurHash for an image can be obtained using a BlurHashEncoder:

val encoder = BlurHashEncoder()

val blurHash = encoder.encode(
    pixelsArray,
    width,
    height,
    componentX,
    componentY,
)

When a BlurHash is obtained, it can be rendered to an image array that can be displayed while the image is loading.

val decoder = BlurHashDecoder()

val result = decoder.decode(
    blurHash,
    width,
    height,
    punch,
)

// The result.pixels array can be used to create a platform Bitmap object.
result.pixels

A FocalPoint is created by telling which coordinates in the image array are the most important.

FocalPoint(
    imageX,
    imageY,
    imageWidth,
    imageHeight
)

A FocalPoint can be used to get the area of the image that should be displayed if the view size is smaller than the image, and the scale type is set to matrix.

val resolver = FocalPointResolver()

val result = resolver.resolve(
    viewWidth,
    viewHeight,
    imageWidth,
    imageHeight,
    focalPoint,
)

// The result object contains everything needed to create a platform matrix object to scale the image appropriately.
result.scale
result.dx
result.dy

ImageCreator

An ImageCreator can be used to create instances of an Image, including all of its data, such as the Blur Hash, in a single function call.

val imageCreator = ImageCreator(blurHashEncoder, uriMimeTypeResolver)

val image = imageCreator.create(
        uri,
        width,
        height,
        pixels,
        blurHashComponentX,
        blurHashComponentY,
        focalPointX,
        focalPointY
)

Building the library

The library is provided through Repsy.io. Checkout the releases page to get the latest version.

Repository

repositories {
    maven { url = "https://repo.repsy.io/mvn/chrynan/public" }
}

Dependencies

Core:

implementation "com.chrynan.imagery:imagery-core:VERSION"

Android:

implementation "com.chrynan.imagery:imagery-android:VERSION"

Documentation

More detailed documentation is available in the [docs] folder. The entry point to the documentation can be found here.

License

Copyright 2021 chRyNaN

Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at

   http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.