Krop: Kotlin Multiplatform Image Cropping Library

Overview

Welcome to Krop, a Kotlin Multiplatform library for cropping images, built on top of Coil. Whether you're targeting Android, iOS, web, or desktop, this library provides an easy-to-use API to customize and implement image cropping across platforms using Compose Multiplatform.

With Krop, you can seamlessly integrate image cropping functionality into your Kotlin applications, allowing users to interact with images in a native-like manner, regardless of the platform.

Why Use Krop?

• Multiplatform Compatibility: Krop works across Android, iOS, web, and desktop with the power of Kotlin Multiplatform and Compose.
• Easy Integration: Simplify image cropping by leveraging Coil, a fast and lightweight image loading library.
• Customizable: Tailor the cropping experience to fit your application's specific requirements with flexible customization options.
• Compose-based: Benefit from a modern UI framework, enabling reactive and declarative UIs across all targets.

Version Compatibility

The table below outlines the compatibility between different versions of the Krop library, Kotlin, and Coil. This ensures you can easily find the correct versions to use together in your project.

Krop Version	Kotlin Version	Coil Version
1.0.x	2.0.10+	3.0.0-alpha05+

Features

• Cross-platform Image Cropping: Use a unified API to crop images across multiple platforms. Currently support image file PNG, JPEG, WEBP
• Built on Coil: Take advantage of Coil’s efficiency and ease of use for image loading.
• Compose Multiplatform Support: Leverage the power of JetBrains Compose to create UIs that handle cropping interactions seamlessly.
• Customizability: Fine-tune the cropping area, aspect ratio, and more, to suit the needs of your app.

Getting Started

Installation

Add the following dependency to your build.gradle.kts, supporting Android, iOS, web, and desktop:

implementation("io.keeppro.krop:krop:1.0.1")

Usage

To integrate Krop into your project, Wrapping an AsyncImage with Croppable and CroppableState is all you need to get started. Here's a simple example of how you can use Krop in your Compose code:

val croppableState = rememberCroppableState(contentScale = ContentScale.Crop)

    Croppable(
        state = croppableState,
        cropHint = CropHint.Default, 
    ) {
        AsyncImage(
            model = imageRequest,
            contentDescription = null,
            imageLoader = loader,
            contentScale = ContentScale.Inside,
            onSuccess = { croppableState.prepareImage(it.result.image) },
        )
    }

Then you can call croppableState.crop() to get the cropped image. CroppableState is also responsible for setting ContentScale, beware that you have to set AsyncImage ContentScale.Inside to make things work. And set the expected image size(width, height) at Croppable. You can also customize the cropping area by setting the aspect ratio to Croppable, or enabling tap and scale of doubleTap and more.

Example Project

Check out the example project to see how you can integrate Krop into your application across platforms.

License

This project is licensed under the MIT License. See the LICENSE file for details.

Acknowledgments

• Coil for providing a fast, easy-to-use image loading library.
• Compose Multiplatform for offering a powerful UI framework that works across platforms.

Showcase

This library is already powering production applications! Check out KeepPro, a queue management app built using Krop to gain simple cropping feature.

If you're using Krop in your project, we'd love to hear from you! Feel free to open a PR and add your app to this showcase.