Sketch Image Loader

Translations: 简体中文

Sketch is an image loading library specially designed for Compose Multiplatform and Android View. It has the following features:

• Multiple sources: Supports loading images from multiple sources such as http, file, compose resource, android asset/content/resource, etc.
• Powerful functions: Supports three-level caching, automatically cancels requests, automatically adjusts image size, automatically rotates images according to Exif Orientation, etc.
• Rich functions: Supports Animated image, SVG images, Base64 images, and video frames
• Easy to expand: Supports expansion of various aspects such as caching, decoding, transformation, transition, placeholder, etc.
• Extended functions: Practical extensions such as pausing downloads when cellular data is provided, pausing loading during list scrolling, image type badges, download progress indicators, etc.
• Modern: Completely based on Kotlin and Kotlin coroutine design

Sample App

• Android: Please go to the Releases page to download the latest version of the installation package
• Web: https://panpf.github.io/sketch/app
• Desktop: Use kdoctor to check the running environment, and follow the prompts to install the required software, and then execute the ./package_desktop.sh command in the project root directory to package. The installation package location is included in the output.
• iOS: Please refer to the Run Sample App section to compile and run it yourself

Install

Published to mavenCentral

${LAST_VERSION}: (Not included 'v')

Compose Multiplatform:

// Provides the core functions of Sketch as well as singletons and extension 
// functions that rely on singleton implementations
implementation("io.github.panpf.sketch4:sketch-compose:${LAST_VERSION}")

// Provides the ability to load network images
implementation("io.github.panpf.sketch4:sketch-http:${LAST_VERSION}")

Important

To improve the performance of compose, please copy compose_compiler_config.conf under the sketch-core module file to your project and configure it according to the Compose Stability Configuration documentation

Android View:

// Provides the core functions of Sketch as well as singletons and extension 
// functions that rely on singleton implementations
implementation("io.github.panpf.sketch4:sketch-view:${LAST_VERSION}")

// Provides the ability to load network images
implementation("io.github.panpf.sketch4:sketch-http:${LAST_VERSION}")

Optional modules:

// Use Android or Skia's built-in decoder to decode gif animations and play them
implementation("io.github.panpf.sketch4:sketch-animated-gif:${LAST_VERSION}")

// [Android only] Use the GifDrawable of the android-gif-drawable library to decode and play gif animations
implementation("io.github.panpf.sketch4:sketch-animated-gif-koral:${LAST_VERSION}")

// [Android only] Android or Skia's built-in decoder decodes heif animations and plays them
implementation("io.github.panpf.sketch4:sketch-animated-heif:${LAST_VERSION}")

// Use Android or Skia's built-in decoder to decode webp animations and play them
implementation("io.github.panpf.sketch4:sketch-animated-webp:${LAST_VERSION}")

// Support accessing compose resources through uri or placeholder, fallback, error, etc.
implementation("io.github.panpf.sketch4:sketch-compose-resources:${LAST_VERSION}")
implementation("io.github.panpf.sketch4:sketch-extensions-compose-resources:${LAST_VERSION}")

// Provides practical functions such as download progress, image type icons, 
//  pausing loading during list scrolling, and saving cellular traffic.
implementation("io.github.panpf.sketch4:sketch-extensions-compose:${LAST_VERSION}")
implementation("io.github.panpf.sketch4:sketch-extensions-view:${LAST_VERSION}")

// [Android only] Support icon loading of apk files via file path 
implementation("io.github.panpf.sketch4:sketch-extensions-apkicon:${LAST_VERSION}")

// [Android only] Support loading icons of installed apps by package name and version code
implementation("io.github.panpf.sketch4:sketch-extensions-appicon:${LAST_VERSION}")

// [JVM only] Support using HttpURLConnection to access network images
implementation("io.github.panpf.sketch4:sketch-http-hurl:${LAST_VERSION}")

// [JVM only] Support using OkHttp to access network images
implementation("io.github.panpf.sketch4:sketch-http-okhttp:${LAST_VERSION}")

// Supports using ktor version 2.x to access network images
implementation("io.github.panpf.sketch4:sketch-http-ktor2:${LAST_VERSION}")

// Supports using ktor version 3.x to access network images
implementation("io.github.panpf.sketch4:sketch-http-ktor3:${LAST_VERSION}")

// Support SVG images
implementation("io.github.panpf.sketch4:sketch-svg:${LAST_VERSION}")

// [Android only] Use Android's built-in MediaMetadataRetriever class to decode video frames
implementation("io.github.panpf.sketch4:sketch-video:${LAST_VERSION}")

// [Android only] Decoding video frames using wseemann's FFmpegMediaMetadataRetriever library
implementation("io.github.panpf.sketch4:sketch-video-ffmpeg:${LAST_VERSION}")

Tip

• sketch-compose, sketch-view Modules all depend on the singleton provided by the sketch-singleton module. If you don’t need the singleton, you can directly rely on their *-core version.
• The sketch-http module depends on sketch-http-hurl on jvm platforms and sketch-http-ktor3 on non-jvm platforms.

Register component

Sketch supports automatic discovery and registration of Fetcher and Decoder components, which are implemented through ServiceLoader on the JVM platform and through the @EagerInitialization annotation on non-JVM platforms.

All built-in modules support automatic registration. If you want to disable automatic registration, please refer to the documentation for manual registration: 《Register component》

R8 / Proguard

Sketch itself does not need to configure any obfuscation rules, but you may need to configure it for the indirectly dependent Kotlin Coroutines, OkHttp, Okio Add obfuscation configuration

Quickly Started

Compose Multiplatform:

// val imageUri = "/Users/my/Downloads/image.jpg"
// val imageUri = file:///compose_resource/composeResources/com.github.panpf.sketch.sample.resources/files/sample.png
val imageUri = "https://www.sample.com/image.jpg"

AsyncImage(
    uri = imageUri,
    contentDescription = "photo"
)

AsyncImage(
    uri = imageUri,
    state = rememberAsyncImageState(ComposableImageOptions {
        placeholder(Res.drawable.placeholder)
        error(Res.drawable.error)
        crossfade()
        // There is a lot more...
    }),
    contentDescription = "photo"
)

AsyncImage(
    rqeuest = ComposableImageRequest(imageUri) {
        placeholder(Res.drawable.placeholder)
        error(Res.drawable.error)
        crossfade()
        // There is a lot more...
    },
    contentDescription = "photo"
)

Image(
    painter = rememberAsyncImagePainter(
        request = ComposableImageRequest(imageUri) {
            placeholder(Res.drawable.placeholder)
            error(Res.drawable.error)
            crossfade()
            // There is a lot more...
        }
    ),
    contentDescription = "photo"
)

Tip

placeholder(Res.drawable.placeholder) needs to import the sketch-compose-resources module

Android View:

// val imageUri = "/sdcard/download/image.jpg"
// val imageUri = "file:///android_asset/image.jpg"
// val imageUri = "content://media/external/images/media/88484"
val imageUri = "https://www.sample.com/image.jpg"

imageView.loadImage(imageUri)

imageView.loadImage(imageUri) {
    placeholder(R.drawable.placeholder)
    error(R.drawable.error)
    crossfade()
    // There is a lot more...
}

val request = ImageRequest(context, imageUri) {
    placeholder(R.drawable.placeholder)
    error(R.drawable.error)
    crossfade()
    target(imageView)
    // There is a lot more...
}
context.sketch.enqueue(request)

Documents

Basic functions:

• Get Started
• Register component
• Compose
• Http: Load network images
• AnimatedImage: GIF、WEBP、HEIF
• Resize: Modify the image size
• Transformation: Transformation image
• Transition: Display images in cool transitions
• StateImage: Placeholder and error images
• Listener: Listen for request status and download progress
• DownloadCache: Understand download caching to avoid repeated downloads
• ResultCache: Understand result caching to avoid duplicate conversions
• MemoryCache: Understand memory caching to avoid repeated loading
• Fetcher: Learn about Fetcher and extend new URI types
• Decoder: Understand the decoding process of Sketch
• Target: Apply the load results to the target
• SVG: Decode SVG still images
• VideoFrames: Decode video frames
• ExifOrientation: Correct the image orientation
• ImageOptions: Manage image configurations in a unified manner
• RequestInterceptor: Intercept ImageRequest
• DecodeInterceptor: Intercept the decoding process
• Preload images into memory
• Download images
• Lifecycle
• Log

Featured functions:

• SketchImageView: Configure the request through XML attributes
• Improve the clarity of long images in grid lists
• Displays the download progress
• Displays the image type corner
• Pause image downloads on cellular data to save data
• The list slides to pause the loading of images
• Displays an icon for an apk file or installed app

Change log

Please review the CHANGELOG.md file

Test Platform

• Android: Emulator; Arm64; API 21-34
• Desktop: macOS; 14.6.1; JDK 17
• iOS: iphone 16 simulator; iOS 18.1
• Web: Chrome; 130

Run Sample App

Prepare the environment:

1. Android Studio: Koala+ (2024.1.1+)
2. JDK: 17+
3. Use kdoctor to check the running environment and follow the prompts to install the required software
4. Android Studio installs the Kotlin Multiplatform and Compose Multiplatform IDE Supportplugins

Run the sample app:

1. Clone the project and open it using Android Studio
2. The running configurations of each platform have been added to the .run directory. After synchronization is completed, directly select the running configuration of the corresponding platform in the running configuration drop-down box at the top of Android Studio and click Run.
3. The running configuration of the ios platform requires you to manually create it according to the template, as follows:
   1. Copy the .run/iosSample.run.template.xml file and remove the .template suffix. The .ignore file has been configured to ignore iosSample.run.xml
   2. Click Edit Configurations in the run configuration drop-down box at the top, select iosSample and then configure Execute target

About version 4.0

• The maven groupId is upgraded to io.github.panpf.sketch4, so versions 2.* and 3.* will not prompt for upgrade
• Version 4.0 is specially built for Compose Multiplatform, so there are many breaking changes in the API, please upgrade with caution
• Version 4.0 has made a lot of simplifications and is much simpler than version 3.0, please check the update log for details
• Android minimum API raised to API 21
• Kotlin version upgraded to 2.0.0

Special thanks

• coil-kt/coil: Sketch uses some code from Coil, including framework, compose and sketch-animated movie part
• koral--/android-gif-drawable: animated-koralgif
• wseemann/FFmpegMediaMetadataRetriever: video-ffmpeg
• BigBadaboom/androidsvg: svg

My Projects

The following are my other open source projects. If you are interested, you can learn about them:

• zoomimage: Library for zoom images, supported Android View, Compose and Compose Multiplatform; supported double-click zoom, One or two fingers gesture zoom, single-finger drag, inertial sliding, positioning, rotation, super-large image subsampling and other functions.
• assembly-adapter: A library on Android that provides multi-type Item implementations for various adapters. Incidentally, it also provides the most powerful divider for RecyclerView.
• sticky-item-decoration: RecyclerView sticky item implementation

License

Apache 2.0. See the LICENSE file for details.