sain
2.1.6indexedCaptures and exports signatures as ImageBitmap with customizable options for electronic documents. Includes Base64 encoding utility for easy storage and transfer across platforms.
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Sain (サイン)
A Compose Multiplatform library for capturing and exporting signatures as ImageBitmap with customizable options. Perfect for electronic signatures, legal documents, and more.
Supported platforms: Android · iOS · Desktop (JVM) · Web (JS) · Web (WasmJS)
See the project's website for full documentation.
Features
- Capture signatures as
ImageBitmapon all platforms - Customizable signature color, thickness, pad color, shape, and border
- Optional guideline with configurable style, padding, and dash pattern
- Hint text when the signature pad is empty
- State management with
rememberSignatureState()for persistence - Clear and complete actions via
SignatureAction
Installation
Add the Maven Central repository if it is not already there:
repositories {
mavenCentral()
}
Multiplatform Projects
Add the dependency to your commonMain source set:
kotlin {
sourceSets {
commonMain {
dependencies {
implementation("io.github.joelkanyi:sain:<latest-version>")
}
}
}
}
Android Projects
Add the dependency to your app's build.gradle.kts:
dependencies {
implementation("io.github.joelkanyi:sain:<latest-version>")
}
Gradle Version Catalog
Add the following to your libs.versions.toml:
[versions]
sain = "<latest-version>"
[libraries]
sain = { module = "io.github.joelkanyi:sain", version.ref = "sain" }
Then add the dependency in your build.gradle.kts:
dependencies {
implementation(libs.sain)
}
Quick Start
Add the Sain composable to your project:
var imageBitmap by remember { mutableStateOf<ImageBitmap?>() }
Sain(
signatureHeight = dp,
signaturePadColor = Color.White,
signatureBorderStroke = BorderStroke(
width = .dp,
color = MaterialTheme.colorScheme.onSurface,
),
signaturePadShape = RoundedCornerShape(dp),
onComplete = { signatureBitmap ->
(signatureBitmap != ) {
imageBitmap = signatureBitmap
} {
println()
}
},
) { action ->
Row(
modifier = Modifier
.padding(top = dp)
.fillMaxWidth(),
horizontalArrangement = Arrangement.spacedBy(dp),
) {
Button(
modifier = Modifier.weight(),
onClick = {
imageBitmap =
action(SignatureAction.CLEAR)
},
) {
Text()
}
Button(
modifier = Modifier.weight(),
onClick = {
action(SignatureAction.COMPLETE)
},
) {
Text()
}
}
}
Preview
| Android | iOS | Desktop |
|---|---|---|
 |  |  |
| Web (JS) | Web (WasmJS) |
|---|---|
 |  |
License
Copyright 2023 Joel Kanyi
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:
Unless applicable law agreed to writing, software
distributed under the License distributed an BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express implied.
See the License the specific language governing permissions
limitations under the License.