Android Signature Pad is an Android library for drawing smooth signatures. It uses variable width Bézier curve interpolation based on Smoother Signatures post by Square.

• Bézier implementation for a smoother line
• Variable point size based on velocity
• Customizable pen color and size
• Bitmap, SVG and Raw-data support

Latest version of the library can be found on Maven Central.

Open your build.gradle and make sure that Maven Central repository is declared into repositories section:

   repositories {
       mavenCentral()
   }

Then, include the library as dependency:

implementation 'se.warting.signature:signature-pad:<latest_version>' // jetpack Compose views

or

implementation 'se.warting.signature:signature-view:<latest_version>' // legacy android views

Please see the /app example app for a more detailed code example of how to use the library.

1. Add the SignaturePad view to the layout you want to show.

var signaturePadAdapter: SignaturePadAdapter? = null

SignaturePadView(onReady = {
    signaturePadAdapter = it
})

Button(onClick = {
    Log.d("", signaturePadAdapter?.getSignatureSvg() ?: "null")
}) {
    Text("Save")
}

2. Configure attributes.

• penMinWidth - The minimum width of the stroke (default: 3dp).
• penMaxWidth - The maximum width of the stroke (default: 7dp).
• penColor - The color of the stroke (default: Color.BLACK).
• velocityFilterWeight - Weight used to modify new velocity based on the previous velocity ( default: 0.9).
• clearOnDoubleClick - Double click to clear pad (default: false)

3. Get signature data

• getSignatureBitmap() - A signature bitmap with a default white background. You can also customize the image's coloring e.g. getSignatureBitmap(backgroundColor: Int, penColor: Int)

• getTransparentSignatureBitmap(trimBlankSpace: Boolean = false) - A signature bitmap with a transparent background. Set trimBlankSpace = true to crop the bitmap to the signature bounds, removing surrounding blank space. You can also customize the image's coloring, e.g. getTransparentSignatureBitmap(penColor: Int)

• getSignatureSvg() - A signature Scalable Vector Graphics document.