Draw a colored shadow in Android Jetpack Compose

ColoredShadow.kt

/*
Copyright 2020 Cedric Kring.

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.
*/

import androidx.compose.ui.Modifier
import androidx.compose.ui.drawBehind
import androidx.compose.ui.graphics.Color
import androidx.compose.ui.graphics.Paint
import androidx.compose.ui.graphics.drawscope.drawIntoCanvas
import androidx.compose.ui.unit.Dp
import androidx.compose.ui.unit.dp

fun Modifier.drawColoredShadow(
    color: Color,
    alpha: Float = 0.2f,
    borderRadius: Dp = 0.dp,
    shadowRadius: Dp = 20.dp,
    offsetY: Dp = 0.dp,
    offsetX: Dp = 0.dp
) = this.drawBehind {
    val transparentColor = android.graphics.Color.toArgb(color.copy(alpha = 0.0f).value.toLong())
    val shadowColor = android.graphics.Color.toArgb(color.copy(alpha = alpha).value.toLong())
    this.drawIntoCanvas {
        val paint = Paint()
        val frameworkPaint = paint.asFrameworkPaint()
        frameworkPaint.color = transparentColor
        frameworkPaint.setShadowLayer(
            shadowRadius.toPx(),
            offsetX.toPx(),
            offsetY.toPx(),
            shadowColor
        )
        it.drawRoundRect(
            0f,
            0f,
            this.size.width,
            this.size.height,
            borderRadius.toPx(),
            borderRadius.toPx(),
            paint
        )
    }
}

Can you please suggest me how to achieve the Inner shadow.. like neumorphism design.

For those who are using lower API versions check out an improved version:

https://gist.github.com/arthurgonzaga/598267f570e38425fc52f97b30e0619d

android.graphics.Color.toArgb( requires API 26+

Amazing, thanks !

@cedrickring I use this code and it works fine in emulator, but I does not work in real devices.
I put setLayerType(View.LAYER_TYPE_SOFTWARE, null) and set android:hardwareAccelerated="false" in my manifest, but still it is not working.
Note: I have tested it in 4 different devices

Hello Cedric,
you gist is used in our code and I'd like to properly document and declare it according to FOSS guidelines.
Could you please tell me under which license you provided this sample code?
Cheers, Andy 👍

@fatemeh-afshari I can't say which API versions exactly are supported or what's necessary to make it work on your devices. I tested it on my Samsung Galaxy S8 on which it worked perfectly fine. I'd be happy to update the snippet if you find a solution for your problem.

@awBSH Hey Andy, I added a basic license on top of the file. Feel free to use and distribute this snippet :)

@cedrickring Hi Cedric, thank you very much 👍

android.graphics.Color.toArgb( requires API 26+

you can use this version
https://gist.github.com/tasjapr/ed66e6ba1d70cc1c6ff65ae38500a7b4

color.copy(alpha = 0.0f).toArgb()