Problem creating a Drawable instance in compose

I need to migrate my old java code that creates a Drawable instance which is a gradient with a starting color in the upper part and a finishing color in the bottom part.

It worked perfectly in java, but after migrating the code to kotlin and compose, getDrawable function returns an empty transparent drawable:

override fun getDrawable(): Drawable {
    val sf: ShaderFactory = object : ShaderFactory() {
        override fun resize(width: Int, height: Int): Shader {
            return LinearGradient(
                startX(width), startY(height), endX(width), endY(height), intArrayOf(
                    color1, color2
                ),
                null, Shader.TileMode.MIRROR
            )
        }
    }
    val p = PaintDrawable()
    p.shape = RectShape()
    p.shaderFactory = sf
    return p
}
   
fun startX(actualWidth: Int): Float {
    when (type) {
        Type.SOLID -> return 0f
        Type.DEGREE_DOWN_UP, Type.DEGREE_UP_DOWN -> return actualWidth / 2.0f
        Type.DEGREE_LEFT_RIGHT -> return 0.0f
        Type.DEGREE_RIGHT_LEFT -> return actualWidth.toFloat()
        else -> {}
    }
    return (-1).toFloat()
}

fun startY(actualHeight: Int): Float {
    when (type) {
        Type.SOLID -> return 0f
        Type.DEGREE_DOWN_UP -> return actualHeight.toFloat()
        Type.DEGREE_LEFT_RIGHT, Type.DEGREE_RIGHT_LEFT -> return actualHeight / 2.0f
        Type.DEGREE_UP_DOWN -> return 0f
        else -> {}
    }
    return (-1).toFloat()
}

fun endX(actualWidth: Int): Float {
    when (type) {
        Type.SOLID -> return actualWidth.toFloat()
        Type.DEGREE_DOWN_UP, Type.DEGREE_UP_DOWN -> return actualWidth / 2.0f
        Type.DEGREE_LEFT_RIGHT -> return actualWidth.toFloat()
        Type.DEGREE_RIGHT_LEFT -> return 0f
        else -> {}
    }
    return (-1).toFloat()
}

fun endY(actualHeight: Int): Float {
    when (type) {
        Type.SOLID -> return actualHeight.toFloat()
        Type.DEGREE_DOWN_UP -> return 0f
        Type.DEGREE_UP_DOWN -> return actualHeight.toFloat()
        Type.DEGREE_LEFT_RIGHT, Type.DEGREE_RIGHT_LEFT -> return actualHeight / 2.0f
        else -> {}
    }
    return (-1).toFloat()
}

The type of the drawable is DEGREE_UP_DOWN

What is wrong in the code?