Android实现绘制LocationMarkerView图的示例代码

Canvas(modifier = Modifier.size(0.dp)){
  drawPath(AndroidPath(markerViewPath), color = color)
  drawPath(AndroidPath(bottomOval), color = colorOval)
}

fun getPath(radius: Float): Path{
  circleModel(radius)
  val path = Path()
  p1.setYValue(p1.y + radius * 0.2f * 1.05f) //设置 p1 底部左右两个点的y值
  p1.y += radius * 0.2f * 1.05f //设置 p1 自己的y值
  path.moveTo(p1.x, p1.y)
  path.cubicTo(p1.right.x, p1.right.y, p2.bottom.x, p2.bottom.y, p2.x, p2.y)
  path.cubicTo(p2.top.x, p2.top.y, p3.right.x, p3.right.y, p3.x, p3.y)
  path.cubicTo(p3.left.x, p3.left.y, p4.top.x, p4.top.y, p4.x, p4.y)
  path.cubicTo(p4.bottom.x, p4.bottom.y, p1.left.x, p1.left.y, p1.x, p1.y)
  path.close()
  val circle = Path()
  circle.addCircle(p3.x, p3.y + radius, markerParams.circleRadius.value, Path.Direction.CCW)
  path.op(circle, Path.Op.DIFFERENCE)
  return path
}

val locationMarker = LocationMarker(markerParams)
val markerViewPath = locationMarker.getPath(markerParams.radius.value)
val bottomOval = locationMarker.getBottomOval()
val color = colorResource(id = markerParams.wrapperColor)
val colorOval = colorResource(R.color.location_bottom_shader)
​
Canvas(modifier = Modifier.size(0.dp)){
  drawPath(AndroidPath(markerViewPath), color = color)
  drawPath(AndroidPath(bottomOval), color = colorOval)
}

val paint = Paint().asFrameworkPaint().apply {
  setColor(-0x1)
  style = android.graphics.Paint.Style.FILL
  strokeWidth = 1f
  isAntiAlias = true
  typeface = Typeface.DEFAULT_BOLD
  textSize = markerParams.txtSize.toFloat()
}

val rectF = createTextRectF(locationMarker, paint, markerParams)
val baseLineY = getTextBaseY(rectF, paint)
Canvas(modifier = Modifier.size(0.dp)){
  drawIntoCanvas {
    it.nativeCanvas.drawText(markerParams.markerStr,  rectF.left, baseLineY, paint)
  }
}

fun getTextBaseY(rectF: RectF, paint: Paint): Float {
    val fontMetrics = paint.fontMetrics
    return rectF.centerY() - fontMetrics.top / 2 - fontMetrics.bottom / 2
}

  val circleRadius by rememberSaveable{ mutableStateOf(25) }
  val radius by rememberSaveable{ mutableStateOf(60) }
  var animatedFloatFraction by remember { mutableStateOf(0f) }
  val radiusDp by animateDpAsState(
    targetValue = (radius * animatedFloatFraction).dp,
    animationSpec = tween(
      durationMillis = 1000,
      delayMillis = 500,
      easing = LinearOutSlowInEasing
    )
  )
​
  val circleRadiusDp by animateDpAsState(
    targetValue = (circleRadius * animatedFloatFraction).dp,
    animationSpec = tween(
      durationMillis = 1000,
      delayMillis = 500,
      easing = LinearOutSlowInEasing
    )
  )
​
  val markerParams by remember {
    derivedStateOf { MarkerParams(radiusDp, circleRadiusDp, wrapperColor = wrapperColor) }
  }