I want to add a layer of StaticLayout when rendering a custom View. However, the draw(canvas) method of StaticLayout does not support alpha. ChatGPT suggested two solutions:

1. Use saveLayerAlpha.
2. Generate a BitmapDrawable and set the paint’s alpha when drawing.
   Intuitively, using saveLayerAlpha to create an extra layer seems better than generating a bitmap.

However, my requirement involves running an alpha animation (e.g., from 0 to 255). Using solution 1 would create an extra layer in each frame during invalidate/onDraw, while solution 2 only generates a temporary BitmapDrawable, changes the paint’s alpha, and draws it on the custom View’s layer. It seems that solution 2 generates fewer objects.

example code

    override fun onDraw(canvas: Canvas) {
        super.onDraw(canvas)
        drawOthers()
        drawStaticLayoutWithAlpha()
    }

• Solution 1 example

fun drawStaticLayoutWithAlpha(canvas: Canvas) {
    val saveCount = canvas.saveLayerAlpha(0f, 0f, width.toFloat(), height.toFloat(), alphaValue)
    staticLayout.draw(canvas)
    canvas.restoreToCount(saveCount)
}

• Solution 2 example
  use bitmapDrawable or bitmap。 The efficiency of using bitmap or BitmapDrawable is about the same, I guess.

fun drawStaticLayoutWithAlpha(canvas: Canvas) {
    drawable.alpha = alphaValue
    drawable.setBounds(0, 0, width, height)
    drawable.draw(canvas)
    // or
    val paint = Paint()
    paint.alpha = alpha
    canvas.drawBitmap(bitmap, x, y, paint)
}

My question is, please comment on the two solutions. Which one is better when there is an animation involved?