如何在Android中向图像添加彩虹渐变

Question

I want to add Transparent Rainbow or Spectrum Gradient to Bitmap .

In photoshop it is very easy. Now I want to do it programmatically . I have gone through a lot of research. But gradient has only one starting color and one ending . How could I add the rainbow color(multiple color) Gradient in Android.

Or is there a way to add that effect to bitmap in Android? Like given

Answer 1

for this you can use a translucent image with the desired gradient and put it on top of your image view in a FrameLayout . then capture bitmap of the view.

once you get your layout ready use this answer to capture bitmap from it

try this to convert a view (framelayout) into a bitmap:

 public Bitmap viewToBitmap(View view) { Bitmap bitmap = Bitmap.createBitmap(view.getWidth(), view.getHeight(), Bitmap.Config.ARGB_8888); Canvas canvas = new Canvas(bitmap); view.draw(canvas); return bitmap; }