Instead of using tint(), use a translucent fill color, by specifying a 4th (alpha) parameter to fill().  You can do the same to stroke as well, if you are using stroked ellipses.

I tried that but it only fills individual dots. And since some dots are overlaping this will not generate the same effect as blending out the whole canvas.



Though it can be used to make an alpha mask later on to be used for heatmaps.

More suggestions are appreciated.

bump.

Another option is to apply a mask after you draw the ellipses to pg.  Like so:

That does make sense. But unfortunately it does not work. :)

When changing the alpha towards 255 i sort of tint the whole image to white as seen in the image below. Compare with the previous post image where the underlying street is visible in the lower left corner. In this version to the left the alpha is about 200, the street layer is blended out and the whole background becomes white. The right image uses an alpha of 37 and the background is visible and the dots are faded just as intended.



Could it be that the white comes from the pg background? And if so how do I set it transparent?

Are there any other ways to take this on?

One method: Fix your mask so that the background areas are totally transparent (paint a black rectangle in the mask, and then gray circles where the alpha dots go).