Mask composed of multiple shapes with gradient fill in Sketch
I have a group of shapes that each have their own unique gradient fill. I would like to use the union of those shapes to create an alpha mask for an image behind it.
In other words, I want the union of the alpha mask effects on a bitmap/image.
Things I've tried:
union of the shapes, but I loose the fill information.
flattening shapes to bitmap, but it seems there is no way to mask a bitmap with a bitmap (use as mask is not selectable)?
Here is a screenshot of example shapes I'm talking about:
Let me see if I understand the scenario:
You have several shapes, each with a different gradient fill, which you want to merge into one, keeping the unique fills, and apply that as a mask over an image. In Sketch.
Two things to keep in mind:
- Sketch is not a photo editing environment. I don't know if it does alpha channel masks, but I really wouldn't want it to take on that bloat.
- Merged shapes are stylistically merged as well. You can't have separate style settings between the constituent parts.