Face masking for texture paint in UV / Image Editor There is "Face selection masking for painting" while in Texture painting in 3D View,
but I want to paint with a texture brush in the UV / Image Editor, so that the texture is not view angle dependent.

Is it possible to paint only on the area of specific faces, while in UV / Image Editor?
Not really at the moment.

Masks are not supported yet in the image editor though it is a feature that we will surely be implementing in the future.