Affinity Designer - Clip Bitmap / Pattern Fills

[Apsis0215]

Is there a way to clip or grab imported bitmaps on the fly and clip them -  At the top of this image, the bitmap isn't quite right - but in the spirit of non-destructive editing - or 'tweaking the colors' of the bitmap, I could clip the bitmap fill until it looked right... adjusting the repeating fills around it.... If we can't - makes a good feature request : )