Laggy when zooming and drawing with pen over large raster image
#### Summary:
while I import a photo and try to trace it using pen or pencil tool inkscape become very laggy and slow
it also become very laggy in zooming in and out at that time.
#### Steps to reproduce:
<!-- Describe what you did (step-by-step) so we can reproduce: -->
- open Inkscape
- import a photo
- switch to pen or pencil tool and trace over photo
- zoom in/out
#### What happened?
- lag in some way
#### What should have happened?
- no lag.
#### Version info
unspecified.
issue