Currently when ever a mouse near a snap point, there light blue square popping up at the nearest point.
This is very hard to see.
Here are some suggestions to improve such visual feedback for accessibility reasons:
1) Thicker crosshair and selectable alternate "crosshair" symbols, e.g one with yellow highlights or an antenna beacon radiating arc lines icon.
2) At snap points, turn on multiple concentric squares or circles, each of different colors, and also allow blinking
-Innermost square or circle is smallest, next is 2 pixels or more larger, outermost (3rd) is slightly larger.
Each square or circle should have a unique color ( Red, blue, and green ).
Allow each items to blink alternately.
There are many other ways to do these improvements for 1) and 2).
Making such choice selectable would be nice.
3) Allow for white background on canvas.
Gray is the worsg contrast choices you can have.
Other existing background are not much better.
These suggestions if implemented, will help with :
a) color blindness
b) visually challenged
c) improving the depressing look and feel of overall UI and UI interactions
d) and last but not least, those who are no longer spring chickens... 


Right now the grade for UI quality is C--, on a good day.