Outline of line

[shaman4d]

I have the polyline. How I can to calculate points that will outstand from this line for some distance?

[Suthers]

This is a calculus problem. Calculus helps find the slope of a line for its whole domain

If you want the points to be perpendicular to the sides, you will need to know the slope of each section (you'd have to get the pixel locations of the start and ends of the sections). Any point perpendicular to a section has the equation whose slope is the opposite of the section's slope.

i.e if y=2/3x+b

THen the perpendicular line

y=-3/2x +b

You flip the slope and change the sign (2/3 to -3/2)

'b' is the y-intercept, but you can see it as where the line would cross the left side of the stage.