Plotting curve by 2 points and their 2 tangents

[kuzhylol]

The implementation is based on Bézier curve
See https://en.wikipedia.org/wiki/B%C3%A9zier_curve

The curve is being plotted by 3 arguments!
1 - a point of start of the curve (x,y);
2 - a point of the end of the curve (x,y);
3 - two tangents to 1-2 points (tan_l,tan_r);
The main idea is based on intersections of tangents on the third point.
The intersection is calculated by the solved system of the line equations.

This implementation uses fixed-point arguments for calculating trigonometric functions.
Pay attention to arguments tan_l and tan_r!
You may choose the angle(in radians) from the angle the range [0;2*PI] which is equal [0;2^16] in fixed-point.
For example, your angle is 13 degrees: 0.2269 rad -> 2367 is the argument!
See algorithm https://www.logre.eu/wiki/Trigonom%C3%A9trie_en_virgule_fixe
This move has given us a significant increase in velocity and accuracy.

The results(tangent values) have been saved in "accum" fixed-point type data for further calculations.

The next step - drawing!
The drawing is based on Bresenham's algorithm by 3 points.
See https://en.wikipedia.org/wiki/Bresenham%27s_line_algorithm