p1 = 676
p2 = 1735
lambda2 = 7119.6
lambda1 = 5824
a = -9.3 (slider from -600 to 600, step 0.1)
C = (16.31676437421578, 444.27808903061475)
D = (2009.056208582741, 444.27808903061475)
b = 2331.7 (slider from 500 to 3000, step 0.1)
xa: a
xb: a + b
xcurs = 1955 (slider from 0 to 2047, step 1)
d: x = xcurs
aa: (lambda2 - lambda1) / (p2 - p1)
y0: lambda1 - p1 * aa
c: y = aa * xcurs + y0
ypos: aa * xcurs + y0