mantao/Plots.jl
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generalize curves

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This commit is contained in:
Thomas Breloff 2016-02-22 10:39:03 -05:00
parent 9da4083096
commit 6b61c5900c
1 changed files with 26 additions and 20 deletions
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46
src/components.jl
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@ -249,22 +249,22 @@ end
export
P2,
P3,
points,
BezierCurve,
curve_points,
directed_curve
typealias P2 FixedSizeArrays.Vec{2,Float64}
typealias P3 FixedSizeArrays.Vec{3,Float64}
type BezierCurve{T <: FixedSizeArrays.Vec}
points::Vector{T}
control_points::Vector{T}
end
function Base.call(bc::BezierCurve, t::Real)
p = zero(P2)
n = length(bc.points)-1
n = length(bc.control_points)-1
for i in 0:n
p += bc.points[i+1] * binomial(n, i) * (1-t)^(n-i) * t^i
p += bc.control_points[i+1] * binomial(n, i) * (1-t)^(n-i) * t^i
end
p
end
@ -272,32 +272,38 @@ end
Base.mean(x::Real, y::Real) = 0.5*(x+y)
Base.mean{N,T<:Real}(ps::FixedSizeArrays.Vec{N,T}...) = sum(ps) / length(ps)
points(curve::BezierCurve, n::Integer = 50) = map(curve, linspace(0,1,n))
curve_points(curve::BezierCurve, n::Integer = 30; range = [0,1]) = map(curve, linspace(range..., n))
# build a BezierCurve which leaves point p vertically upwards and arrives point q vertically upwards.
# may create a loop if necessary
function directed_curve(p::P2, q::P2)
mn = mean(p,q)
# may create a loop if necessary. Assumes the view is [0,1]
function directed_curve(p::P2, q::P2; xview = 0:1, yview = 0:1)
mn = mean(p, q)
diff = q - p
minx, maxx = minimum(xview), maximum(xview)
miny, maxy = minimum(yview), maximum(yview)
diffpct = P2(diff[1] / (maxx - minx),
diff[2] / (maxy - miny))
# these points give the initial/final "rise"
yoffset = max(0.4, min(1.0, abs(mn[2]-p[2])))
firstoffset = P2(0, yoffset)
uppery = p + firstoffset
lowery = q - firstoffset
vertical_offset = P2(0, (maxy - miny) * max(0.03, min(abs(0.5diffpct[2]), 1.0)))
upper_control = p + vertical_offset
lower_control = q - vertical_offset
# try to figure out when to loop around vs just connecting straight
# TODO: choose loop direction based on sign of p[1]??
insideoffset = P2(0.5, 0)
inside = []
x_close_together = abs(p[1] - q[1]) <= 0.1
p_is_higher = p[2] >= q[2]
if x_close_together && p_is_higher
x_close_together = abs(diffpct[1]) <= 0.05
p_is_higher = diff[2] <= 0
inside_control_points = if x_close_together && p_is_higher
# add curve points which will create a loop
sgn = p[1] < 0 ? -1 : 1
inside = [uppery + sgn * insideoffset, lowery + sgn * insideoffset]
sgn = p[1] < 0.5 * (maxx + minx) ? -1 : 1
inside_offset = P2(0.3 * (maxx - minx), 0)
[upper_control + sgn * inside_offset, lower_control + sgn * inside_offset]
else
[]
end
BezierCurve([p, uppery, inside..., lowery, q])
BezierCurve([p, upper_control, inside_control_points..., lower_control, q])
end
end