Merge pull request #45 from davibarreira/arc-primitive

Ellipse primitive

src/Vizagrams.jl

@@ -14,7 +14,7 @@ using FreeTypeAbstraction
 
 using Hyperscript: Hyperscript, Style, m
 using Librsvg_jll: Librsvg_jll, rsvg_convert
-using LinearAlgebra: LinearAlgebra, UniformScaling, dot, norm, normalize, ⋅
+using LinearAlgebra: LinearAlgebra, UniformScaling, dot, norm, normalize, ⋅, Diagonal
 using MLStyle: MLStyle, @data, @match
 using Memoize: @memoize
 using NamedTupleTools: NamedTupleTools
@@ -51,6 +51,7 @@ include("primitives/circle.jl")
 include("primitives/square.jl")
 include("primitives/rectangle.jl")
 include("primitives/line.jl")
+include("primitives/ellipse.jl")
 export intersects
 include("primitives/bezier.jl")
 include("primitives/polygon.jl")
@@ -59,7 +60,7 @@ include("primitives/slice.jl")
 include("primitives/gradient.jl")
 
 include("primitives/envelopes.jl")
-export Circle, Square, Rectangle, Line, Polygon
+export Circle, Square, Rectangle, Line, Polygon, Ellipse
 export RegularPolygon, TextGeom, Bezier, QBezier, CBezier
 export QBezierPolygon, CBezierPolygon, Slice, LinearAlgebra
 

src/auxiliar/auxiliary_geometric_functions.jl

@@ -121,6 +121,16 @@ function angle_between_vectors(v1::Vector, v2::Vector)
     return angle
 end
 
+"""
+atan2pi(v::Vector)
+
+Similar to `atan`, but returns an angle between [0,2pi].
+"""
+function atan2pi(v::Vector)
+    θ = atan(v[2], v[1])
+    return θ >= 0 ? θ : θ + 2π
+end
+
 # """
 # svector2ify(v::Vector{Vector{T}}) where {T}
 

src/auxiliar/normalize.jl

@@ -10,15 +10,26 @@ function centralize_graphic(t::TMark)::TMark
 end
 
 """
-normalize_graphic(t::TMark)::TMark
+normalize_graphic(t::TMark,direction=nothing)::TMark
 
 Takes a mark tree, centralizes it and then
-scale it to 1x1 size.
+scale it to 1x1 size. The direction specifies
+whether the scaling prioritizes the :width, :height or nothing.
+If the direction is `nothing`, then the function guarantees
+that the larger (width or height) is scaled in order to give 1.
+Using `direction=:width`, we guarantee a total width is 1,
+and using `:height` we guarantee that the height is 1.
 """
-function normalize_graphic(t::TMark)::TMark
+function normalize_graphic(t::TMark, direction=nothing)::TMark
     t = centralize_graphic(t)
     bb = boundingbox(t)
     w, h = bb[2] - bb[1]
-    s = 2min(1 / w, 1 / h)
+    if isnothing(direction)
+        s = 2min(1 / w, 1 / h)
+    elseif direction == :width
+        s = 2 / w
+    elseif direction == :height
+        s = 2 / h
+    end
     return U(s) * t
 end

src/backends/svgbackend.jl

@@ -310,13 +310,41 @@ function primtosvg(geom::LinearGradient, s::S)
     )
 end
 
-function reducesvg(x::Vector{SVG}; kwargs...)
-    # reduce(⋄, x; init=m("svg"; kwargs...))
-    return reduce(
-        ⋄, x; init=m("svg"; xmlns="http://www.w3.org/2000/svg", version="1.1", kwargs...)
+"""
+primtosvg(g::Ellipse, s::Style) =
+m("ellipse", cx=p.geom.c[1], cy=p.geom.c[2], rx=p.geom.rx, ry=p.geom.ry, transform="rotate(\$(r.ang))", style=dicttostring(p.s.d))
+"""
+function primtosvg(geom::Ellipse, s::S)
+    sty, attr = split_style_attributes(s)
+    return m(
+        "ellipse";
+        cx=geom.c[1],
+        cy=geom.c[2],
+        rx=geom.rx,
+        ry=geom.ry,
+        style=dicttostring(sty),
+        transform="scale(1,-1) rotate($(rad2deg(geom.ang)) $(geom.c[1]) $(geom.c[2]))",
+        attr...,
     )
 end
 
+function reducesvg(x::Vector{SVG}; style="", kwargs...)
+    reduce(⋄, x; init=m("svg"; kwargs...))
+#     tag = m("svg"; xmlns="http://www.w3.org/2000/svg", version="1.1", kwargs...)
+#     style_tag = m(
+#         "style",
+#         """
+# .mycircle {
+#   fill: gold !important;
+#   stroke: maroon;
+#   stroke-width: 2px;
+# }
+# """,
+#     )
+#     tag = tag ⋄ style_tag
+#     return reduce(⋄, x; init=tag)
+end
+
 """
 tosvg(dprim::TDiagram; height=200, width=1000)
 

src/primitives/ellipse.jl

@@ -0,0 +1,42 @@
+struct Ellipse <: GeometricPrimitive
+    rx::Real  # Semi-major axis
+    ry::Real  # Semi-minor axis
+    c::Vector  # Center of the ellipse
+    ang::Real
+end
+
+# Constructor for Ellipse with default values
+Ellipse(; rx=2, ry=1, c=[0, 0], ang=0) = Ellipse(rx, ry, c, ang)
+
+# Covariant representation of an Ellipse (CovEllipse)
+# <rx_vec, ry_vec> = 0 (inner product is zero, both vectors are perpendicular)
+struct CovEllipse
+    _1::Vector # rx_vec
+    _2::Vector # ry_vec
+    _3::Vector # center
+end
+
+# Action of a transformation group on CovEllipse
+act(g::G, x::CovEllipse) = CovEllipse(g(x._1), g(x._2), g(x._3))
+
+# Mapping from CovEllipse to Ellipse
+ψ(p::CovEllipse) = Ellipse(norm(p._1 - p._3), norm(p._2 - p._3), p._3, atan2pi(p._1 - p._3))
+
+# Mapping from Ellipse to CovEllipse
+function ϕ(p::Ellipse)
+    return CovEllipse(
+        rotatevec([p.rx, 0], p.ang) + p.c, rotatevec([0, p.ry], p.ang) + p.c, p.c
+    )
+end
+
+# """
+#     coordinates(p::Ellipse)
+# Generate points in the ellipse.
+# """
+# function coordinates(p::Ellipse)
+#     a = p.rx
+#     b = p.ry
+#     c = p.c
+#     ang = p.ang
+#     return pts = [R(ang)([a * cos(θ), b * sin(θ)]) + c for θ in 0:(2π / 100):(2π)]
+# end

src/primitives/envelopes.jl

@@ -157,6 +157,42 @@ function envelope(t::LinearGradient, s::S, v::Vector)
     return nothing
 end
 
+function envelope(e::Ellipse, s::S, v::Vector)
+    # Normalize the direction vector
+    v_global = normalize(v)
+
+    # Compute the rotation matrix for the ellipse
+    cosθ = cos(e.ang)
+    sinθ = sin(e.ang)
+    Rot = [cosθ -sinθ; sinθ cosθ]
+
+    # Compute the covariance matrix of the ellipse
+    D = Diagonal([e.rx^2, e.ry^2])
+    Se = Rot * D * Rot'
+
+    # Compute the support function (envelope)
+    s = sqrt(v_global' * Se * v_global)
+
+    # Return the envelope value
+    return dot(e.c, v_global) + s
+end
+
+# function envelope(e::Ellipse, s::S, v::Vector)
+#     # Normalize the direction vector
+#     v = normalize(v)
+
+#     vlocal = R(-e.ang)(normalize(v))
+
+#     # Compute the envelope by scaling the vector according to the axes of the ellipse
+#     vlocal = [e.rx * vlocal[1], e.ry * vlocal[2]]
+
+#     # p = e.c + [e.rx * v[1], e.ry * v[2]]
+#     p = e.c + R(e.ang)(vlocal)
+
+#     # Return the dot product of the resulting point and the vector v
+#     return dot(p, v)
+# end
+
 envelope(p::Prim, v::Vector) = envelope(p.geom, p.s, v);
 envelope(p::GeometricPrimitive, v::Vector) = envelope(p, S(), v);
 

test/primitives/test_ellipse.jl

@@ -0,0 +1,38 @@
+import Vizagrams: CovEllipse, ϕ, ψ, coordinates
+
+# Test default constructor
+@testset "Ellipse Default Constructor" begin
+    e = Ellipse()
+    @test e.rx == 2
+    @test e.ry == 1
+    @test e.c == [0, 0]
+    @test e.ang == 0
+end
+
+# Test custom constructor
+@testset "Ellipse Custom Constructor" begin
+    e = Ellipse(rx=3, ry=4, c=[1, 2], ang=π/4)
+    @test e.rx == 3
+    @test e.ry == 4
+    @test e.c == [1, 2]
+    @test e.ang == π/4
+end
+
+# Test CovEllipse to Ellipse mapping
+@testset "CovEllipse to Ellipse Mapping" begin
+    cov_e = CovEllipse([3, 0], [0, 4], [1, 2])
+    e = ψ(cov_e)
+    @test e.rx ≈ 3
+    @test e.ry ≈ 4
+    @test e.c == [1, 2]
+    @test e.ang ≈ 0
+end
+
+# Test Ellipse to CovEllipse mapping
+@testset "Ellipse to CovEllipse Mapping" begin
+    e = Ellipse(rx=3, ry=4, c=[1, 2], ang=π/4)
+    cov_e = ϕ(e)
+    @test cov_e._1 ≈ rotatevec([3, 0], π/4) + [1, 2]
+    @test cov_e._2 ≈ rotatevec([0, 4], π/4) + [1, 2]
+    @test cov_e._3 == [1, 2]
+end

test/primitives/test_envelopes.jl

@@ -12,7 +12,8 @@ using Vizagrams
         CBezierPolygon(
             [[0, 0], [0, 1], [1, 2], [1, 1]],
             [[0, 0], [0, 1], [0.5, 1], [0.5, 2], [1, 2], [1, 1], [0.5, 1], [0.5, 0]]),
-        TextGeom(pos=[0, 0], fontsize=1, text="Hello")
+        TextGeom(pos=[0, 0], fontsize=1, text="Hello"),
+        Ellipse(ang=π / 4)
     ]
     envs = [
         [1.5, 1.0, 1.5, 1.0],
@@ -22,7 +23,9 @@ using Vizagrams
         [3.0, 1.0, 0.0, 0.0],
         [1.0, 0.5, -0.2, 0.49999999999999994],
         [1.0, 2.0, 0.0, 0.0],
-        [2.9850260416666665, 0.9563802083333333, -0.10481770833333333, 0.025390625]]
+        [2.9850260416666665, 0.9563802083333333, -0.10481770833333333, 0.025390625],
+        [1.5811388300841898, 1.5811388300841895, 1.5811388300841898, 1.5811388300841895]
+    ]
     @testset "envelope" begin
         for (i, g) in enumerate(geoms)
             for (j, v) in enumerate([[1, 0], [0, 1], [-1, 0], [0, -1]])