From fccebb165a75cfc2ba7dc549e0902f0beb1ab3b6 Mon Sep 17 00:00:00 2001
From: Christof Stocker <stocker.christof@gmail.com>
Date: Fri, 21 Apr 2017 18:10:42 +0200
Subject: [PATCH] clean up WarpedView API and add warpedview

---
 src/ImageTransformations.jl |  3 +-
 src/warpedview.jl           | 88 +++++++++++++++++++++++--------------
 2 files changed, 58 insertions(+), 33 deletions(-)

diff --git a/src/ImageTransformations.jl b/src/ImageTransformations.jl
index ad58264..e90b2ce 100644
--- a/src/ImageTransformations.jl
+++ b/src/ImageTransformations.jl
@@ -21,7 +21,8 @@ export
     imresize,
     center,
     warp,
-    WarpedView
+    WarpedView,
+    warpedview
 
 include("autorange.jl")
 include("resizing.jl")
diff --git a/src/warpedview.jl b/src/warpedview.jl
index 1496fc7..4b27f40 100644
--- a/src/warpedview.jl
+++ b/src/warpedview.jl
@@ -1,37 +1,45 @@
-immutable WarpedView{T,N,A<:AbstractArray,F1<:Transformation,F2<:Transformation,I} <: AbstractArray{T,N}
+_build_extrapolation(etp::AbstractExtrapolation) = etp
+
+function _build_extrapolation{T}(itp::AbstractInterpolation{T}, fill::FillType = _default_fill(T))
+    etp = extrapolate(itp, fill)
+    _build_extrapolation(etp)
+end
+
+function _build_extrapolation{T,N,D<:Union{Linear,Constant}}(parent::AbstractArray{T,N}, degree::D = Linear(), args...)
+    itp = Interpolations.BSplineInterpolation{T,N,typeof(parent),BSpline{D},OnGrid,0}(parent)
+    _build_extrapolation(itp, args...)
+end
+
+immutable WarpedView{T,N,A<:AbstractArray,F1<:Transformation,I,F2<:Transformation,E<:AbstractExtrapolation} <: AbstractArray{T,N}
     parent::A
     transform::F1
-    transform_inv::F2
     indices::I
+    inverse::F2
+    extrapolation::E
 
-    function (::Type{WarpedView{T,N,A,F1,F2,I}}){T,N,A<:AbstractArray,F1<:Transformation,F2<:Transformation,I}(
-            parent::A, tform::F1, tinv::F2, indices::I)
+    function (::Type{WarpedView{T,N,TA,F,I}}){T,N,TA<:AbstractArray,F<:Transformation,I<:Tuple}(
+            parent::TA,
+            tform::F,
+            indices::I)
         @assert eltype(parent) == T
-        new{T,N,A,F1,F2,I}(parent, tform, tinv, indices)
+        etp = _build_extrapolation(parent)
+        tinv = inv(tform)
+        new{T,N,TA,F,I,typeof(tinv),typeof(etp)}(parent, tform, indices, tinv, etp)
     end
 end
 
-function WarpedView{T,N,F<:Transformation}(inner::WarpedView{T,N}, outer_tform::F)
+function WarpedView(inner::WarpedView, outer_tform::Transformation)
     tform = compose(outer_tform, inner.transform)
-    tinv = inv(tform)
-    etp = parent(inner)
-    inds = autorange(etp, tform)
-    WarpedView{T,N,typeof(etp),typeof(tform),typeof(tinv),typeof(inds)}(etp, tform, tinv, inds)
-end
-
-function WarpedView{T,N}(parent::AbstractArray{T,N}, args...)
-    itp = Interpolations.BSplineInterpolation{T,N,typeof(parent),Interpolations.BSpline{Interpolations.Linear},OnGrid,0}(parent)
-    WarpedView(itp, args...)
+    A = parent(inner)
+    inds = autorange(A, tform)
+    WarpedView(A, tform, inds)
 end
 
-function WarpedView{T,F<:Transformation}(itp::AbstractInterpolation{T}, tform::F, fill=_default_fill(T))
-    WarpedView(extrapolate(itp, fill), tform)
-end
-
-function WarpedView{T,N,F<:Transformation}(etp::AbstractExtrapolation{T,N}, tform::F)
-    inds = autorange(etp, tform)
-    tinv = inv(tform)
-    WarpedView{T,N,typeof(etp),F,typeof(tinv),typeof(inds)}(etp, tform, tinv, inds)
+function WarpedView{T,N,F<:Transformation,I<:Tuple}(
+        A::AbstractArray{T,N},
+        tform::F,
+        inds::I = autorange(A, tform))
+    WarpedView{T,N,typeof(A),F,I}(A, tform, inds)
 end
 
 Base.parent(A::WarpedView) = A.parent
@@ -39,24 +47,40 @@ Base.parent(A::WarpedView) = A.parent
 
 @compat Compat.IndexStyle{T<:WarpedView}(::Type{T}) = IndexCartesian()
 @inline Base.getindex{T,N}(A::WarpedView{T,N}, I::Vararg{Int,N}) =
-    _getindex(A.parent, A.transform_inv(SVector(I)))
+    _getindex(A.extrapolation, A.inverse(SVector(I)))
 
 Base.size(A::WarpedView)    = OffsetArrays.errmsg(A)
 Base.size(A::WarpedView, d) = OffsetArrays.errmsg(A)
 
-# This will return the next non-standard parent
-# This way only those extrapolations/interpolations are displayed
-# that are different to the default settings
-_next_custom(A) = A
-_next_custom(A::Interpolations.FilledExtrapolation) = _next_custom(A.itp)
-_next_custom{T,N,TI,IT<:BSpline{Linear},GT<:OnGrid}(A::Interpolations.BSplineInterpolation{T,N,TI,IT,GT}) = _next_custom(A.coefs)
-
 function ShowItLikeYouBuildIt.showarg(io::IO, A::WarpedView)
     print(io, "WarpedView(")
-    showarg(io, _next_custom(parent(A)))
+    showarg(io, parent(A))
     print(io, ", ")
     print(io, A.transform)
     print(io, ')')
 end
 
 Base.summary(A::WarpedView) = summary_build(A)
+
+"""
+TODO
+"""
+@inline warpedview(A::AbstractArray, tform::Transformation, args...) =
+    WarpedView(A, tform, args...)
+
+function warpedview{T}(
+        A::AbstractArray{T},
+        tform::Transformation,
+        degree::Union{Linear,Constant},
+        fill::FillType = _default_fill(T),
+        args...)
+    warpedview(_build_extrapolation(A, degree, fill), tform, args...)
+end
+
+function warpedview(
+        A::AbstractArray,
+        tform::Transformation,
+        fill::FillType,
+        args...)
+    warpedview(_build_extrapolation(A, Linear(), fill), tform, args...)
+end