add Zoom affine transformation

Author: lorenzoh

src/DataAugmentation.jl

@@ -66,6 +66,7 @@ export Item,
     Buffered,
     BufferedThreadsafe,
     OneHot,
+    Zoom,
     apply,
     Reflect,
     FlipX,

src/projective/affine.jl

@@ -63,6 +63,26 @@ function getprojection(scale::ScaleFixed{N}, bounds; randstate = nothing) where
 end
 
 
+"""
+    Zoom(scales = (1, 1.2)) <: ProjectiveTransform
+    Zoom(distribution)
+
+Zoom into an item by a factor chosen from the interval `scales`
+or `distribution`.
+"""
+struct Zoom{D<:Sampleable} <: ProjectiveTransform
+    dist::D
+end
+
+Zoom(scales::NTuple{2, T} = (1., 1.2)) where T = Zoom(Uniform(scales[1], scales[2]))
+
+getrandstate(tfm::Zoom) = rand(tfm.dist)
+
+function getprojection(tfm::Zoom, bounds::AbstractArray{<:SVector{N}}; randstate = getrandstate(tfm)) where N
+    ratio = randstate
+    return scaleprojection(ntuple(_ -> ratio, N))
+end
+
 """
     Rotate(γ)
     Rotate(γs)

src/projective/crop.jl

@@ -91,6 +91,8 @@ end
 
 
 compose(tfm::ProjectiveTransform, crop::AbstractCrop) = CroppedProjectiveTransform(tfm, crop)
+compose(tfm::ProjectiveTransform, crop::CroppedProjectiveTransform) =
+    CroppedProjectiveTransform(tfm |> crop.tfm, crop.crop)
 
 
 

src/sequence.jl

@@ -11,18 +11,20 @@ after each other.
 
 You should not use this explicitly. Instead use [`compose`](#).
 """
-struct Sequence{T<:Tuple where N} <: Transform
+struct Sequence{T<:Tuple} <: Transform
     transforms::T
 end
 
 Sequence(tfms...) = Sequence{typeof(tfms)}(tfms)
+Sequence(tfm::Transform) = tfm
 
 getrandstate(seq::Sequence) = getrandstate.(seq.transforms)
 
 
 compose(tfm1::Transform, tfm2::Transform) = Sequence(tfm1, tfm2)
 compose(seq::Sequence, tfm::Transform) = Sequence(seq.transforms..., tfm)
 compose(seq::Sequence, ::Identity) = seq
+compose(tfm::Transform, seq::Sequence) = compose(tfm, seq.transforms...)
 
 
 function apply(seq::Sequence, items::Tuple; randstate = getrandstate(seq))