update projectionbounds to have nicer bounds and enable composing scaling transformations

Author: h-spiess

src/projective/affine.jl

@@ -75,7 +75,7 @@ end
 function getprojection(scale::ScaleFixed, bounds::Bounds{N}; randstate = nothing) where N
     # If no scaling needs to be done, return a noop transform
     (scale.sizes == length.(bounds.rs)) && return IdentityTransformation()
-    
+
     ratios = (scale.sizes .+ 1) ./ length.(bounds.rs)
     upperleft = SVector{N, Float32}(minimum.(bounds.rs)) .- 1
     P = scaleprojection(ratios)
@@ -88,7 +88,7 @@ end
 
 function projectionbounds(tfm::ScaleFixed{N}, P, bounds::Bounds{N}; randstate = nothing) where N
     bounds_ = transformbounds(bounds, P)
-    return offsetcropbounds(tfm.sizes, bounds_, ntuple(_ -> 1., N))
+    return offsetcropbounds(tfm.sizes, bounds_, ntuple(_ -> 0.5, N))
 end
 
 """

src/projective/compose.jl

@@ -54,5 +54,12 @@ function getprojection(
 end
 
 function projectionbounds(composed::ComposedProjectiveTransform, P, bounds; randstate = getrandstate(composed))
-    return transformbounds(bounds, P)
+    @assert length(composed.tfms) == length(randstate)
+    P = CoordinateTransformations.IdentityTransformation()
+    for (tfm, r) in zip(composed.tfms, randstate)
+        P_tfm = getprojection(tfm, bounds; randstate = r)
+        bounds = projectionbounds(tfm, P_tfm, bounds; randstate = r)
+        P = P_tfm ∘ P
+    end
+    return bounds
 end

test/projective/affine.jl

@@ -82,14 +82,28 @@ include("../imports.jl")
             testprojective(tfm)
 
         end
+        
         @testset ExtendedTestSet "ScaleRatio" begin
             tfm = ScaleRatio((1/2, 1/2))
             @test_nowarn apply(tfm, image)
             @test_nowarn apply(tfm, keypoints)
             timage = apply(tfm, image)
             tkeypoints = apply(tfm, keypoints)
             @test !any(isnan.(timage |> itemdata))
-            @test getbounds(timage).rs == (2:26, 2:26)
+            @test getbounds(timage).rs == (1:25, 1:25)
+            @test getbounds(timage) == getbounds(tkeypoints)
+            testprojective(tfm)
+        end
+
+        @testset ExtendedTestSet "ScaleRatioTwice" begin
+            tfm = ScaleRatio((4/5, 4/5)) |> ScaleRatio((1/2, 1/2))
+            @show getbounds(image).rs
+            @test_nowarn apply(tfm, image)
+            @test_nowarn apply(tfm, keypoints)
+            timage = apply(tfm, image)
+            tkeypoints = apply(tfm, keypoints)
+            @test !any(isnan.(timage |> itemdata))
+            @test getbounds(timage).rs == (1:20, 1:20)
             @test getbounds(timage) == getbounds(tkeypoints)
             testprojective(tfm)
         end