use offsets=:dsp (#50)

Author: JeffFessler

docs/lit/examples/02-ellipse.jl

@@ -76,8 +76,7 @@ jim(x, y, img, "Ellipse image")
 # Hereafter we use `ImageGeoms` to simplify the indexing.
 
 M, N = (2^8, 2^8+17) # odd
-offsets = 0.5 .* iseven.((M,N)) # subtle FFT issue!
-ig = ImageGeom(dims=(M,N), deltas=(dx,dy); offsets)
+ig = ImageGeom(dims=(M,N), deltas=(dx,dy), offsets=:dsp)
 @assert axes(ig)[1] ≈ x
 oversample = 2
 img = phantom(axes(ig)..., [ob], oversample)

docs/lit/examples/03-rect.jl

@@ -76,8 +76,7 @@ jim(x, y, img, "Rect image")
 # Hereafter we use `ImageGeoms` to simplify the indexing.
 
 M, N = (2^8, 2^8+17) # odd
-offsets = 0.5 .* iseven.((M,N)) # subtle FFT issue!
-ig = ImageGeom(dims=(M,N), deltas=(dx,dy); offsets)
+ig = ImageGeom(dims=(M,N), deltas=(dx,dy), offsets=:dsp)
 @assert axes(ig)[1] ≈ x
 oversample = 2
 img = phantom(axes(ig)..., [ob], oversample)

docs/lit/examples/04-gauss.jl

@@ -76,8 +76,7 @@ jim(x, y, img, "2D Gaussian image")
 # Hereafter we use `ImageGeoms` to simplify the indexing.
 
 M, N = (2^8, 2^8+17) # odd
-offsets = 0.5 .* iseven.((M,N)) # subtle FFT issue!
-ig = ImageGeom(dims=(M,N), deltas=(dx,dy); offsets)
+ig = ImageGeom(dims=(M,N), deltas=(dx,dy), offsets=:dsp)
 @assert axes(ig)[1] ≈ x
 oversample = 2
 img = phantom(axes(ig)..., [ob], oversample)

docs/lit/examples/05-triangle.jl

@@ -80,8 +80,7 @@ jim(x, y, img, "Triangle image")
 # Hereafter we use `ImageGeoms` to simplify the indexing.
 
 M, N = (2^8, 2^8+17) # odd
-offsets = 0.5 .* iseven.((M,N)) # subtle FFT issue!
-ig = ImageGeom(dims=(M,N), deltas=(dx,dy); offsets)
+ig = ImageGeom(dims=(M,N), deltas=(dx,dy), offsets=:dsp)
 @assert axes(ig)[1] ≈ x
 oversample = 2
 img = phantom(axes(ig)..., [ob], oversample)

docs/lit/examples/32-ellipsoid.jl

@@ -78,8 +78,7 @@ We use `ImageGeoms` to simplify the indexing.
 
 deltas = (1.0mm, 1.1mm, 0.9mm)
 dims = (2^8, 2^8+2, 49) # odd
-offsets = 0.5 .* iseven.(dims) # subtle FFT issue!
-ig = ImageGeom( ; dims, deltas, offsets)
+ig = ImageGeom( ; dims, deltas, offsets=:dsp)
 oversample = 2
 img = phantom(axes(ig)..., [ob], oversample)
 p1 = jim(axes(ig), img;

docs/lit/examples/33-cuboid.jl

@@ -78,8 +78,7 @@ We use `ImageGeoms` to simplify the indexing.
 
 deltas = (1.0mm, 1.1mm, 1.2mm)
 dims = (2^8, 2^8+2, 49) # odd
-offsets = 0.5 .* iseven.(dims) # subtle FFT issue!
-ig = ImageGeom( ; dims, deltas, offsets)
+ig = ImageGeom( ; dims, deltas, offsets=:dsp)
 oversample = 3
 img = phantom(axes(ig)..., [ob], oversample)
 p1 = jim(axes(ig), img;

docs/lit/examples/34-gauss3.jl

@@ -79,8 +79,7 @@ We use `ImageGeoms` to simplify the indexing.
 
 deltas = (1.0mm, 1.1mm, 1.2mm)
 dims = (2^8, 2^8+2, 49) # odd
-offsets = 0.5 .* iseven.(dims) # subtle FFT issue!
-ig = ImageGeom( ; dims, deltas, offsets)
+ig = ImageGeom( ; dims, deltas, offsets=:dsp)
 oversample = 2
 img = phantom(axes(ig)..., [ob], oversample)
 p1 = jim(axes(ig), img;

docs/lit/examples/35-cylinder.jl

@@ -78,8 +78,7 @@ We use `ImageGeoms` to simplify the indexing.
 
 deltas = (1.0mm, 1.1mm, 0.9mm)
 dims = (2^8, 2^8+2, 49) # odd
-offsets = 0.5 .* iseven.(dims) # subtle FFT issue!
-ig = ImageGeom( ; dims, deltas, offsets)
+ig = ImageGeom( ; dims, deltas, offsets=:dsp)
 oversample = 3
 img = phantom(axes(ig)..., [ob], oversample)
 p1 = jim(axes(ig), img;

test/shape2.jl

@@ -144,8 +144,7 @@ end
 
 @testset "spectrum" begin
     (M,N) = (2^10,2^10+5) # odd
-    offsets = 0.5 .* iseven.((M,N))
-    ig = ImageGeom( dims=(M,N), deltas=(0.02m, 0.025m); offsets)
+    ig = ImageGeom( dims=(M,N), deltas=(0.02m, 0.025m), offsets=:dsp)
     ob = shape((2m, -3m), swidth, π/6, 1.0f0)
     img = @inferred phantom(axes(ig)..., [ob])
 

test/shape3.jl

@@ -163,8 +163,7 @@ end
 
 @testset "spectrum" begin
     (L,M,N) = (2^7,2^7+2,2^7+3) # odd
-    offsets = 0.5 .* iseven.((L,M,N))
-    ig = ImageGeom( dims=(L,M,N), deltas=(1.0m, 1.1m, 1.2m); offsets)
+    ig = ImageGeom( dims=(L,M,N), deltas=(1.0m, 1.1m, 1.2m), offsets=:dsp)
     width = (30m, 40m, 50m)
     ob = shape((8m, 7m, 6m), width, (π/6, 0), 5.0f0)
     oversample = 2