Merge branch 'master' into tln/bump-version

src/ifds.jl

@@ -390,14 +390,13 @@ function reverse_prediction!(ifd::IFD, arr::AbstractArray{T,N}) where {T, N}
  pred::Int = predictor(ifd)
  # for planar data, each "pixel" in the strip is actually a single channel
  spp::Int = isplanar(ifd) ? 1 : nsamples(ifd)
- if pred == 2
-  @debug "reversing horizontal differencing"
+ columns = istiled(ifd) ? tilecols(ifd) : ncols(ifd)
+ rows = istiled(ifd) ? tilerows(ifd) : cld(length(arr), columns * spp)
 
- columns = istiled(ifd) ? tilecols(ifd) : ncols(ifd)
- rows = istiled(ifd) ? tilerows(ifd) : cld(length(arr), columns * spp)
+ GC.@preserve arr begin
+ if pred == 2
+ @debug "reversing horizontal differencing"
 
- # horizontal differencing
- GC.@preserve arr begin
  temp::Ptr{T} = pointer(arr)
  for row in 1:rows
  start = (row - 1) * columns * spp
@@ -410,6 +409,27 @@ function reverse_prediction!(ifd::IFD, arr::AbstractArray{T,N}) where {T, N}
  end
  end
  end
+ elseif pred == 3
+ @debug "reversing float differencing"
+
+ columns = columns * spp * sizeof(T)
+
+ temp2::Ptr{UInt8} = pointer(reinterpret(UInt8, arr))
+ for row in 1:rows
+ start = (row - 1) * columns
+ for plane in 1:spp
+ prev::UInt8 = unsafe_load(temp2, start + plane)
+ for i in (spp + plane):spp:(columns - 1) + plane
+ curr = unsafe_load(temp2, start + i) + prev
+ unsafe_store!(temp2, curr, start + i)
+ prev = curr
+ end
+ end
+ vw = view(reinterpret(UInt8, arr), start+1:start+columns)
+ vw .= deplane(vw, sizeof(T))
+ end
+
+ arr .= bswap.(arr)
  end
  end
 end

test/runtests.jl

@@ -302,3 +302,9 @@ end
 
  @test xs == recoded
 end
+
+@testset "predictor == 3" begin
+ original = get_example("shapes_uncompressed.tif")
+ encoded = get_example("shapes_lzw_predictor3.tif")
+ @test TiffImages.load(original) == TiffImages.load(encoded)
+end