allow manually specifying DPI

Project.toml

@@ -11,7 +11,7 @@ InteractiveUtils = "b77e0a4c-d291-57a0-90e8-8db25a27a240"
 [compat]
 FileIO = "1"
 ImageCore = "0.8.1, 0.9"
-ImageMagick_jll = "= 6.9.10"
+ImageMagick_jll = "=6.9.10, =6.9.11"
 julia = "1.3"
 
 [extras]

src/ImageMagick.jl

@@ -134,14 +134,20 @@ const ufixedtype = Dict(10=>N6f10, 12=>N4f12, 14=>N2f14, 16=>N0f16)
 
 readblob(data::Vector{UInt8}) = load_(data)
 
-function load_(file::Union{AbstractString,IO,Vector{UInt8}}, permute_horizontal=true; ImageType=Array, extraprop="", extrapropertynames=nothing, view=false)
+function load_(
+    file::Union{AbstractString,IO,Vector{UInt8}}, permute_horizontal::Bool=true;
+    ImageType=Array, extraprop="", extrapropertynames=nothing, view::Bool=false,
+    wand::MagickWand=MagickWand(), dpi::Union{Nothing,Real}=nothing,
+)
     if ImageType != Array
         error("this function now returns an Array, do not use ImageType keyword.")
     end
     if extraprop != "" || extrapropertynames != nothing
         error("keywords \"extraprop\" and \"extrapropertynames\" no longer work, use magickinfo instead")
     end
-    wand = MagickWand()
+    if dpi !== nothing
+        setresolution(wand, dpi, dpi)
+    end
     readimage(wand, file)
     resetiterator(wand)
 

src/libmagickwand.jl

@@ -450,3 +450,9 @@ function queryoption(option::AbstractString)
     p = ccall((:MagickQueryConfigureOption, libwand), Ptr{UInt8}, (Ptr{UInt8},), option)
     unsafe_string(p)
 end
+
+function setresolution(wand::MagickWand, x::Real, y::Real)
+	status = ccall((:MagickSetResolution, libwand), Cint, (Ptr{Cvoid}, Cdouble, Cdouble), wand, x, y)
+	status == 0 && error(wand)
+    nothing
+end

test/constructed_images.jl

@@ -354,4 +354,25 @@ mutable struct TestType end
         exportimagepixels!(buf2view, wand, cs, channelorder)
         @test buf2view == Ar
     end
+
+    @testset "issue #206" begin
+        img = ImageMagick.load("images/cameraman.tif")
+        @test size(img) == (512, 512)
+    end
+
+    if VERSION >= v"1.6" || Sys.which("gs") !== nothing
+        @testset "PDF" begin
+            pdf = ImageMagick.load("images/FLAT_-_What_is_Creative_Commons.pdf")
+            @test size(pdf) == (405, 720, 10)
+
+            fn = joinpath(workdir, "cc.pdf")
+            ImageMagick.save(fn, pdf)
+            @test ImageMagick.load(fn) == pdf
+
+            pdf_100dpi = ImageMagick.load("images/FLAT_-_What_is_Creative_Commons.pdf"; dpi=100)
+            @test size(pdf_100dpi) == (563, 1000, 10)
+        end
+    else
+        @warn "skipping PDF tests"
+    end
 end