Initial support for FileIO

.gitignore

@@ -21,4 +21,6 @@ docs/site/
 # It records a fixed state of all packages used by the project. As such, it should not be
 # committed for packages, but should be committed for applications that require a static
 # environment.
-Manifest.toml
+Manifest.toml
+
+.vscode

Project.toml

@@ -5,8 +5,10 @@ version = "4.6.0"
 
 [deps]
 CxxWrap = "1f15a43c-97ca-5a2a-ae31-89f07a497df4"
+FileIO = "5789e2e9-d7fb-5bc7-8068-2c6fae9b9549"
 OpenCV_jll = "33b9d88c-85f9-5d73-bd91-4e2b95a9aa0b"
 
 [compat]
+FileIO = "1.16"
 CxxWrap = "0.16"
-julia = "1.10"
+julia = "1.10"

docs/Project.toml

@@ -1,3 +1,4 @@
 [deps]
 Documenter = "e30172f5-a6a5-5a46-863b-614d45cd2de4"
-OpenCV = "f878e3a2-a245-4720-8660-60795d644f2a"
+FileIO = "5789e2e9-d7fb-5bc7-8068-2c6fae9b9549"
+OpenCV = "f878e3a2-a245-4720-8660-60795d644f2a"

docs/make.jl

@@ -7,6 +7,10 @@ DocMeta.setdocmeta!(OpenCV, :DocTestSetup, :(using OpenCV); recursive=true)
 makedocs(;
     modules=[OpenCV],
     sitename="OpenCV.jl",
+    pages = [
+        "OpenCV.jl" => "index.md"
+        "Getting started with Images" => "Getting started with Images.md"
+    ]
 )
 
 deploydocs(;

docs/src/Getting started with Images.md

@@ -0,0 +1,106 @@
+# Reading and Writing of Images
+
+OpenCV provides a wide range of functions for image processing, including reading and writing images.
+
+OpenCV.jl provides 2 ways to read and write images
+1. OpenCV native api
+2. FileIO.jl api
+
+OpenCV provides `imread` and `imwrite`, while FileIO privides `load` and `save` for similar functionalities
+
+
+!!! note
+
+    FileIO api not suppport all image formats currently but it support major formats.
+    If FileIO api not works then use OpenCV native api
+
+## Reading Images
+
+```julia
+using OpenCV
+
+img_path = "/path/to/image"
+img = OpenCV.imread(img_path)
+```
+with FileIO
+```julia
+using OpenCV, FileIO
+
+img_path = "/path/to/image"
+img = load(img_path)
+```
+
+in both cases `img` has same data. Both methods accept same reading flags[^imreadflags].
+
+```julia
+using OpenCV
+
+img_path = "/path/to/image"
+flag = OpenCV.IMREAD_UNCHANGED 
+img = OpenCV.imread(img_path, flag)
+```
+with FileIO
+```julia
+using OpenCV, FileIO
+
+img_path = "/path/to/image"
+flag = OpenCV.IMREAD_UNCHANGED 
+img = load(img_path, flag)
+```
+
+## Writing Images
+```julia
+using OpenCV
+
+img = rand(UInt8, 1000, 1000) |> OpenCV.Mat
+img_path = "/path/to/image"
+OpenCV.imwrite(img_path, img)
+```
+with FileIO
+```julia
+using OpenCV, FileIO
+
+img = rand(UInt8, 1000, 1000) |> OpenCV.Mat
+img_path = "/path/to/image"
+save(img_path, img)
+```
+
+Both methods accept same writing flags[^imwriteflags].
+
+```julia
+using OpenCV
+
+img = rand(UInt8, 1000, 1000) |> OpenCV.Mat
+img_path = "/path/to/image"
+flag = Int32[OpenCV.IMWRITE_JPEG_QUALITY, 100]
+OpenCV.imwrite(img_path, img, flag)
+```
+with FileIO
+```julia
+using OpenCV, FileIO
+
+img = rand(UInt8, 1000, 1000) |> OpenCV.Mat
+img_path = "/path/to/image"
+flag = Int32[OpenCV.IMWRITE_JPEG_QUALITY, 100]
+save(img_path, img, flag)
+```
+
+## Displaying Images
+
+When working with images, it's obviously helpful to be able to look at them. If you use Julia through Pluto, VSCode, or IJulia, images should display automatically.
+
+Preview from Pluto.jl
+
+![pluto preview](assets/pluto.png)
+
+`OpenCV.imshow` method display image on Qt window.
+
+![qt preview](assets/qt.png)
+
+`Plots.jl` To-do
+
+`Makie.jl` To-do
+
+## Notes
+[^imreadflags]: https://docs.opencv.org/4.x/d8/d6a/group__imgcodecs__flags.html#ga61d9b0126a3e57d9277ac48327799c80
+[^imwriteflags]: https://docs.opencv.org/4.x/d8/d6a/group__imgcodecs__flags.html#ga292d81be8d76901bff7988d18d2b42ac

src/OpenCV.jl

@@ -1,7 +1,12 @@
 module OpenCV
 
 using OpenCV_jll
+using FileIO
+using FileIO: DataFormat, File, Stream, stream
 
 include(joinpath(OpenCV_jll.artifact_dir, "OpenCV", "src", "OpenCV.jl"))
 
+include("fileio.jl")
+include("show.jl")
+
 end

src/fileio.jl

@@ -0,0 +1,58 @@
+const _IMAGE_DATA_FORMATS = Union{
+    format"BMP",
+    format"JP2",
+    format"JPEG",
+    format"PNG",
+    format"TIFF",
+}
+
+function _get_format_extension(fmt)
+    FileIO.info(fmt)[2]
+end
+
+## Load Images
+
+function load(f::File{T}) where {T<:_IMAGE_DATA_FORMATS}
+    data = imread(f.filename)
+    return data
+end
+
+function load(f::File{T}, flags::Int) where {T<:_IMAGE_DATA_FORMATS}
+    data = imread(f.filename, flags)
+    return data
+end
+
+function load(s::Stream{T}) where {T<:_IMAGE_DATA_FORMATS}
+    data = read(stream(s))
+    img = imdecode(reshape(data, 1, 1, :))
+    return img
+end
+
+function load(s::Stream{T}, flags::Int) where {T<:_IMAGE_DATA_FORMATS}
+    data = read(stream(s))
+    img = imdecode(reshape(data, 1, 1, :), flags)
+    return img
+end
+
+## Save Images
+
+function save(f::File{T}, image::InputArray) where {T<:_IMAGE_DATA_FORMATS}
+    imwrite(f.filename, image)
+end
+
+function save(f::File{T}, image::InputArray, params::Array{Int32,1}) where {T<:_IMAGE_DATA_FORMATS}
+    imwrite(f.filename, image, params)
+end
+
+function save(s::Stream{T}, image::InputArray) where {T<:_IMAGE_DATA_FORMATS}
+    ext = _get_format_extension(T)
+    enc_img = imencode(ext, image)[2]
+    Base.write(stream(s), enc_img)
+end
+
+function save(s::Stream{T}, image::InputArray, params::Vector{Int32}) where {T<:_IMAGE_DATA_FORMATS}
+    ext = _get_format_extension(T)
+    enc_img = imencode(ext, image, params)[2]
+    Base.write(stream(s), enc_img)
+end
+

src/show.jl

@@ -0,0 +1,5 @@
+_format_stream(format, io) = Stream{format}(io)
+
+function Base.show(io::IO, ::MIME"image/png", image::Mat{T}) where {T<:dtypes}
+	save(_format_stream(DataFormat{:PNG}, io), image)
+end

test/Project.toml

@@ -1,6 +1,7 @@
 [deps]
 Artifacts = "56f22d72-fd6d-98f1-02f0-08ddc0907c33"
 Downloads = "f43a241f-c20a-4ad4-852c-f6b1247861c6"
+FileIO = "5789e2e9-d7fb-5bc7-8068-2c6fae9b9549"
 LazyArtifacts = "4af54fe1-eca0-43a8-85a7-787d91b784e3"
 OpenCV = "f878e3a2-a245-4720-8660-60795d644f2a"
 Test = "8dfed614-e22c-5e08-85e1-65c5234f0b40"

test/runtests.jl

@@ -1,6 +1,7 @@
 using Artifacts
 using LazyArtifacts
 using OpenCV
+using FileIO
 using Test
 
 if "OPENCV_TEST_DATA_PATH" in keys(ENV)
@@ -16,4 +17,5 @@ end
     include("test_imgproc.jl")
     include("test_objdetect.jl")
     include("test_dnn.jl")
+    include("test_fileio.jl")
 end

test/test_fileio.jl

@@ -0,0 +1,58 @@
+tmpdir = mktempdir()
+
+images_path = joinpath(opencv_extra_path, "testdata", "python", "images")
+images = readdir(images_path, join=true)
+
+bmp_images = filter(endswith(".bmp"), images)
+# jp2_images = filter(endswith(".jp2"), images) # Not available
+jpg_images = filter(endswith(".jpg"), images)
+png_images = filter(endswith(".png"), images)
+tiff_images = filter(endswith(".tiff"), images)
+
+@testset "BMP" begin
+    for (idx, img_path) in enumerate(bmp_images)
+        img1 = load(img_path)
+        f = joinpath(tmpdir, "img_$idx.bmp")
+        save(f, img1)
+        img2 = load(f)
+        @test img1 == img2
+    end
+end
+
+# @testset "JP2" begin
+#     img1 = rand(UInt8, 3, 1024, 1024) |> OpenCV.Mat
+#     f = joinpath(tmpdir, "img.jp2")
+#     save(f, img1)
+#     img2 = load(f)
+#     @test OpenCV.PSNR(img1, img2) > 15
+# end
+
+@testset "JPG" begin
+    for (idx, img_path) in enumerate(jpg_images)
+        img1 = load(img_path)
+        f = joinpath(tmpdir, "img_$idx.jpg")
+        save(f, img1)
+        img2 = load(f)
+        @test OpenCV.PSNR(img1, img2) > 30
+    end
+end
+
+@testset "PNG" begin
+    for (idx, img_path) in enumerate(png_images)
+        img1 = load(img_path)
+        f = joinpath(tmpdir, "img_$idx.png")
+        save(f, img1)
+        img2 = load(f)
+        @test img1 == img2
+    end
+end
+
+@testset "TIFF" begin
+    for (idx, img_path) in enumerate(tiff_images)
+        img1 = load(img_path)
+        f = joinpath(tmpdir, "img_$idx.tiff")
+        save(f, img1)
+        img2 = load(f)
+        @test img1 == img2
+    end
+end