✨ Add asc2ply.jl and tiff2ply.jl files with initial todo comments

Author: ZenanH

src/fileio/asc2ply.jl

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+#todo

src/fileio/ply.jl

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+#==========================================================================================+
+| TABLE OF CONTENTS:                                                                       |
+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
+|  - saveply                                                                               |
+|  - readply                                                                               |
++==========================================================================================#
+
+export saveply, readply
+
+"""
+    saveply(points::AbstractArray, filename::String)
+
+Description:
+---
+Saves a point cloud to a PLY file.
+
+Example:
+---
+```julia
+points = rand(3, 1000) # 3D points
+saveply(points, "pointcloud.ply")
+# or
+saveply("pointcloud", points) # add .ply extension automatically
+
+points = rand(2, 1000) # 2D points
+saveply("pointcloud.ply", points)
+```
+"""
+function saveply(points::AbstractArray, filename::String)
+    # input check
+    n, m = size(points)
+    n in [2, 3] || throw(ArgumentError("points must be a 2D array with 2 or 3 rows"))
+    if !endswith(filename, ".ply")
+        filename *= ".ply"
+    end
+    if n == 2
+        pts = vcat(points, zeros(1, m))'
+    else
+        pts = points'
+    end
+
+    cloud = trimesh.points.PointCloud(pts)
+    cloud.export(filename)
+    @info """point data saved at 
+    $(filename)
+    """
+    return nothing
+end
+
+saveply(filename::String, points::AbstractArray) = savexyz(points, filename)
+
+"""
+    readply(filename::String; xy::Bool=false)
+
+Description:
+---
+Reads a point cloud from a PLY file. If `xy` is true, it returns only the 2D points (neglect z).
+
+Example:
+---
+```julia
+pc = readply("pointcloud.ply")
+# or
+pc = readply("pointcloud.ply", xy=true) # returns only x and y
+"""
+function readply(filename::String; xy::Bool=false)
+    isfile(filename) || throw(ArgumentError("file $(filename) does not exist"))
+    pc = py2ju(Array, trimesh.load(filename).vertices.T)
+    if xy
+        return Array(pc[1:2, :])
+    else
+        return pc
+    end
+end

src/fileio/tiff2ply.jl

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+#todo