Convert image in list of coordinates in Julia-CodePudding

I have this short code img_lab = rand(Lab, 10, 10) where I just have created an image of random colored pixels. Probably this question is trivial but how do I convert the output of this (which is Matrix{Lab{Float64}} (alias for Array{Lab{Float64}, 2}) to an organized list of coordinates. For example [[0,0,0.44,0.33,0.45],[0,1, ...] , ... , [10,10,0.54,0.32,0.87]] where the first two entries are the coordinates and the last three values for RGB.

CodePudding user response：

First, please make sure that you have good reasons to do this. Converting to such a format makes it harder to use the rest of Colors functionality, could have a (potentially large) performance cost, and is usually unnecessary.

Now, assuming it's necessary, here's one way to do it:

julia> using Random; Random.seed!(42)
TaskLocalRNG()

julia> img_lab = rand(Lab, 10, 10)
10×10 Matrix{Lab{Float64}}:
 Lab(17.3575, -26.8628, -55.5385)  Lab(9.1585, 86.3359, 71.5105)     …  Lab(14.4465, 87.7468, 12.1242)
 Lab(16.6439, 11.0078, -10.1264)   Lab(54.2929, -24.2044, -55.6044)     Lab(5.5968, 79.2197, -6.69094)
 Lab(39.0663, 61.8604, 90.5844)    Lab(50.2836, -78.3482, -26.4757)     Lab(6.6672, 21.7418, -100.172)
.
.
.

julia> map(keys(img_lab)) do cindex 
         rgbval = RGB(img_lab[cindex])
         [cindex[1], cindex[2], red(rgbval), green(rgbval), blue(rgbval)]
       end
10×10 Matrix{Vector{Float64}}:
 [1.0, 1.0, 0.0, 0.223779, 0.488699]        [1.0, 2.0, 0.468242, 0.0, 0.0]       …  [1.0, 10.0, 0.513226, 0.0, 0.101153]
 [2.0, 1.0, 0.196137, 0.141577, 0.218233]   [2.0, 2.0, 0.0, 0.573977, 0.885473]     [2.0, 10.0, 0.366805, 0.0, 0.118275]
 [3.0, 1.0, 0.737804, 0.0333098, 0.0]       [3.0, 2.0, 0.0, 0.583897, 0.639801]     [3.0, 10.0, 0.0, 0.136071, 0.65593]
 [4.0, 1.0, 0.117582, 0.0803492, 0.209829]  [4.0, 2.0, 0.833069, 0.433512, 1.0]     [4.0, 10.0, 0.818553, 0.673722, 0.202751]
 [5.0, 1.0, 0.0, 0.267613, 0.416236]        [5.0, 2.0, 0.0, 1.0, 1.0]               [5.0, 10.0, 0.26368, 0.0, 0.0]
 [6.0, 1.0, 0.0, 0.703393, 0.0]             [6.0, 2.0, 0.89057, 0.980158, 1.0]   …  [6.0, 10.0, 0.491448, 0.47962, 0.891735]
 [7.0, 1.0, 0.0, 1.0, 0.819822]             [7.0, 2.0, 1.0, 0.773939, 1.0]          [7.0, 10.0, 0.0, 1.0, 1.0]
 [8.0, 1.0, 1.0, 0.707005, 0.402694]        [8.0, 2.0, 0.0, 0.820631, 1.0]          [8.0, 10.0, 0.0, 0.3219, 0.91962]
 [9.0, 1.0, 1.0, 0.830982, 0.928663]        [9.0, 2.0, 0.0, 0.279664, 0.0]          [9.0, 10.0, 0.937227, 0.650945, 0.442197]
 [10.0, 1.0, 0.291409, 0.0, 0.28529]        [10.0, 2.0, 1.0, 0.682411, 1.0]         [10.0, 10.0, 0.0, 0.475448, 0.941526]

(From my limited understanding, Lab-to-RGB conversion is a lossy one - and the number of 0.0s and 1.0s in the color values above seems to indicate that too, values outside the RGB gamut getting clamped to be within its limits.)