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sequence color
color = image[400][300] -- Now color is #FF0000</lang>
=={{header|FSharp}}==
FSharp can accomplish this task in several ways. This version is purely functional. The bitmap data structure does not mutate. Set pixel, for example, simply transforms the input bitmap into a new bitmap with that pixel set to the input color. If you have Framework 4.5, you can use ImmutableArray to force this immutability.
'''Solution:'''
<lang fsharp>
//pure functional version ... changing a pixel color provides a new Bitmap
type Color = {red: byte; green: byte; blue: byte}
type Point = {x:uint32; y:uint32}
type Bitmap = {color: Color array; maxX: uint32; maxY: uint32}
let colorBlack = {red = (byte) 0; green = (byte) 0; blue = (byte) 0}
let emptyBitmap = {color = Array.empty; maxX = (uint32) 0; maxY = (uint32) 0}
let bitmap (width: uint32) (height: uint32) =
match width, height with
| 0u,0u | 0u,_ | _, 0u -> emptyBitmap
| _,_ -> {color = Array.create ((int) (width * height)) colorBlack;
maxX = width;
maxY = height}
let getPixel point bitmap =
match bitmap.color with
| c when c |> Array.isEmpty -> None
| c when (uint32) c.Length <= (point.y * bitmap.maxY + point.x) -> None
| c -> Some c.[(int) (point.y * bitmap.maxY + point.x)]
let setPixel point color bitmap =
{bitmap with color = bitmap.color |> Array.mapi (function
| i when i = (int) (point.y * bitmap.maxY + point.x) ->
(fun _ -> color)
| _ -> id)}
let fill color bitmap = {bitmap with color = bitmap.color |> Array.map (fun _ ->color)}
</lang>
'''Tests:'''
<lang fsharp>
//setups
//==check pixel for color function
let check bitmap color (x,y) =
match (getPixel {x=x;y=y} bitmap) with
| Some(v) -> v = color
| _ -> false
let allPixels i j = [for x in [0u..(i-1u)] do for y in [0u..(j-1u)] -> (x,y)]
//create new empty bitmap
let myBitmap = bitmap 0u 0u
printfn "Is empty: %b" (myBitmap = emptyBitmap)
let myBitmap2 = bitmap 1u 0u
printfn "Is empty: %b" (myBitmap2 = emptyBitmap)
let myBitmap3 = bitmap 0u 1u
printfn "Is empty: %b" (myBitmap3 = emptyBitmap)
//create normal bitmap
let myBitmap4 = bitmap 14u 14u
printfn "Is not empty: %b" (not (myBitmap4 = emptyBitmap))
//just check one color
printfn "Is 1,1 black: %b" (check myBitmap4 colorBlack (1u,1u))
//check out of range color
printfn "Is 100,100 nothing: %b" (not(check myBitmap4 colorBlack (100u,100u)))
//make sure all pixels are black
printfn "Is all black: %b" ((allPixels 14u 14u) |> List.forall (check myBitmap4 colorBlack))
//fill bitmap color
let colorWhite = {red = (byte) 255; green = (byte) 255; blue = (byte) 255}
let myBitmap5 = myBitmap4 |> fill colorWhite
printfn "Is all white: %b" ((allPixels 14u 14u) |> List.forall (check myBitmap5 colorWhite))
//change just one pixel
let myBitmap6 = myBitmap5 |> setPixel {x=5u;y=10u} colorBlack
printfn "Is 5,10 black: %b" (check myBitmap4 colorBlack (5u,10u))
</lang>
{{out}}Is empty: true
Is empty: true
Is empty: true
Is not empty: true
Is 1,1 black: true
Is 100,100 nothing: true
Is all black: true
Is all white: true
Is 5,10 black: true
'''Usage:'''
<lang fsharp>
bitmap 14u 14u
|> fill {red = (byte) 200; green = (byte) 0; blue = (byte) 10}
|> setPixel {x=5u;y=10u} {red = (byte) 0; green = (byte) 0; blue = (byte) 0}
|> getPixel {x=5u;y=10u}
|> printfn "%A"
</lang>
{{out}}
Some {red = 0uy;
green = 0uy;
blue = 0uy;}
=={{header|FBSL}}==
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