Random static fill in Designer

The custom preset could look like this:

-- Randomly generate colours for each pixel
-- Define properties
property("RandomSeed",INTEGER,12345,0,65535,1) -- Should the output be greyscale

--Create the random table
math.randomseed(RandomSeed)
local randomvalues = {}
for i = 1, width do 
    randomvalues[i] = {}
    for j = 1, height do
        randomvalues[i][j] = {}
        randomvalues[i][j]["R"] = math.random(0,255)
        randomvalues[i][j]["G"] = math.random(0,255)
        randomvalues[i][j]["B"] = math.random(0,255)
    end
end

-- Pixel function
function pixel(frame, x, y)
    a = randomvalues[x+1][y+1]["R"]
    b = randomvalues[x+1][y+1]["G"]
    c = randomvalues[x+1][y+1]["B"]
    return a,b,c
end

Oh, thank you. This looks great. I assume the math.random(0,255) is the parameter that I can limit the choices with? 

Hi AndresK, not sure I understand your comment.
On a timeline, drag the custom preset to the timeline and adjust the 'random seed' parameter to get to a preset you like. 


(changing the math.random(0,255) will limit the min/max value for respective Red,Green and Blue)

Hi AndresK, not sure I understand your comment.
On a timeline, drag the custom preset to the timeline and adjust the 'random seed' parameter to get to a preset you like. 


(changing the math.random(0,255) will limit the min/max value for respective Red,Green and Blue)

Hi, yes, sorry - this is what I meant - to limit the min and max value. 

Building off what bas gave you if you wanted to have red, green and blue Min/Max control in Properties you could do this:

-- Randomly generate colours for each pixel
-- Define properties
property("RandomSeed",INTEGER,12345,0,65535,1) -- Should the output be greyscale
property("RedMax",INTEGER,255,0,255,1)
property("RedMin",INTEGER,0,0,255,1)
property("GreenMax",INTEGER,255,0,255,1)
property("GreenMin",INTEGER,0,0,255,1)
property("BlueMax",INTEGER,255,0,255,1)
property("BlueMin",INTEGER,0,0,255,1)

--Create the random table
math.randomseed(RandomSeed)
local randomvalues = {}
for i = 1, width do 
    randomvalues[i] = {}
    for j = 1, height do
        randomvalues[i][j] = {}
        randomvalues[i][j]["R"] = math.random(RedMin,RedMax)
        randomvalues[i][j]["G"] = math.random(GreenMin,GreenMax)
        randomvalues[i][j]["B"] = math.random(BlueMin,BlueMax)
    end
end

-- Pixel function
function pixel(frame, x, y)
    a = randomvalues[x+1][y+1]["R"]
    b = randomvalues[x+1][y+1]["G"]
    c = randomvalues[x+1][y+1]["B"]
    return a,b,c
end

Which would look like this:

Great addition Lowell - hope all is well!