[Tex/LaTex] Randomly assign background colour for each frame

Question

How can a randomly picked background colour be chosen for each beamer frame?

Note:

This question is asked to round out the question Randomly assign color to background in the PDF whenever page is turned which asks for a solution which alters the colour when the pdf is displayed. On contrast the present question deals with randomly assigning colours during compilation.

Answer 1

Here is one way of doing this in ConTeXt. To set the color of a page, we need:

\definebackgrounds[page][background=color, backgroundcolor=...name...]

At each page, the setups specified in definebackgrounds are re-evaluated. So, to change the color of each page, we can simply change the value of the background color to a random color. It is easier to do so in Lua. So, here is a complete example:

\startluacode
  local random = math.random
  local format = string.format
  commands.change_color = function()
    options = { format("r=%0.3f, g=%0.3f, b=%0.3f", random(), random(), random()) }
    context.definecolor( {"randomcolor"}, options)
  end
\stopluacode

\startsetups change:color
  \ctxcommand{change_color()}
\stopsetups

\setupbackgrounds
   [page]
   [
     background=color,
     setups=change:color, 
     backgroundcolor=randomcolor,
   ]


% Just to visualize the result
\setuppapersize[A6][A2,landscape]
\setuppaper[nx=5,ny=3]
\setuparranging[XY]


\starttext

\dorecurse{15}{\null\page}

\stoptext

which gives