OpenComputers simple graphical API (on going)

--[[
  Author: MrNaru300
  GitHub: https://github.com/MrNaru300
  Description: Just a simple graphical program
]]--



local graphics = {}

graphics.gpu = component.proxy(component.list("gpu")())
assert(graphics.gpu ~= nil, "Could not find a gpu in your system")

graphics.__screen_table = {}
graphics.screen_size = {0,0}
graphics.screen_pos = {0,0}

function graphics.resize (pos, size)
  --[[
    Resize the program borders
    @pos:
      *Where the program begins
      *Default: {0,0}
    @size:
      *The size of the program
      *Default: The screen size
  ]]--

  if(pos == nil) then pos = {1,1} end
  if(size == nil) then
    size = {graphics.gpu.getResolution()}
    size[1] = size[1] - pos[1]
    size[2] = size[2] - pos[2]
   end

  checkArg(1, pos, "table")
  checkArg(2, size, "table")

  graphics.screen_pos = pos
  graphics.screen_size = size
  graphics.__screen_table = {}

  local bg = graphics.gpu.getBackground()
  local fg = graphics.gpu.getForeground()

  for y = 0,size[2] do
    graphics.__screen_table[y] = {}
    for x = 0,size[1] do
      graphics.__screen_table[y][x] = {bg=bg, fg=fg, chr=" ", chd=false}
    end
  end

end

function graphics.render()
  --[[
    Actually renders the program
  ]]--


  local gpu = graphics.gpu
  local old_pixel = {}
  local new_pixel = {}

  for y = 0,graphics.screen_size[2] do
    for x = 0,graphics.screen_size[1] do
      new_pixel = graphics.__screen_table[y][x]
      if (old_pixel.bg ~= new_pixel.bg) then gpu.setBackground(new_pixel.bg) end
      if (old_pixel.fg ~= new_pixel.fg) then gpu.setForeground(new_pixel.fg) end
      if (new_pixel.chd) then
        gpu.set(x+graphics.screen_pos[1]-1, y+graphics.screen_pos[2]-1, graphics.__screen_table[y][x].chr)
        new_pixel.chd = false
      end
      old_pixel = new_pixel
    end
  end
end



function graphics.pixel(x, y, bg, fg, chr)

  if (chr == nil) then chr = " " end

  checkArg(1, x, "number")
  checkArg(2, y, "number")
  checkArg(3, bg, "number")
  checkArg(4, fg, "number")
  checkArg(5, chr, "string")

  chr = string.sub(chr, 1, 1)

  graphics.__screen_table[y-1][x-1] = {bg=bg,fg=fg,chr=chr,chd=true}
end

function graphics.box (init, final, bg, fg, chr)

  checkArg(1, init, "table")
  checkArg(2, final, "table")

  for x = init[1],final[1] do
    for y = init[2],final[2] do
      graphics.pixel(x,y,bg,fg,chr)
    end
  end
end

function graphics.line(init, final, bg, fg, chr)
  local variation = (init[2]-final[2])/(init[1]-final[1])

  for x = init[1],final[1]-1 do
    graphics.box({x, math.floor(variation*x+init[2])}, {x, math.floor(variation*(x+1)+init[2])}, bg, fg, chr)
  end
end

return graphics