[Computercraft] Screen API

--(C) Corona 2013
--DO NOT STEAL THIS CODE!!!
local ver = 0.36

function version()
  return ver
end

function about()
  print("--------------------------------------------------")
  print("Screen API Version "..version().." (C) Corona 2013")
  print("--------------------------------------------------")
end

function drawButton(button,boolCenter)
  xStart=button["x1"]
  xEnd=button["x2"]
  yStart=button["y1"]
  yEnd=button["y2"]
  x=xEnd-xStart
  y=yEnd-yStart
  term.setCursorPos(xStart,yStart)
  if (button["color"] ~= nil) and (term.isColor()) then
    term.setBackgroundColor(button["color"])
  else
    term.setBackgroundColor(colors.white)
  end
  if (button["textcolor"] ~= nil) and (term.isColor()) then
    term.setTextColor(button["textcolor"])
  else
    term.setTextColor(colors.white)
  end
  for j=0,y do
    for i=0,x do
        term.write(" ")
    end
  term.setCursorPos(xStart,yStart+j)
  end
  if (button["text"] ~= nil) and (term.isColor()) then
    if boolCenter then
      textCentery=(yStart+math.floor(y/2))
      textCenterx=(math.ceil((xStart+(x/2)))-math.ceil((string.len(button["text"])/2)))
      term.setCursorPos(textCenterx,textCentery)
    else
      term.setCursorPos(xStart,yStart)
    end
    term.write(button["text"])
  end
  term.setBackgroundColor(colors.black)
  term.setTextColor(colors.white)
end

function drawBox(area)
  x1 = area["x1"]
  x2 = area["x2"]
  y1 = area["y1"]
  y2 = area["y2"]
  xSpan = x2-x1
  ySpan = y2-y1
  cornerCount = 1
  if area["color"] ~= nil and term.isColor() then
    term.setBackgroundColor(area["color"])
  else
    term.setBackgroundColor(colors.white)
  end
  term.setCursorPos(x1,y1)
  for j=1,ySpan do
    for i=0,xSpan do
      if (cornerCount == 1) or (cornerCount == ySpan) or (i == 0) or (i == xSpan) then
        term.write(" ")
      else
        local tx,ty = term.getCursorPos()
        term.setCursorPos(tx+1,ty)
      end
    end
    cornerCount = cornerCount+1
    term.setCursorPos(x1,y1+j)
  end
end

function pressed(object,x,y)
  if (object["x2"]-object["x1"]<2) or (object["y2"]-object["y1"]<2) then
    if (object["x1"]-1<=x) and (object["x2"]>=x) and (object["y1"]<=y) and (object["y2"]>=y) then
      return true
    else
      return false
    end
  elseif (object["x2"]-object["x1"]>=2) or (object["y2"]-object["y1"]>=2) then
    if (object["x1"]-1<x) and (object["x2"]>x) and (object["y1"]-1<y) and (object["y2"]-1>y) then
      return true
    else
      return false
    end
  end
end


function cls()
  term.setBackgroundColor(colors.black)
  term.clear()
  term.setCursorPos(1,1)
end

function getFocus(area)
  term.setCursorPos(area["x1"]+1,area["y1"]+1)
end