Computercraft / CC: Tweaked Drawing Tools

--[[ DrawingTools v0.2  ]]
--[[ by Siasur | Mischa ]]

local version = 0.2

local _mt = { }
_mt.__index = _mt

-- [[  HELPERS  ]]

-- Clamps a number between a min and a max value
local function --[[ Number ]] clamp(--[[ Number ]] value, --[[ Number ]] min, --[[ Number ]] max )
  if value < min then return min end
  if value > max then return max end
  return value
end

local function --[[ String ]] getPaintColor( --[[ Color ]] color )
  local shiftCount = 0
  while bit.band(0x1, color) ~= 0x1 do
    color = bit.brshift(color, 1)
    shiftCount = shiftCount +1
  end
  return string.format("%x", shiftCount)
end

local lightColorMask = 0x7e
local darkColorMask = 0x7e00

local function --[[ Color ]] resolveColor( --[[ Color ]] color , --[[ bool ]] enableColor )

  if not color then
    error("Can't resolve nil to color", 2)
  end

  if 1 > color or color > 0x8000 then
    error("Color is out of bounds", 3)
  end

  if not enableColor then
    if bit.band(lightColorMask, color) ~= 0 then return 0x100 end
    if bit.band(darkColorMask, color) ~= 0 then return 0x80 end
  end

  return color
end

-- [[ /HELPERS  ]]

-- Clears the Buffer
function --[[ void ]] _mt.clear( --[[ Canvas ]] self )
  for x = 1, self.width, 1 do
    self.buffer[x] = self.buffer[x] or { }
    for y = 1, self.height, 1 do
      self.buffer[x][y] = self.buffer[x][y] or { }
      self.buffer[x][y].background = self.bgColor
      self.buffer[x][y].foreground = self.fgColor
      self.buffer[x][y].char = " "
    end
  end
end

-- Sets a new default background color
function --[[ void ]] _mt.setBackgroundColor( --[[ Canvas ]] self, --[[ Color ]] color )
  self.bgColor = resolveColor(color, self.isColor)
end

-- Sets a new default foreground color
function --[[ void ]] _mt.setForegroundColor( --[[ Canvas ]] self, --[[ Color ]] color )
  self.fgColor = resolveColor(color, self.isColor)
end

-- Clears the text in the given area
function --[[ void ]] _mt.eraseText( --[[ Canvas ]] self, --[[ Number ]] posX, --[[ Number ]] posY, --[[ Number ]] width, --[[ Number ]] height )
  for x = clamp(posX, 1, self.width), clamp(width + posX - 1, 1, self.width), 1 do
    for y = clamp(posY, 1, self.height), clamp(height + posY - 1, 1, self.height), 1 do
      self.buffer[x][y].char = " "
    end
  end
end

-- Draws a box in the given size at the given location
function --[[ void ]] _mt.drawBox( --[[ Canvas ]] self, --[[ Number ]] posX, --[[ Number ]] posY, --[[ Number ]] width, --[[ Number ]] height, --[[ Color ]] color)
  for x = clamp(posX, 1, self.width), clamp(width + posX - 1, 1, self.width), 1 do
    for y = clamp(posY, 1, self.height), clamp(height + posY - 1, 1, self.height), 1 do
      self.buffer[x][y].background = resolveColor(color, self.isColor)
    end
  end
end

-- Writes some text starting at the specific location
-- Returns true and and empty string if successful, false and the remaining string if it was too long
function --[[ bool, String ]] _mt.write( --[[ Canvas ]] self, --[[ Number ]] posX, --[[ Number ]] posY, --[[ String ]] text, --[[ Color? ]] color )

  if 1 > posY or posY > self.height then
    error("Can't write out of bounds! (X: " .. posX .. " Y: " .. posY .. ")", 2)
    return false, text
  end

  local remaining = string.format("%s", text)
  local step = posX
  local color = color and resolveColor(color, self.isColor) or self.fgColor
  while #remaining > 0 do
    if step > self.width then
      return false, remaining
    end
    local current = remaining:sub(1,1)
    remaining = remaining:sub(2)

    if step >= 1 then
      self.buffer[step][posY].char = current
      self.buffer[step][posY].foreground = color
    end
    step = step+1
  end
  return true, ""
end

-- Renders the Canvas to the screen
function --[[ void ]] _mt.render( --[[ Canvas ]] self )
  for y = 1, self.height, 1 do
    local lineText = ""
    local lineColorFG = ""
    local lineColorBG = ""
    for x = 1, self.width, 1 do
      lineColorBG = lineColorBG .. getPaintColor(self.buffer[x][y].background)
      lineColorFG = lineColorFG .. getPaintColor(self.buffer[x][y].foreground)
      lineText = lineText .. self.buffer[x][y].char or " "
    end

    self.screen.setCursorPos(1, y)
    self.screen.blit(lineText, lineColorFG, lineColorBG)
  end
end

-- Creates a new canvas
function --[[ Canvas ]] createCanvas( --[[ display ]] display )
  local isMonitor = display.seTextScale and true or false
  local isColor = display.isColor()
  local sizeX, sizeY = display.getSize()
  display.setCursorBlink(false)

  local canvas = {
    screen = display,
    height = sizeY,
    width = sizeX,
    isColor = isColor,
    bgColor = colors.black,
    fgColor = colors.white,
    buffer = {}
  }

  _mt.clear(canvas)

  return setmetatable(canvas, _mt)
end

-- Returns the current version number
function --[[ Number ]] getVersion()
  return version
end