Surface API 1.0

-- Surface API version 1.0 by CrazedProgrammer
-- You may use this in your ComputerCraft programs and modify it without asking.
-- However, you may not publish this API under your name without asking me.
-- If you have any suggestions, bug reports or questions then please send an email to:
-- crazedprogrammer@gmail.com

function create(width, height, char, backcolor, textcolor)
  local surf = { }
  surf.width = width
  surf.height = height
  surf.overwrite = false
  surf.buffer = { }
  surf.save = save
  surf.drawToDisplay = drawToDisplay
  surf.clear = clear
  surf.drawPixel = drawPixel
  surf.getPixel = getPixel
  surf.drawText = drawText
  surf.drawLine = drawLine
  surf.drawRect = drawRect
  surf.fillRect = fillRect
  surf.drawSurface = drawSurface
  surf.drawSurfacePart = drawSurfacePart
  surf.drawSurfaceScaled = drawSurfaceScaled
  for i=1,width*height,1 do
    surf.buffer[(i - 1) * 3 + 1] = char
    surf.buffer[(i - 1) * 3 + 2] = backcolor
    surf.buffer[(i - 1) * 3 + 3] = textcolor
  end
  return surf
end

function load(path)
  local lines = { }
  local f = fs.open(path, "r")
  local line = f.readLine()
  while line do
    table.insert(lines, line)
    line = f.readLine()
  end
  f.close()
  local height = #lines
  if lines[1]:byte(1) == 30 then
    local width = 0
    local i = 1
    while i <= #lines[1] do
      local char = lines[1]:byte(i)
      if char == 30 or char == 31 then
        i = i + 1
      else
        width = width + 1
      end
      i = i + 1
    end
    local surf = surface.create(width, height)
    local backcolor = nil
    local testcolor = nil
    for j=1,height,1 do
      local i = 1
      local px = 1
      while i <= #lines[j] do
        local char = lines[j]:byte(i)
        if char == 30 then
          i = i + 1
          char = lines[j]:byte(i)
          local color = tonumber(lines[j]:sub(i, i), 16)
          if color then
            backcolor = 2^color
          else
            backcolor = nil
          end
        elseif char == 31 then
          i = i + 1
          char = lines[j]:byte(i)
          local color = tonumber(lines[j]:sub(i, i), 16)
          if color then
            textcolor = 2^color
          else
            textcolor = nil
          end
        else
          surf.buffer[((j - 1) * surf.width + px - 1) * 3 + 1] = lines[j]:sub(i, i)
          surf.buffer[((j - 1) * surf.width + px - 1) * 3 + 2] = backcolor
          surf.buffer[((j - 1) * surf.width + px - 1) * 3 + 3] = textcolor
          px = px + 1
        end
        i = i + 1
      end
    end
    return surf
  else
    local width = #lines[1]
    local surf = surface.create(width, height)
    for j=1,height,1 do
      for i=1,width,1 do
        local color = tonumber(lines[j]:sub(i, i), 16)
        if color then
          surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 2] = 2 ^ color
        end
      end
    end
    return surf
  end
end

function _colorToHex(color)
  if color then
    return string.format("%x", math.log(color)/math.log(2))
  else
    return " "
  end
end

function save(surf, path, type)
  type = type or "nft"
  local f = fs.open(path, "w")
  if type == "nfp" then
    for j=1,surf.height,1 do
      if j > 1 then f.write("\n") end
      for i=1,surf.width,1 do
        f.write(colorToHex(surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 2]))
      end
    end
  elseif type == "nft" then
    for j=1,surf.height,1 do
      backcolor = -1
      textcolor = -1
      if j > 1 then f.write("\n") end
      for i=1,surf.width,1 do
        if backcolor ~= surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 2] then
          f.write(string.char(30))
          backcolor = surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 2]
          f.write(_colorToHex(backcolor))
        end
        if textcolor ~= surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 3] then
          f.write(string.char(31))
          textcolor = surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 3]
          f.write(_colorToHex(textcolor))
        end
        if surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 1] then
          f.write(surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 1])
        else
          f.write(" ")
        end
      end
    end
  end
  f.close()
end

function drawToDisplay(surf, display, x, y, sx1, sy1, sx2, sy2)
  x = x or 1
  y = y or 1
  sx1 = sx1 or 1
  sy1 = sy1 or 1
  sx2 = sx2 or surf.width
  sy2 = sy2 or surf.height
  local cmd = { }
  local str = ""
  local backcolor = 0
  local textcolor = 0

  for j=sy1,sy2,1 do
    cmd[#cmd + 1] = 1
    cmd[#cmd + 1] = y + j - sy1
    for i=sx1,sx2,1 do
      if surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 2] ~= backcolor then
        backcolor = surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 2]
        if str ~= "" then
          cmd[#cmd + 1] = 4
          cmd[#cmd + 1] = str
          str = ""
        end
        cmd[#cmd + 1] = 2
        cmd[#cmd + 1] = backcolor
      end
      if surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 3] ~= textcolor then
        textcolor = surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 3]
        if str ~= "" then
          cmd[#cmd + 1] = 4
          cmd[#cmd + 1] = str
          str = ""
        end
        cmd[#cmd + 1] = 3
        cmd[#cmd + 1] = textcolor
      end
      str = str..surf.buffer[((j - 1) * surf.width + i - 1) * 3 + 1]
    end
    cmd[#cmd + 1] = 4
    cmd[#cmd + 1] = str
    str = ""
  end

  for i=1,#cmd/2,1 do
    local c = cmd[(i - 1) * 2 + 1]
    local a = cmd[(i - 1) * 2 + 2]
    if c == 1 then
      display.setCursorPos(x, a)
    elseif c == 2 then
      display.setBackgroundColor(a)
    elseif c == 3 then
      display.setTextColor(a)
    elseif c == 4 then
      display.write(a)
    end
  end
end

function clear(surf, char, backcolor, textcolor)
  for i=1,surf.width*surf.height,1 do
    surf.buffer[(i - 1) * 3 + 1] = char
    surf.buffer[(i - 1) * 3 + 2] = backcolor
    surf.buffer[(i - 1) * 3 + 3] = textcolor
  end
end

function drawPixel(surf, x, y, char, backcolor, textcolor)
  if x < 1 or y < 1 or x > surf.width or y > surf.height then return end
  if char or surf.overwrite then
    surf.buffer[((y - 1) * surf.width + x - 1) * 3 + 1] = char
  end
  if backcolor or surf.overwrite then
    surf.buffer[((y - 1) * surf.width + x - 1) * 3 + 2] = backcolor
  end
  if textcolor or surf.overwrite then
    surf.buffer[((y - 1) * surf.width + x - 1) * 3 + 3] = textcolor
  end
end

function getPixel(surf, x, y)
  if x < 1 then return end
  if x > surf.width then return end
  if y < 1 then return end
  if y > surf.height then return end
  return surf.buffer[((y - 1) * surf.width + x - 1) * 3 + 1], surf.buffer[((y - 1) * surf.width + x - 1) * 3 + 2], surf.buffer[((y - 1) * surf.width + x - 1) * 3 + 3]
end

function drawText(surf, x, y, text, backcolor, textcolor)
  local px = x
  for i=1,#text,1 do
    if text:sub(i, i) ~= "\n" then
      surf:drawPixel(x, y, text:sub(i, i), backcolor, textcolor)
    else
      x = px - 1
      y = y + 1
    end
    x = x + 1
  end
end

function drawLine(surf, x1, y1, x2, y2, char, backcolor, textcolor)
  local delta_x = x2 - x1
  local ix = delta_x > 0 and 1 or -1
  delta_x = 2 * math.abs(delta_x)
  local delta_y = y2 - y1
  local iy = delta_y > 0 and 1 or -1
  delta_y = 2 * math.abs(delta_y)
  surf:drawPixel(x1, y1, char, backcolor, textcolor)
  if delta_x >= delta_y then
    local error = delta_y - delta_x / 2
    while x1 ~= x2 do
      if (error >= 0) and ((error ~= 0) or (ix > 0)) then
        error = error - delta_x
        y1 = y1 + iy
      end
      error = error + delta_y
      x1 = x1 + ix
      surf:drawPixel(x1, y1, char, backcolor, textcolor)
    end
  else
    local error = delta_x - delta_y / 2
    while y1 ~= y2 do
      if (error >= 0) and ((error ~= 0) or (iy > 0)) then
        error = error - delta_y
        x1 = x1 + ix
      end
      error = error + delta_x
      y1 = y1 + iy
      surf:drawPixel(x1, y1, char, backcolor, textcolor)
    end
  end
end

function drawRect(surf, x1, y1, x2, y2, char, backcolor, textcolor)
  surf:drawLine(x1, y1, x2, y1, char, backcolor, textcolor)
  surf:drawLine(x1, y1, x1, y2, char, backcolor, textcolor)
  surf:drawLine(x1, y2, x2, y2, char, backcolor, textcolor)
  surf:drawLine(x2, y1, x2, y2, char, backcolor, textcolor)
end

function fillRect(surf, x1, y1, x2, y2, char, backcolor, textcolor)
  if x2 < x1 then
    local temp = x1
    x1 = x2
    x2 = temp
  end
  if y2 < y1 then
    local temp = y1
    y1 = y2
    y2 = temp
  end
  if x2 < 1 then return end
  if x1 > surf.width then return end
  if y2 < 1 then return end
  if y1 > surf.width then return end
  if x1 < 1 then x1 = 1 end
  if x2 > surf.width then x2 = surf.width end
  if y1 < 1 then y1 = 1 end
  if y2 > surf.width then y2 = surf.height end

  if char or surf.overwrite then
    for y=y1,y2,1 do
      for x=x1,x2,1 do
        surf.buffer[((y-1) * surf.width + (x-1)) * 3 + 1] = char
      end
    end
  end
  if backcolor or surf.overwrite then
    for y=y1,y2,1 do
      for x=x1,x2,1 do
        surf.buffer[((y-1) * surf.width + (x-1)) * 3 + 2] = backcolor
      end
    end
  end
  if textcolor or surf.overwrite then
    for y=y1,y2,1 do
      for x=x1,x2,1 do
        surf.buffer[((y-1) * surf.width + (x-1)) * 3 + 3] = textcolor
      end
    end
  end
end

function drawSurface(surf, x, y, surf2)
  for j=1,surf2.height,1 do
    for i=1,surf2.width,1 do
      surf:drawPixel(i + x - 1, j + y - 1, surf2.buffer[((j-1) * surf2.width + (i-1)) * 3 + 1], surf2.buffer[((j-1) * surf2.width + (i-1)) * 3 + 2], surf2.buffer[((j-1) * surf2.width + (i-1)) * 3 + 3])
    end
  end
end

function drawSurfacePart(surf, x, y, sx1, sy1, sx2, sy2, surf2)
  if sx2 < sx1 then
    local temp = sx1
    sx1 = sx2
    sx2 = temp
  end
  if sy2 < sy1 then
    local temp = sy1
    sy1 = sy2
    sy2 = temp
  end
  if sx2 < 1 then return end
  if sx1 > surface.width then return end
  if sy2 < 1 then return end
  if sy1 > surface.width then return end
  if sx1 < 1 then sx1 = 1 end
  if sx2 > surface.width then sx2 = surface.width end
  if sy1 < 1 then sy1 = 1 end
  if sy2 > surface.width then sy2 = surface.height end

  for j=sy1,sy2,1 do
    for i=sx1,sx2,1 do
      surf:drawPixel(x + i - sx1, y + j - sy1, surf2.buffer[((j-1) * surf2.width + (i-1)) * 3 + 1], surf2.buffer[((j-1) * surf2.width + (i-1)) * 3 + 2], surf2.buffer[((j-1) * surf2.width + (i-1)) * 3 + 3])
    end
  end
end

function drawSurfaceScaled(surf, x1, y1, x2, y2, surf2)
  local x = 0
  local width = 0
  local xinv = false
  local y = 0
  local height = 0
  local yinv = false
  if x2 >= x1 then
    x = x1
    width = x2 - x1 + 1
  else
    x = x2
    width = x1 - x2 + 1
    xinv = true
  end
  if y2 >= y1 then
    y = y1
    height = y2 - y1 + 1
  else
    y = y2
    height = y1 - y2 + 1
    yinv = true
  end
  local xscale = width / surf2.width
  local yscale = height / surf2.height

  for j=1,height,1 do
    for i=1,width,1 do
      local ii = i
      local jj = j
      if xinv then ii = width - ii + 1 end
      if yinv then jj = height - jj + 1 end
      local px = math.floor((ii - 0.5) / xscale) + 1
      local py = math.floor((jj - 0.5) / yscale) + 1
      surf:drawPixel(x + i - 1, y + j - 1, surf2.buffer[((py-1) * surf2.width + (px-1)) * 3 + 1], surf2.buffer[((py-1) * surf2.width + (px-1)) * 3 + 2], surf2.buffer[((py-1) * surf2.width + (px-1)) * 3 + 3])
    end
  end
end