Lyqyd's Framebuffer API modified

--[[
    This is the Framebuffer API made by Lyqyd, but I modified it with a few, non-standard term functions.
    pastebin get sMVQZJcx framebuffer
--]]

--[[
The MIT License (MIT)

Copyright (c) 2013 Lyqyd

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
--]]

function new(_sizeX, _sizeY, _color, _xOffset, _yOffset)
    local redirect = {buffer = {text = {}, textColor = {}, backColor = {}, cursorX = 1, cursorY = 1, cursorBlink = false, curTextColor = "0", curBackColor = "f", sizeX = _sizeX or 51, sizeY = _sizeY or 19, color = _color, xOffset = _xOffset or 0, yOffset = _yOffset or 0}}
    local function doWrite(text, textColor, backColor)
        local pos = redirect.buffer.cursorX
        if redirect.buffer.cursorY > redirect.buffer.sizeY or redirect.buffer.cursorY < 1 then
            redirect.buffer.cursorX = pos + #text
            return
        end
        local writeText, writeTC, writeBC
        if pos + #text <= 1 then
            --skip entirely.
            redirect.buffer.cursorX = pos + #text
            return
        elseif pos < 1 then
            --adjust text to fit on screen starting at one.
            local len = math.abs(redirect.buffer.cursorX) + 2
            writeText = string.sub(text, len)
            writeTC = textColor and string.sub(textColor, len) or nil
            writeBC = textColor and string.sub(backColor, len) or nil
            redirect.buffer.cursorX = 1
        elseif pos > redirect.buffer.sizeX then
            --if we're off the edge to the right, skip entirely.
            redirect.buffer.cursorX = pos + #text
            return
        else
            writeText = text
            writeTC = textColor or nil
            writeBC = backColor or nil
        end
        local lineText = redirect.buffer.text[redirect.buffer.cursorY]
        local lineColor = redirect.buffer.textColor[redirect.buffer.cursorY]
        local lineBack = redirect.buffer.backColor[redirect.buffer.cursorY]
        local preStop = redirect.buffer.cursorX - 1
        local preStart = math.min(1, preStop)
        local postStart = redirect.buffer.cursorX + string.len(writeText)
        local postStop = redirect.buffer.sizeX
        redirect.buffer.text[redirect.buffer.cursorY] = string.sub(lineText, preStart, preStop)..writeText..string.sub(lineText, postStart, postStop)
        if textColor then redirect.buffer.textColor[redirect.buffer.cursorY] = string.sub(lineColor, preStart, preStop)..writeTC..string.sub(lineColor, postStart, postStop) end
        if backColor then redirect.buffer.backColor[redirect.buffer.cursorY] = string.sub(lineBack, preStart, preStop)..writeBC..string.sub(lineBack, postStart, postStop) end
        redirect.buffer.cursorX = pos + string.len(text)
    end
    redirect.write = function(text)
        local text = tostring(text)
        doWrite(text, string.rep(redirect.buffer.curTextColor, #text), string.rep(redirect.buffer.curBackColor, #text))
    end
    redirect.blit = function(text, textColor, backColor)
        if type(text) ~= "string" or type(textColor) ~= "string" or type(backColor) ~= "string" then
            error("Expected string, string, string", 2)
        end
        if #textColor ~= #text or #backColor ~= #text then
            error("Arguments must be the same length", 2)
        end
        doWrite(text, textColor, backColor)
    end
    redirect.clear = function()
        for i=1, redirect.buffer.sizeY do
            redirect.buffer.text[i] = string.rep(" ", redirect.buffer.sizeX)
            redirect.buffer.textColor[i] = string.rep(redirect.buffer.curTextColor, redirect.buffer.sizeX)
            redirect.buffer.backColor[i] = string.rep(redirect.buffer.curBackColor, redirect.buffer.sizeX)
        end
    end
    redirect.clearLine = function()
        redirect.buffer.text[redirect.buffer.cursorY] = string.rep(" ", redirect.buffer.sizeX)
        redirect.buffer.textColor[redirect.buffer.cursorY] = string.rep(redirect.buffer.curTextColor, redirect.buffer.sizeX)
        redirect.buffer.backColor[redirect.buffer.cursorY] = string.rep(redirect.buffer.curBackColor, redirect.buffer.sizeX)
    end
    redirect.getCursorPos = function()
        return redirect.buffer.cursorX, redirect.buffer.cursorY
    end
    redirect.setCursorPos = function(x, y)
        redirect.buffer.cursorX = math.floor(tonumber(x) or redirect.buffer.cursorX)
        redirect.buffer.cursorY = math.floor(tonumber(y) or redirect.buffer.cursorY)
    end
    redirect.setCursorBlink = function(b)
        redirect.buffer.cursorBlink = b
    end
    redirect.getSize = function()
        return redirect.buffer.sizeX, redirect.buffer.sizeY
    end
    redirect.scroll = function(n)
        n = tonumber(n) or 1
        if n > 0 then
            for i = 1, redirect.buffer.sizeY - n do
                if redirect.buffer.text[i + n] then
                    redirect.buffer.text[i] = redirect.buffer.text[i + n]
                    redirect.buffer.textColor[i] = redirect.buffer.textColor[i + n]
                    redirect.buffer.backColor[i] = redirect.buffer.backColor[i + n]
                end
            end
            for i = redirect.buffer.sizeY, redirect.buffer.sizeY - n + 1, -1 do
                redirect.buffer.text[i] = string.rep(" ", redirect.buffer.sizeX)
                redirect.buffer.textColor[i] = string.rep(redirect.buffer.curTextColor, redirect.buffer.sizeX)
                redirect.buffer.backColor[i] = string.rep(redirect.buffer.curBackColor, redirect.buffer.sizeX)
            end
        elseif n < 0 then
            for i = redirect.buffer.sizeY, math.abs(n) + 1, -1 do
                if redirect.buffer.text[i + n] then
                    redirect.buffer.text[i] = redirect.buffer.text[i + n]
                    redirect.buffer.textColor[i] = redirect.buffer.textColor[i + n]
                    redirect.buffer.backColor[i] = redirect.buffer.backColor[i + n]
                end
            end
            for i = 1, math.abs(n) do
                redirect.buffer.text[i] = string.rep(" ", redirect.buffer.sizeX)
                redirect.buffer.textColor[i] = string.rep(redirect.buffer.curTextColor, redirect.buffer.sizeX)
                redirect.buffer.backColor[i] = string.rep(redirect.buffer.curBackColor, redirect.buffer.sizeX)
            end
        end
    end
    redirect.getTextColor = function()
        return 2 ^ tonumber(redirect.buffer.curTextColor, 16)
    end
    redirect.getTextColour = redirect.getTextColor
    redirect.setTextColor = function(clr)
        if clr and clr <= 32768 and clr >= 1 then
            if redirect.buffer.color then
                redirect.buffer.curTextColor = string.format("%x", math.floor(math.log(clr) / math.log(2)))
            elseif clr == 1 or clr == 32768 then
                redirect.buffer.curTextColor = string.format("%x", math.floor(math.log(clr) / math.log(2)))
            else
                return nil, "Colour not supported"
            end
        end
    end
    redirect.setTextColour = redirect.setTextColor
    redirect.getBackgroundColor = function()
        return 2 ^ tonumber(redirect.buffer.curBackColor, 16)
    end
    redirect.getBackgroundColour = redirect.getBackgroundColor
    redirect.setBackgroundColor = function(clr)
        if clr and clr <= 32768 and clr >= 1 then
            if redirect.buffer.color then
                redirect.buffer.curBackColor = string.format("%x", math.floor(math.log(clr) / math.log(2)))
            elseif clr == 32768 or clr == 1 then
                redirect.buffer.curBackColor = string.format("%x", math.floor(math.log(clr) / math.log(2)))
            else
                return nil, "Colour not supported"
            end
        end
    end
    redirect.setBackgroundColour = redirect.setBackgroundColor
    redirect.isColor = function()
        return redirect.buffer.color == true
    end
    redirect.isColour = redirect.isColor
    redirect.render = function(inputBuffer)
        for i = 1, redirect.buffer.sizeY do
            redirect.buffer.text[i] = inputBuffer.text[i]
            redirect.buffer.textColor[i] = inputBuffer.textColor[i]
            redirect.buffer.backColor[i] = inputBuffer.backColor[i]
        end
    end
    redirect.twrite = function(text)
        local text = tostring(text)
        doWrite(text, string.rep(redirect.buffer.curTextColor, #text), nil)
    end
    redirect.bwrite = function(text)
        local text = tostring(text)
        doWrite(text, nil, string.rep(redirect.buffer.curBackColor, #text))
    end
    redirect.getCharData = function(_x,_y)
        local x,y = tonumber(_x) or redirect.cursorX, tonumber(_y) or redirect.cursorY
        local output = {}
        output.text = redirect.buffer.text[y]:sub(x,x)
        output.textColor = redirect.buffer.text[y]:sub(x,x)
        output.backColor = redirect.buffer.text[y]:sub(x,x)
        return output
    end
    redirect.setBounds = function(x_min, y_min, x_max, y_max)
        redirect.buffer.minX = x_min
        redirect.buffer.maxX = x_max
        redirect.buffer.minY = y_min
        redirect.buffer.maxY = y_max
    end
    redirect.setBounds(1, 1, redirect.buffer.sizeX, redirect.buffer.sizeY)
    redirect.clear()
    return redirect
end

function draw(buffer, current)
    for i = buffer.minY, buffer.maxY do
        term.setCursorPos(buffer.minX + buffer.xOffset, i + buffer.yOffset)
        if (current and (buffer.text[i] ~= current.text[i] or buffer.textColor[i] ~= current.textColor[i] or buffer.backColor[i] ~= current.backColor[i])) or not current then
            if term.blit then
                term.blit(buffer.text[i], buffer.textColor[i], buffer.backColor[i])
            else
                local lineEnd = false
                local offset = buffer.minX
                while not lineEnd do
                    local limit = buffer.maxX - offset + 1
                    local textColorString = string.match(string.sub(buffer.textColor[i], offset), string.sub(buffer.textColor[i], offset, offset).."*")
                    local backColorString = string.match(string.sub(buffer.backColor[i], offset), string.sub(buffer.backColor[i], offset, offset).."*")
                    term.setTextColor(2 ^ tonumber(string.sub(textColorString, 1, 1), 16))
                    term.setBackgroundColor(2 ^ tonumber(string.sub(backColorString, 1, 1), 16))
                    term.write(string.sub(buffer.text[i], offset, offset + math.min(#textColorString, #backColorString, limit) - 1))
                    offset = offset + math.min(#textColorString, #backColorString, limit)
                    if offset > buffer.maxX then lineEnd = true end
                end
            end
            if current then
                current.text[i] = buffer.text[i]
                current.textColor[i] = buffer.textColor[i]
                current.backColor[i] = buffer.backColor[i]
            end
        end
    end
    term.setCursorPos(buffer.cursorX + buffer.xOffset, buffer.cursorY + buffer.yOffset)
    term.setTextColor(2 ^ tonumber(buffer.curTextColor, 16))
    term.setBackgroundColor(2 ^ tonumber(buffer.curBackColor, 16))
    term.setCursorBlink(buffer.cursorBlink)
    return current
end