Graphix API

--2D Graphics API for Computercraft Computers
--Author: Andrew Lalis, andrewlalisofficial@gmail.com

--Current peripheral to draw to
local m
--Determines if the peripheral is a monitor or computer screen.
local isMonitor
local buttonLoopActive = false

--Holds all registered buttons.
local buttons = {}

--Clears the screen.
function clear(bc)
    m.setBackgroundColor(bc)
    m.clear()
end

--Sets the current peripheral.
function setTarget(target,isMon)
    m = target
    isMonitor = isMon
end

--Wraps text
function wrap(str, limit)
  limit = limit or 72
  local here = 1
  local buf = ""
  local t = {}
  str:gsub("(%s*)()(%S+)()",
  function(sp, st, word, fi)
        if fi-here > limit then
           --# Break the line
           here = st
           table.insert(t, buf)
           buf = word
        else
           buf = buf..sp..word  --# Append
        end
  end)
  --# Tack on any leftovers
  if(buf ~= "") then
        table.insert(t, buf)
  end
  return t
end

--Fills a box with a color
function fillBox(x,y,width,height,bc)
    m.setBackgroundColor(bc)
    for i=x,width+x-1 do
        for k=y,height+y-1 do
            m.setCursorPos(i,k)
            m.write(" ")
        end
    end
end

--Draws a horizontal line.
function drawLineH(x1,width,y,bc)
    m.setBackgroundColor(bc)
    for x=x1,width+x1-1 do
        m.setCursorPos(x,y)
        m.write(" ")
    end
end

--Draws a vertical line.
function drawLineV(x,y1,height,bc)
    m.setBackgroundColor(bc)
    for y=y1,height+y1-1 do
        m.setCursorPos(x,y)
        m.write(" ")
    end
end

--Draws border box.
function drawBorder(x1,y1,width,height,bc,fillColor)
    fillBox(x1+1,y1+1,width-2,height-2,fillColor)
    drawLineH(x1,width,y1,bc)
    drawLineH(x1,width,y1+height-1,bc)
    drawLineV(x1,y1,height,bc)
    drawLineV(x1+width-1,y1,height,bc)
end

--Creates a text box with a title and border.
function drawTextBox(title,title_tc,title_bc,body,body_tc,body_bc,x,y,width,height)
    if (height == nil) then
        height = #(wrap(body,width)) + 2
    end
    drawBorder(x,y,width,height,title_bc,body_bc)
    writeText(title,x+1,y,title_tc,title_bc)
    writeTextWrapped(body,x+1,y+1,width-2,body_tc,body_bc)
end

--Writes a block of text wrapped in an area.
function writeTextWrapped(text,x,y,width,tc,bc)
    local wrapped = wrap(text, width)
    fillBox(x,y,width,#wrapped,bc)
    m.setTextColor(tc)
    for i=1,#wrapped do
        m.setCursorPos(x,y+i-1)
        m.write(wrapped[i])
    end
end

--Writes text starting at given coordinates.
function writeText(text,x,y,tc,bc)
    m.setCursorPos(x,y)
    m.setTextColor(tc)
    m.setBackgroundColor(bc)
    m.write(text)
end

--Writes text centered at a given point.
function writeTextCentered(text,x,y,tc,bc)
    m.setCursorPos(x-((#text)/2),y)
    m.setTextColor(tc)
    m.setBackgroundColor(bc)
    m.write(text)
end

--Gets the horizontal and vertical size of the drawing area.
function getSize()
    return m.getSize()
end

--Creates a button with a name, location, text, and function.
function createButton(name,x,y,width,height,tc,bc,bcPressed,func)
    buttons[name] = {name=name,x=x,y=y,width=width,height=height,tc=tc,bc=bc,bcPressed=bcPressed,func=func}
end

--Removes a button with a specific name.
function removeButton(name)
    table.remove(buttons, name)
end

--Draws a button on the target screen.
local function drawButton(bTable)
    local effectiveBc = bTable.bc
    if (bTable.timer ~= nil) then
        effectiveBc = bTable.bcPressed
    end
    fillBox(bTable.x,bTable.y,bTable.width,bTable.height,effectiveBc)
    writeTextCentered(bTable.name,bTable.x + bTable.width/2,bTable.y + bTable.height/2,bTable.tc,effectiveBc)
end

--Checks if a coordinate is within a button's x and y values.
local function buttonContains(bTable,x,y)
    return (x >= bTable.x and x < bTable.x+bTable.width and y >= bTable.y and y < bTable.y+bTable.height)
end

--Draws all buttons onto the screen.
function drawButtons()
    for key,button in pairs(buttons) do
        drawButton(button)
    end
end

--What to do when the user touches the monitor.
local function onMonitorTouch(side,x,y)
    for key,button in pairs(buttons) do
        if (buttonContains(button,x,y)) then
            button.timer = os.startTimer(0.25)
            drawButton(button)
            button.func(side,x,y)
        end
    end
end

--What to do when a timer is up. Set the timer to nil and redraw.
local function onTimerEvent(tId)
    for key,button in pairs(buttons) do
        if (button.timer ~= nil and button.timer == tId) then
            button.timer = nil
            drawButton(button)
        end
    end
end

--Begins an event handler for monitor and terminal touch events, and executes any buttons the user clicks on.
function buttonLoop()
    buttonLoopActive = true
    drawButtons()
    while (buttonLoopActive) do
        local event,p1,p2,p3,p4,p5 = os.pullEvent()
        if (isMonitor and event == "monitor_touch") then
            onMonitorTouch(p1,p2,p3)
        elseif (event == "mouse_click") then
            --Do the same thing for computer screens. The user changes the behaviour.
            onMonitorTouch(p1,p2,p3)
        elseif (event == "timer") then
            onTimerEvent(p1)
        end
    end
end

--Ends the button loop.
function endButtonLoop()
    buttonLoopActive = false
end