Mirror a ComputerCraft computer screen to a monitor

mirror.lua

-- SPDX-FileCopyrightText: 2017 Daniel Ratcliffe, 2025 minerobber
--
-- SPDX-License-Identifier: LicenseRef-CCPL

local function printUsage()
    local programName = arg[0] or fs.getName(shell.getRunningProgram())
    print("Usage: " .. programName .. " <name> <program> <arguments>")
    return
end-- SPDX-FileCopyrightText: 2017 Daniel Ratcliffe
--
-- SPDX-License-Identifier: LicenseRef-CCPL

local function printUsage()
    local programName = arg[0] or fs.getName(shell.getRunningProgram())
    print("Usage:")
    print("  " .. programName .. " <name> <program> <arguments>")
    --print("  " .. programName .. " scale <name> <scale>")
    return
end

local tArgs = { ... }
if #tArgs < 2 then
    if tArgs[1]=="define" then
        -- shell completion
        local completion = require("cc.shell.completion")
        shell.setCompletionFunction(shell.getRunningProgram(), completion.build(
            { completion.peripheral, true },
            { completion.programWithArgs, 3, many=true }
        ))
        -- settings
        settings.define("mirror.fill_character", {
            description = "The character that fills background of the monitor outside the terminal window.";
            default = "\127";
            type = "string";
        })
        settings.define("mirror.fill_fg", {
            description = "The color to fill the foreground with, as a hex color.";
            default = "0";
            type = "string";
        })
        settings.define("mirror.fill_bg", {
            description = "The color to fill the background with, as a hex color.";
            default = "f";
            type = "string";
        })
        return
    end

    printUsage()
    return
end

local sName = tArgs[1]
if peripheral.getType(sName) ~= "monitor" then
    print("No monitor named " .. sName)
    return
end

local termWidth, termHeight = term.getSize()
peripheral.call(sName, "setTextScale", 1)
local monWidth, monHeight = peripheral.call(sName, "getSize")
local monScale = math.min(math.floor((monWidth / termWidth) * 2) / 2, math.floor((monHeight / termHeight) * 2) / 2)
peripheral.call(sName, "setTextScale", monScale)
monWidth, monHeight = peripheral.call(sName, "getSize")

local sProgram = tArgs[2]

local sPath = shell.resolveProgram(sProgram)
if sPath == nil then
    print("No such program: " .. sProgram)
    return
end

print("Mirroring " .. sProgram .. " on monitor " .. sName .. "...")
sleep(3)

local monOffsetX = math.floor((monWidth - termWidth)/2)
local monOffsetY = math.floor((monHeight - termHeight)/2)
local previousTerm
local redirect = setmetatable({
    setCursorPos = function(x, y)
        if not previousTerm then error("attempt to set cursor position before redirect") end
        peripheral.call(sName, "setCursorPos", x+monOffsetX, y+monOffsetY)
        return previousTerm.setCursorPos(x, y)
    end;
},{
    __index=function(_, k)
        return function(...)
            if not previousTerm then return term[k](...) end
            peripheral.call(sName, k, ...)
            return previousTerm[k](...)
        end
    end;
})

for y=1,monHeight do
    peripheral.call(sName, "setCursorPos", 1, y)
    peripheral.call(sName, "blit", settings.get("mirror.fill_character","\127"):sub(1,1):rep(monWidth), settings.get("mirror.fill_fg","0"):sub(1,1):rep(monWidth), settings.get("mirror.fill_bg","f"):rep(monWidth))
end

local win = window.create(redirect, 1, 1, termWidth, termHeight, false)
previousTerm = term.redirect(win)
win.setVisible(true)
term.clear()
term.setCursorPos(1,1)

local co = coroutine.create(function()
    (shell.execute or shell.run)(sProgram, table.unpack(tArgs, 3))
end)

local function resume(...)
    local ok, param = coroutine.resume(co, ...)
    if not ok then
        printError(param)
    end
    return param
end

local timers = {}

local ok, param = pcall(function()
    local sFilter = resume()
    while coroutine.status(co) ~= "dead" do
        local tEvent = table.pack(os.pullEventRaw())
        if sFilter == nil or tEvent[1] == sFilter or tEvent[1] == "terminate" then
            sFilter = resume(table.unpack(tEvent, 1, tEvent.n))
        end
        if coroutine.status(co) ~= "dead" and (sFilter == nil or sFilter == "mouse_click") then
            if tEvent[1] == "monitor_touch" and tEvent[2] == sName then
                timers[os.startTimer(0.1)] = { tEvent[3], tEvent[4] }
                sFilter = resume("mouse_click", 1, table.unpack(tEvent, 3, tEvent.n))
            end
        end
        if coroutine.status(co) ~= "dead" and (sFilter == nil or sFilter == "term_resize") then
            if tEvent[1] == "monitor_resize" and tEvent[2] == sName then
                sFilter = resume("term_resize")
            end
        end
        if coroutine.status(co) ~= "dead" and (sFilter == nil or sFilter == "mouse_up") then
            if tEvent[1] == "timer" and timers[tEvent[2]] then
                sFilter = resume("mouse_up", 1, table.unpack(timers[tEvent[2]], 1, 2))
                timers[tEvent[2]] = nil
            end
        end
    end
end)

term.redirect(previousTerm)
term.clear()
term.setCursorPos(1,1)
if not ok then
    printError(param)
end


local tArgs = { ... }
if #tArgs < 2 then
    if tArgs[1]=="define" then
        -- shell completion
        local completion = require("cc.shell.completion")
        shell.setCompletionFunction(shell.getRunningProgram(), completion.build(
            { completion.peripheral, true },
            { completion.programWithArgs, 3, many=true }
        ))
        -- settings
        settings.define("mirror.fill_character", {
            description = "The character that fills background of the monitor outside the terminal window.";
            default = "\127";
            type = "string";
        })
        settings.define("mirror.fill_fg", {
            description = "The color to fill the foreground with, as a hex color.";
            default = "0";
            type = "string";
        })
        settings.define("mirror.fill_bg", {
            description = "The color to fill the background with, as a hex color.";
            default = "f";
            type = "string";
        })
        return
    end

    printUsage()
    return
end

local sName = tArgs[1]
if peripheral.getType(sName) ~= "monitor" then
    print("No monitor named " .. sName)
    return
end

local termWidth, termHeight = term.getSize()
local monWidth, monHeight = peripheral.call(sName, "getSize")
if monWidth<termWidth or monHeight<termHeight then
    print("Monitor " .. sName .. " too small")
    return
end

local sProgram = tArgs[2]

local sPath = shell.resolveProgram(sProgram)
if sPath == nil then
    print("No such program: " .. sProgram)
    return
end

print("Mirroring " .. sProgram .. " on monitor " .. sName .. "...")
sleep(3)

local monOffsetX = math.floor((monWidth - termWidth)/2)
local monOffsetY = math.floor((monHeight - termHeight)/2)
local previousTerm
local redirect = setmetatable({
    setCursorPos = function(x, y)
        if not previousTerm then error("attempt to set cursor position before redirect") end
        peripheral.call(sName, "setCursorPos", x+monOffsetX, y+monOffsetY)
        return previousTerm.setCursorPos(x, y)
    end;
},{
    __index=function(_, k)
        return function(...)
            if not previousTerm then return term[k](...) end
            peripheral.call(sName, k, ...)
            return previousTerm[k](...)
        end
    end;
})

for y=1,monHeight do
    peripheral.call(sName, "setCursorPos", 1, y)
    peripheral.call(sName, "blit", settings.get("mirror.fill_character","\127"):sub(1,1):rep(monWidth), settings.get("mirror.fill_fg","0"):sub(1,1):rep(monWidth), settings.get("mirror.fill_bg","f"):rep(monWidth))
end

local win = window.create(redirect, 1, 1, termWidth, termHeight, false)
previousTerm = term.redirect(win)
win.setVisible(true)
term.clear()
term.setCursorPos(1,1)

local co = coroutine.create(function()
    (shell.execute or shell.run)(sProgram, table.unpack(tArgs, 3))
end)

local function resume(...)
    local ok, param = coroutine.resume(co, ...)
    if not ok then
        printError(param)
    end
    return param
end

local timers = {}

local ok, param = pcall(function()
    local sFilter = resume()
    while coroutine.status(co) ~= "dead" do
        local tEvent = table.pack(os.pullEventRaw())
        if sFilter == nil or tEvent[1] == sFilter or tEvent[1] == "terminate" then
            sFilter = resume(table.unpack(tEvent, 1, tEvent.n))
        end
        if coroutine.status(co) ~= "dead" and (sFilter == nil or sFilter == "mouse_click") then
            if tEvent[1] == "monitor_touch" and tEvent[2] == sName then
                timers[os.startTimer(0.1)] = { tEvent[3], tEvent[4] }
                sFilter = resume("mouse_click", 1, table.unpack(tEvent, 3, tEvent.n))
            end
        end
        if coroutine.status(co) ~= "dead" and (sFilter == nil or sFilter == "term_resize") then
            if tEvent[1] == "monitor_resize" and tEvent[2] == sName then
                sFilter = resume("term_resize")
            end
        end
        if coroutine.status(co) ~= "dead" and (sFilter == nil or sFilter == "mouse_up") then
            if tEvent[1] == "timer" and timers[tEvent[2]] then
                sFilter = resume("mouse_up", 1, table.unpack(timers[tEvent[2]], 1, 2))
                timers[tEvent[2]] = nil
            end
        end
    end
end)

term.redirect(previousTerm)
term.clear()
term.setCursorPos(1,1)
if not ok then
    printError(param)
end