CEF Graphics

---

CEF (Chromium Embedded Framework) supplies the web browser used inside an X-Plane plugin window. The page is ordinary HTML, CSS, and JavaScript. X-Plane owns and renders the browser; Lua creates and controls its window.

##  Minimal Code for CEF:


--[[ XLua 2.0 ]]

local myBrowserWindow = nil

--======================================================================================================================
--  URL Resolution Utilities.   These make it easy to specify a relative URL from your Lua to HTML assets,  

--  e.g.  XPLMWindowSetURL(myBrowserWindow,     relURL("html/index.html"))

--  Without these, you'd have to provide nasty, absolute file paths, which differ in format on Mac and windows,
--  UGGGHH.  Just use the one function  "relURL(rel_path)",   and call it a day!
--======================================================================================================================

local function encode_url_path(path)
    -- Encode every byte except URL-safe path characters.
    return path:gsub("([^%w%-%._~/:])", function(character)
        return string.format("%%%02X", string.byte(character))
    end)
end

------------------------------------------------------------------------------------------------------------------------

local function path_to_file_url(path)
    -- File URLs always use forward slashes, including on Windows.
    path = path:gsub("\\", "/")
    path = encode_url_path(path)

    if path:match("^%a:/") then
        -- Windows drive path: C:/X-Plane/...
        return "file:///" .. path
    elseif path:sub(1, 2) == "//" then
        -- Windows UNC path: //server/share/...
        return "file:" .. path
    elseif path:sub(1, 1) == "/" then
        -- macOS/Linux absolute path. "file://" + "/..." gives file:///...
        return "file://" .. path
    end

    error("Cannot create file URL from a relative path: " .. path)
end

------------------------------------------------------------------------------------------------------------------------

local aircraft              =   XPLMGetNthAircraftModel(0)
local aircraft_path         =   aircraft.outPath
local aircraft_directory    =   aircraft_path:match("^(.*[/\\])")

assert(aircraft_directory, "Could not determine aircraft directory")

local project_directory     =   aircraft_directory .. "plugins/xlua2/scripts/tomcef/"

------------------------------------------------------------------------------------------------------------------------
--  USE THE FUNCTION BELOW, NOT the ones above, they're helpers to this one.  Pass a relative path FROM this Lua file to
--  your HTML files.

local function relURL(relative_path)
    return path_to_file_url(project_directory .. relative_path)
end

--======================================================================================================================
--                                      LIFECYCLE CALLBACKS
--======================================================================================================================

function XPluginStart()

    myBrowserWindow = XPLMCreateWindowEx({
        left                        =   100,
        top                         =   600,
        right                       =   700,
        bottom                      =   200,
        visible                     =   true,     
        decorateAsFloatingWindow    =   XPLMWindowDecoration.xplm_WindowDecorationRoundRectangle,
        windowContentType           =   XPLMWindowContentType.xplm_WindowContentTypeBrowser
    })

    XPLMSetWindowTitle  (myBrowserWindow,   "hello world test")      
--  XPLMWindowSetURL    (myBrowserWindow,   relURL("site/hello_world.html"))

    return myBrowserWindow ~= nil
end

function XPluginEnable()
    return true
end
-- An aircraft XLua module is executed directly; XPluginStart is not dispatched.


function XPluginDisable()
end

function XPluginStop()
    if myBrowserWindow then XPLMDestroyWindow(myBrowserWindow); myBrowserWindow = nil end
end


function aircraft_unload()
end

function XPluginReceiveMessage(from, message, parameter)
end