Update README.md

README.md

@@ -14,6 +14,7 @@ AHI uses the Interception driver by Francisco Lopez
 5. Run the example script
 
 # Usage
+## Initializing the Library
 Include the library
 ```
 #Persistent ; (Interception hotkeys do not stop AHK from exiting, so use this)
@@ -25,13 +26,61 @@ Initialize the library
 Interception := AutoHotInterception_Init()
 ```
 
+## Context mode
+Context mode is so named as it takes advantage of AutoHotkey's [Context Sensitive Hotkeys](https://autohotkey.com/docs/Hotkeys.htm#Context).  
+In AHK, you can wrap your hotkeys in a block like so:
+```
+#if myVariable == 1
+F1::Msgbox You Pressed F1
+#if
+```
+This hotkey would only fire if the `myVariable` was 1.  
+In context mode, you subscribe to a keyboard, and any time events for that keyboard are just about to happen, then AHI fires your callback, and you set this variable to `1` the hotkey is enabled. After your hotkey fires, AHI fires the callback again and the variable gets set back to `0`.  
+
+### Step 1
+Register your callback with AHI  
+```
+VID := 0x04F2, PID := 0x0112
+Interception.SetContextCallback(VID, PID, Func("SetKb1Context"))
+```
+
+### Step 2
+Create your callback function, and set the context variable to the value of `state`
+```
+SetKb1Context(state){
+	global isKeyboard1Active
+	Sleep 0		; We seem to need this for hotstrings to work, not sure why
+	isKeyboard1Active := state
+}
+```
+
+### Step 3
+Create your hotkeys, wrapped in an `#if` block for that context variable
+```
+#if isKeyboard1Active
+::aaa::JACKPOT
+1:: 
+	ToolTip % "KEY DOWN EVENT @ " A_TickCount
+	return
+	
+1 up::
+	ToolTip % "KEY UP EVENT @ " A_TickCount
+	return
+#if
+```
+
+## Subscription mode
+In Subscription mode, you bypass AHK's hotkey system completely, and Interception notifies you og key events via callbacks.  
+
 Subscribe to a key on a specific keyboard
+`SubscribeKey(<scanCode>, <block>, <callback>, <VID>, <PID>`
 ```
+VID := 0x04F2, PID := 0x0112
 Interception.SubscribeKey(GetKeySC("1"), true, Func("KeyEvent"), VID, PID)
 return
 ```
 
-Callback function is passed state `0 (released) ` or `1` (pressed)
+Callback function is passed state `0` (released) or `1` (pressed)
 ```
 KeyEvent(state){
 	ToolTip % "State: " state