--[Request/Need help implenting]-- I want to add a virtual keyboard interface access button

[FunnyCorgi]

I think this would be good for the UI because, while it exists on mobile, not all computers have every key(e.g. pgup, pgdown, home, end, all f-keys). I think this could be a button that adds a separate section(maybe to the right of the running info section).

If you want, I can open a PR for this. I just need to know how to make each button interface with the virtual keyboard. Also, I would like help with making this so it doesn't link into the keyboard inputs unless the user has it toggled on or has pressed the button to turn it on or something.

[chschnell]

Injecting synthetic key strokes into V86 is possible by sending scancode bus events of type keyboard-code to the keyboard bus V86.keyboard_adapter.bus. A scancode is an integer representing the location of a key on a keyboard.

If you only want to send non-alphanumeric keys (Shift, Ctrl, Alt, ESC, F1-F12, etc.) then it's straight forward, because these keys have fixed scancodes (locations) on all keyboards from all countries for decades (unlike the alpanumeric keys like "A", "B", etc.).

To find the scancode of a specific key, first see here and here for the KeyboardEvent.code values of the non-alphanumeric keys.

Then see here here for code that maps between KeyboardEvent.code (string) and keyboard-scancode (16-bit integer) values.

Note that in order to inject a full keystroke into V86, you have to send two bus events, one for key-press and another for key-release. The scancode for release is the same as for press but with the most significant bit (0x80) set to 1.

Most scancodes are 8 bit, but if a scancode has 16 bits you first send the most significant 8 bit to the bus, then the least significant 8.

I've put it all together in Internationalizing Copy and Paste, you should find all you need in my code (specifically keyboard_lib.js, at the bottom I've already prototyped the function you're looking for see function ev_codes_to_scancodes() for code that does what you want) and comments there.

EDIT: Fixed outdated infos.

[chschnell]

I came around and implemented the KeyboardEvent.code => scancode mapping you'd need.

In keyboard_lib.js you find a single class VirtualKeyboard, here is how to use it to inject non-alphanumeric keystrokes into V86.

For example, let's say you have a running V86 instance emulator and you want to inject keystrokes Ctrl+Alt+Del:

const scancodes = VirtualKeyboard.ev_codes_to_scancodes(["ControlLeft", "AltLeft", "Delete"]);
VirtualKeyboard.paste_scancodes(emulator, scancodes);

It will send the following sequence of key events to emulator:

<Ctrl-Down> <Alt-Down> <Del-Down> <Del-Up> <Alt-Up> <Ctrl-Up>

Or the same represented in 16-bit scancodes:

1D 38 E053 E0D3 B8 9D

It's tested and works. Note that it's not constrained to non-alphanumerics, this would also work:

const scancodes = VirtualKeyboard.ev_codes_to_scancodes(["ControlLeft", "AltLeft", "KeyA"]);
VirtualKeyboard.paste_scancodes(emulator, scancodes);

But you cannot inject continuous text like "Hello, world!" this way. Here's how you'd send continuous text using a US-keyboard layout:

const keyboard = new VirtualKeyboard("kbdus");
const scancodes = keyboard.text_to_scancodes("Hello, world!");
VirtualKeyboard.paste_scancodes(emulator, scancodes);

So it's basically a virtual PC keyboard class for V86.

[FunnyCorgi]

@chschnell

but with the most significant bit (0x80) set to 1.

What do you mean by this?

[SuperMaxusa]

In one sentence: the PS/2 controller registers the key hold until you send a scancode(s) to release the key(s).

v86/src/browser/main.js

Lines 2239 to 2250 in f92e6b4

	emulator.keyboard_send_scancodes([
	0x38, // alt
	0x0F, // tab
	]);
	setTimeout(function()
	{
	emulator.keyboard_send_scancodes([
	0x38 | 0x80,
	0x0F | 0x80,
	]);
	}, 100);

https://www.eecg.utoronto.ca/~pc/courses/241/DE1_SoC_cores/ps2/ps2.html#id478856

[FunnyCorgi]

OK, so basically I'm just supposed to bitwise OR. Got it.