simple keyboard event handler in D - linux

I am trying to make a simple keypress handler that I can recycle into any program I'd like to make in D. In my search I can only really find information on how to do this in C, namely by using getch() to read characters from the command line input buffer. But I don't neccessarily want to run a program on the command line. Much like every other program in existence. I've been looking everywhere for this, even on Dlang.org , and haven't found a satisfactory answer yet.
In my specific case I'm trying to make a simple game as a project to help me learn D and I realized that I needed keypress handling so I could, at the very least, navigate menus I'd create in a more natural way so I could properly test my game.
I would eventually like this system to be usable on both windows and linux interchangably, probably just by detecting the operating system the program is running on at launch and then choosing the right code to run to make it all work. But that will come later. Right now i just want to know how to build a simple Keypress event handler that can trigger a function or method or whatever I want as soon as I press the key and have it work in a windows environment.

Related

How does the Ctrl + Z keyboard shortcut actually work in general?

I mean, its not about some code or something, but how does that shortcut work in general, like when I am working on a something and accidentally, I delete a chunk of text, how does the shortcut, revert it back on to the screen, don't give me the code or something, but take instances of elements in the coding world like whiles, ifs etc. How did the creator get the idea that something like this should even exist?
There are multiple ways this can be achieved, the decision how, is up to the developer to decide.
One way is to make use of a stack, where the where the state of this program is stored in such a structure.
Another way is use a design pattern called the command pattern which is often used to implement undo redo functionality, this is very similar to a stack, but instead of storing the program state, you save the action done to the program together with a similar action to undo the executed one.

Sending keystrokes to an unfocused process pywinauto

I'm trying to send keystrokes of regular keyboard input from 'a-z' which may or may not include the directional arrow keys to a running game process, however i'm confused at the pywinauto documentation:
I've already connected the existing process via pid by:
from pywinauto.application import Application
from pywinauto.keyboard import SendKeys
app = Application().connect(process=1234)
#app.SendKeys('a')? Doesn't seem to work
I've read some other answers on this but it's not very clear as to what the next step is on the documentation, there aren't any real examples.
I've also read from some other answers that SendKeys auto focuses the windows, which isn't want I want, if possible would it be possible to send keystrokes to the process silently?
There are few moments. If the game process has its own window with native handle, you may try the following:
app.window(title="Window title").send_keystrokes("something")
app.window(title="Window title").send_chars("something")
It should work even for minimized window. The difference may appear for special symbols which may not work for some of these methods or even for both. But arrows should probably work with send_keystrokes.
If it's DirectX game, sending keys might be more complicated task. A while ago I found some references about potential implementation of this: https://github.com/pywinauto/pywinauto/issues/469 Though I had no chance to try it yet.

Computer keyboard into piano keyboard with AutoHotkey

I want to be able to use my computer keyboard as a piano keyboard, however the default version of AutoHotkey only supports one "voice" at a time. I tried running an instance for each note, but that doesn't fix it if I press the same note repeatedly.
I found this thread on how this might be solved with the BASS library, but I'm pretty green when it comes to coding and so I'm not certain how to incorporate the library into my simple code.
Here's another similar forum that might solve things, but it has a delay and the overlapping solution doesn't really solve my issue.
This is such a simple idea (play sound when a button is pressed), but somehow it's way out of my depth. Currently my code looks like this:
~1::
SoundPlay, C:\Users\Fires\Downloads\2489__jobro__piano-ff\39187__jobro__piano-ff-040.wav
for each note
Edit:
~a::
FileDelete, %A_ScriptDIR%\Sound1.AHK
FileAppend,
(
SoundPlay, C:\Users\Fires\Desktop\New folder (4)\043.wav, Wait
), %A_ScriptDir%\Sound1.AHK
Run, %A_ScriptDIR%\Sound1.AHK
Return
is what I am using now, but it's still iffy when two are pressed at the same time.
Its likely due to the "Wait". according to the documentation:
https://autohotkey.com/docs/commands/SoundPlay.htm
"If a file is playing and the current script plays a second file, the first file will be stopped so that the second one can play. On some systems, certain file types might stop playing even when an entirely separate script plays a new file."
It looks like this is an "issue" with AutoHotKey. And its not possible to open multiple "voices" or simultaneous sounds. it is completely possible to make a C# program that does the same thing, I've done it before. and i have bits of the code now still (it plays midi sounds, instead of wavs, but same concept play notes asynchronously).

Open a new window for a milisecond in python(3x)

I'm making a small game where you have to guess if the answer is cp1 or cp2 and I want to give the user some sort of hint. One way of doing that I think is by flashing the answer for a nano or milisecond to user, i.e. a new window would open with a : . Any ideas as to how to do this?
[...] flashing the answer for a nano or millisecond to user [....] in a new window [...]
A millisecond is too short (both for the human player -read about the persistence of vision- and for the Python interpreter); your screen is probably refreshed at 60Hz. Consider flashing for at least one tenth of a second (and probably more than that, you'll need to experiment, and you might make the flashing delay or period configurable). How to do that depends upon the widget toolkit you are using.
If using something above GTK, you'll need to find the Python binding to g_timeout_add, see also this.
If you use something above libSDL (e.g. pygame_sdl2), you need something related to its timers.
There are many other widgets or graphical frameworks usable from Python, and you need to choose one (look also into PyQt). Each of them has its own way to deal with timing, delays, windows, graphical display of text inside a window, etc...
If your system is Linux, see also time(7) for a general overview of time related things. Event loops (like those in graphics libraries) are built above a multiplexing system call such as poll(2) (or the old select, etc...).
You need to spend several days in reading more, choosing your graphical toolkit, before coding a single line of code of your game (which might need more code than what you imagine now).
I think the closest you can easily get to this affect is to just print to the console, but don't print the new-line (\n), just the carriage return (\r). This way you can write over the text after a couple of milliseconds. We do need to know the length of the thing we are printing so that we can be sure to completely override it with the next print.
The code for this would look something like:
import time
ms = 100
s = 'cp1'
print(s, end='\r')
time.sleep(ms / 1000)
print(' ' * len(s))

How can I change Linux terminal to make it look like the command "top"?

My aim is to make a program using C or C++ that prints to the Linux console in a similar way "top" does, in the sense that top's content updates and changes the existing text in the console, rather than printing new lines. How? I only want to know what are the syscalls or functions that make this possible. A little example would be very much appreciated.

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