Get text around input caret on Linux - linux

Motivation: I'm trying to write scripts which send keystrokes to the currently focused window. Right now I use xdotool, which lets me send raw keystrokes. However, I want the exact keystrokes to be a function of the current text around the input caret in the focused window.
Problem: Is there a generic way of reading the state of the text input caret -- both its current position as well as the text around it? Intuitively, I want the content of the current "text box" as well as the location of the cursor within that text box. Perhaps this is not possible in the general case, but is there a way of doing it which would work for emacs and firefox? I'm running Ubuntu Linux
Further motivation: due to a bad case of RSI I control my computer by voice rather than typing. This works by setting up voice-activated scripts that are triggered by saying different phrases. When dictating English prose, it would be helpful to automatically capitalize words at the beginning of sentences. This automatic capitalization can be accomplished by reading the characters immediately before the input caret, checking if they contain a period, and if so, capitalizing the start of the next phrase that I dictate by voice.
Thanks so much! If anybody can help me here, it would greatly increase my day-to-day accessibility.

Since there is no standard widget toolkit for X11, but only a buch of independently developed arbitrary toolkits, there is no generic way to implement this.
As far as X11 and tools operating on its level (like xdotool) is concerned, there's only windows of either the InputOutput variety (i.e. visible windows, that receive events and one can draw to) or the just Input which are invisible and only receive events. There are no further refined "widgets" so to speak. You get a pixel grid, which you can draw to.
Accessibility interfaces are the burden of the toolkits (or if you don't use a toolkit – then you're a badass – you, the developer), to implement: https://www.freedesktop.org/wiki/Accessibility/
The absolute generic way would be to take a screenshot of the currently focused window, employ a computer vision / machine learning based solution to identify the caret, then OCR the line of text around it. And to be honest, IMHO doing it that way would probably be a lot more reliable than hoping for the accessibility interfaces to be properly implemented.

Related

How to change the color values of the operating system

I'm doing research about a schoolproject. The project is to develop a program that can change the colors of the screen (of the OS aswell of all programs that run on it). The endproduct is supposed to be a single program that is able to change the colors by input (i.e. increasing the presentness of a primary color, for instance add 10% RED), and is an experimental approach to manipulating color blindness. I've already done the theoretical biological research, now I'm looking into the practical deployment of such an application.
I have not set on a single programming language, as I do not know which ones would be the best for, let's say, the windows 7 environment. (which language features the easiest/fastest function calls, for example)
Some examples of function calls I intend to program:
GetColorValues (return data about the current colors the pixels of the screen are displaying)
ProcessColorValues (A simple modification of all respective colors returned by the function above)
SetColorValues (Return the modified colors back to their respective places on the screen)
I would prefer being able to intercept the data whilst it is being pipelined to the screen, in order to keep the processing smooth.
Technically now, I don't really know where to start. I don't even know if I'm supposed to look into the OS, or the drivers of the graphics card.
I was hoping someone could guide me and tell me what I should look for, or where I could find these.
Thanks for reading.
Arnaud
The Windows Monitor Configuration Functions could be a starting point - for example the SetMonitorRedGreenOrBlueGain function to boost specific colors. You should be able to call these functions from C# or VB.Net using PInvoke

Shell formatting language

On linux, console applications have the ability to format their output. They can set font color, set background color and can place signs everywehre on the console. Using that it is, for example, possible to implement a tetris game right into the console.
I´m wondering how one can do that. I think they use a output markup language or something else. Can anyone tell me where I can learn more about this?
Thanks very much!
Most console applications involving a lot of motion or color are built using the ncurses library. Some very common examples would be irssi (IRC client), mc (Midnight Commander, the console file browser), mutt (POP3/IMAP mail client)
It seems like you are already aware of the escape codes used to modify console colors. A good list of console color escape sequences (for Bash) can be found here.
You obviously need to get a hold of those every-popular Unix video games, rogue, srogue, larn, hack, and/or nethack. They have a long and venerable history.
Notably, these all use the standard curses — or more recently, ncurses — library. Here’s a screen shot.
Since they have no joystick, motion is with vi commands. They are hands-down the very best way to hone your vi motion skills ever invented: no more two-finger typing for you! You stop thinking about motion; it just becomes a part of your fingers’ muscle memory. You really have to play them to get a feel for the awesome “Zen” state you can get into playing them:
After enough practice, it feels as though your fingers themselves remember how to play the piece. You don’t even watch them. They've a job to do, and once they’ve learned it, can go about that job remarkably free of direct supervision. The key to clearing the mind of the outside world, so that the program becomes the dominant reality, is what a musician would call “finger memory”. (You might have heard athletes or dancers refer to it as muscle memory, but when we’re talking about using the computer, it really is the fingers that count.)
[...] Of course, that's not really what’s going on; it only seems to be. Your fingers don’t really remember. But a part of your brain that controls them does, even though “you” don’t realize it. What’s happened is that you've so successfully assimilated the moves needed that conscious direction is no longer required. The little lighthouse keeper behind your forehead can worry about other things, assured that your fingers will do the job you’ve trained them to do. Your eyes are on the screen, the program in your head, and your head is in the program. Your fingers become an unnoticed extension of your will. [...]
[...] There’s no question that, for certain tasks, the keyboard is clearly the optimally efficient input device. Consider the game of rogue or one of its more recent incarnations. You wouldn’t want to use anything but a keyboard there. The command set is just too rich. Trying to play the game with a mouse‐and‐menu interface instead of a keyboard one would slow you down by at least two orders of magnitude.
The rogue family of video games are also notable for showing how to write a video game for a regular terminal like a vt100 or an xterm, which I believe is what you are looking for. I’d probably use a more modern language than C these days, but all the same principles still apply. Both Perl and Python have good interfaces to these standard libraries.
It's not so much a markup language as a series of escape sequences that trigger the terminal viewer to format in a certain way.
You can send ANSI escape sequences before your output to indicate that the following output should be a certain color, weight, background. You can also send sequences that jump the cursor to specific locations to continue writing output.
If you are going to do a full blown app you should consider using some library such as ncurses which makes these manageable.

Using a piano keyboard as a computer keyboard [closed]

Closed. This question is off-topic. It is not currently accepting answers.
Closed 9 years ago.
Locked. This question and its answers are locked because the question is off-topic but has historical significance. It is not currently accepting new answers or interactions.
I have RSI problems and have tried 30 different computer keyboards which all caused me pain. Playing piano does not cause me pain. I have played piano for around 20 years without any pain issues. I would like to know if there is a way to capture MIDI from a MIDI keyboard and output keyboard strokes. I know nothing at all about MIDI but I would like some guidance on how to convert this signal into a keystroke.
I haven't done any MIDI programming in years, but your fundamental idea is very sound (no pun).
MIDI is a stream of "events" (or "messages"), two of the most fundamental being "note on" and "note off" which carry with them the note number (0 = C five octaves below middle C, through 127 = G five octaves above the G above middle C, in semi-tones). These events carry a "velocity" number on keyboards that are velocity sensitive ("touch sensitive"), with a force of (you guessed it) between 0 and 127.
Between velocity, chording, and the pedals, I'd think you could come up with quite a good "typing" interface for the piano keyboard. Chording in particular could be a very powerful technique — as I mentioned in the comments, it's why rank-and-file stenographers can use a stenotype machine to keep up with people talking for hours in a row, when even top-flight typists wouldn't be able to for any length of time via normal typewriter-style keyboards. As with machine stenography, you'd need a "dictionary" of the meanings of chords and sequences of chords. (Can you tell I used to work in the software side of machine stenography?)
To do this, the fundamental pieces are:
Receiving MIDI input. Don't try to do this yourself, use a library. Edit: Apparently, the Java Sound API supports MIDI, including receiving events from MIDI controllers. Cool. This page may also be useful.
Converting that data into the keystrokes you want to send, e.g. via the dictionary I mentioned above.
Outputting the keystrokes to the computer.
To be most broadly-compatible with software, you'd have to write this as a keyboard device driver. This is a plug-in to the operating system that serves as a source for keyboard events, talking to the underlying hardware (in your case, the piano keyboard). For Windows and Linux, you're probably going to want to use C for that.
However, since you're just generating keystrokes (not trying to intercept them, which I was trying to do years ago), you may be able to use whatever features the operating system has for sending artificial keystrokes. Windows has an interface for doing that (probably several, the one I'm thinking of is SendInput but I know there's some "journal" interface that does something similar), and I'm sure other operating systems do as well. That may well be sufficient for your purposes — it's where I'd start, because the device driver route is going to be awkward and you'd probably have to use a different language for it than Java. (I'm a big fan of Java, but the interfaces that operating systems use to talk to device drivers tend to be more easily consumed via C and similar.)
Update: More about the "dictionary" of chords to keystrokes:
Basically, the dictionary is a trie (thanks, #Adam) that we search with longest-prefix matching. Details:
In machine stenography, the stenographer writes by pressing multiple keys on the stenotype machine at the same time, then releasing them all. They call this a "stroke" of the keyboard; it's like playing a chord on the piano. Strokes frequently (but not always) correspond to a syllable of spoken language. Like syllables, sometimes one stroke (chord) has meaning all on its own, other times it only has meaning combined with following strokes. (Think "good" vs. "good" followed by "bye"). Although they'll be heavily influenced by the school at which they studied, each stenographer will have their own "dictionary" of what strokes they use to mean what, a dictionary they will continuously hone over the course of their working lives. The dictionary will have entries where the stenographic part ("steno", for short) is one stroke long, or multiple strokes long. Frequently, there will be several entries with the same starting stroke which are differentiated by their length and by the subsequent strokes. For instance (and I won't use real steno here, just placeholders), there may be these entries:
A = alpha
A/B = alphabet
A/B/C = alphabetic
A/C = air conditioning
B = bee
B/C = because
C = sea
D = dog
D/D = Dee Dee
(Those letters aren't meant to be musical notes, just abstract markers.)
Note that A starts multiple entries, and also note that how you translate a C stroke depends on whether you've previously seen an A, a B, or you're starting fresh.
Also note that (although not shown in the very small sample above), there may be multiple ways to "play" the same word or phrase, rather than just one. Stenographers do that to make it easier to flow from a preceding word to the next depending on hand position. There's an obvious analogy to music there, and you could use that to make your typing flow more akin to playing music, in order to both prevent this from negatively affecting your piano playing and to maximize the likelihood of this actually helping with the RSI.
When translating steno into standard text, again we use a "longest-prefix match" search: The translation algorithm starts with the first stroke ever written, and looks for entries starting with that stroke. If there is only one entry, and it's one stroke long, then we can reliably say "that's the entry to use", output the corresponding text, and then start fresh with the next stroke. But more likely, that stroke starts multiple entries of varying lengths. So we look at the next stroke and see if there are entries that start with those two strokes in order; and so on until we get a match.
So with the dictionary above, suppose we saw this sequence:
A C B B C A B C A B D
Here's how we'd translate it:
A is the start of three entries of varying lengths; look at next stroke: C
A/C matches only one entry; output "air conditioning" and start fresh with next stroke: B
B starts two entries; look at next stroke: B
B/B doesn't start anything; take the longest previous match (B) and output that ("bee")
Having output B = "bee", we still have a B stroke in our buffer. It starts two entries, so look at the next stroke: C
B/C matches one entry; output "because" and start fresh with the next stroke: A
A starts three entries; look at the next stroke: B
A/B starts two entries; look at the next stroke: C
A/B/C only matches one entry; output "alphabetic" and start fresh with the next stroke: A
A starts three entries; look at next stroke: B
A/B starts two entries; look at next stroke: D
A/B/D doesn't match anything, so take the longest previous match (A/B) and use it to output "alphabet". That leaves us with D still in the buffer.
D starts two entries, so we would normally look at the next stroke — but we've processed all the strokes, so consider it in isolation. In isolation, it translates as "dog" so output that.
Aspects of the above to note:
You have a buffer of strokes you've read but haven't translated yet.
You always want to match the most strokes against a single entry that you can. A/B should be translated as "alphabet", not "alpha" and "bee".
(Not shown above) You may well have sequences of strokes that you can't translate, because they don't match anything in the dictionary. (Steno people use the noun "untranslate" -- e.g., with our dictionary, the strokes E would be an "untranslate".)
(Not shown above) Some theories of steno allow the same set of strokes to mean more than one thing, based on a broader context. Steno people call these "conflicts". You probably want to disallow them in your project, and in fact when steno used to be translated manually by the stenographer, conflicts were fine because they'd know just by where in the sentence they were what the right choice was, but with the rise of machine translation, conflict-free theories of steno arose specifically to avoid having to go through the resulting translated text and "fix" conflicts.
Translating in real time (which you'd be doing) means that if you receive a partial match, you'll want to hold onto it while waiting for the next chord — but probably only up to a timeout, at which point you'd translate what you have in the buffer as best you can. (Or maybe you don't want a timeout; it's your call.)
Probably best to have a stroke that says "disregard the previous stroke"
Probably best to have a stroke that says "completely clear the buffer without outputting anything"
Consider doing something in hardware that emulates a usb (or ps/2?) keyboard. You will no longer be dependent on a specific OS, or specific OS API. A hardware solution will stand the test of time. Don't be stuck using an old API in Windows 7 when everyone else is running Windows 11! Arduino is pretty easy to learn.
Arduino MIDI hardware is available off of the shelf
Arduinos have been used to emulate keyboard devices
There is a ton of info and help out there for Arduino. It is a hardware hacking platform built for newbies. It will only get bigger now that Google is pushing Arduino.
EDIT: Virtual USB Keyboard software and hardware
It sounds to me like you're looking less for advice on how to build this yourself and more asking what resources are already out there to accomplish what you want. Depending on your OS, there are many ways to accomplish this without having to write your own program from scratch:
MIDI Stroke
Free. For Mac OS X 10.3 and up. This one specifically comes with "the ability to use any MIDI keyboard as a full blown computer keyboard replacement."
Bome's MIDI Translator
Free/Postcardware (it's a bit odd). For Windows 2000 and up, and Mac OS X. It initially appears to be more geared towards AutoHotkey-type usage, but on further looking I think it could do what you want nicely.
Max and aka.keyboard
Free. For Mac OS X. Not exactly a "ready out of the box" solution, but if you are comfortable with basic device configuration, it shouldn't be too bad.
You can access the hardware with source code samples in .NET in MIDI DotNet.
A complete working sample as sourcecode to create MIDI notes data stream is in VB 5/6-Tipp 0521: MIDI-Töne erzeugen (Visual Basic 6.0, somewhere is .NET version too)
A way to simulate keyboard strokes is in VB 5/6-Tipp 0155: Tastaturereignisse simulieren (Visual Basic 6.0, somewhere is .NET version too)
And recognize keystrokes is describedin Tipp-Upload: VB.NET 0266: Globaler KeyHook.
Then, just use a good working matrix for a piano player
On piano and when you're a good player, you can have 10 fingers on the keyboard and if the matrix is usable you can be much more quickly that any computer keyboard user I think. :-)
In that case, if I understand your question right, it should not be a big thing.
I studied piano performance in college and then got into interaction design, programming, and using Vim, so I have actually spent a lot of time prototyping things like this.
You can get this working pretty quick in Linux by using the graphical programming language for multimedia artists, "Pure Data," along with the x11key external by Alex Andre.
On Mac, you can use MidiStroke. I believe a method on Windows involved the MidiOx and AutoHotKey tools. At another time I had a version going using the Java plugin for Max/MSP. I believe Patrice Colet made a windows external for Pure Data that worked as well, but I can't seem to locate it anymore. Also, there's an external for MaxMSP that can do this on Windows. Finally, the non-free but awesome Osculator can do what you want - see the features page.
When I got it working, I never stuck with it, because I couldn't stop tooling with the layout. It was cool just having my monitor on my electric keyboard, though! Good luck.
About MIDI
You stated that you "know nothing at all about MIDI". MIDI technology is fairly straight-forward once you grasp it, but it can be confusing at the outset. One of the resources that has been tremendously helpful for me in understanding the foundations for MIDI (which are certainly necessary if you want to program MIDI interactions), is a book called MIDI for the Technophobe. It's an easy book to read and is very helpful.
Pure Data & Max
In my experience developing interactive multimedia, there are two very similar programs I have encountered that facilitate connecting and mapping signals/inputs from any device.
These are Max for a Mac environment and Pure Data for a PC environment. Both have a plethora of online documentation and YouTube tutorials. The video Max/MSP Tutorial 1 - using your computer keyboard as midikeyboard (ableton style) demonstrates a program built in Max that maps a computer keyboard to a MIDI keyboard's inputs (which is basically the exact opposite of what you are trying to do). You could get your intended results by using the same pattern, but reversing the signals/mappings.
AutoHotKey
AutoHotKey is a free open source utility for Windows that allows you to remap keys and buttons on your devices to macros. It natively supports QWERTY keyboards, joysticks and mouse macros.
However, I was able to find an implementation supporting the specific mapping you are looking for. These two threads explain the process:
MIDI IN support in AutoHotkey , the discussion of the use case. The author was looking for a program that could detect MIDI IN input and translate that to keypresses.
MIDI input library , the solution to the author's problem and the posted code/patch to AutoHotKey which actually implements your intended result.
Basically, it looks like AutoHotKey, along with this user's custom patch, will provide exactly what you need to create a mapping from a MIDI keyboard to a QWERTY keyboard's input signal. All you would have to do is install, configure and define your mappings.
Anything else?
Some of the other answers have given you much more extensive information on MIDI and MIDI programming, in general, but as your post states that doesn't seem to be quite what you are looking for. I would like to help you more if possible, but it would be easier if you could be more specific about the type of information you are looking for. For instance, are you more interested in how to convert a MIDI keyboard's input signals to a QWERTY keyboard's signals, or is your primary interest finding an out of the box solution to your specific problem? What are you looking for that has not yet been addressed?
You could hack your own USB keyboard pretty quickly using a Teenys micro controller.
In fact, they have example code for how to make a USB keyboard.
You could approach this two ways:
Get an old piano and wire up switches directly to the teensy
Add the additional logic to connect to the MIDI port and necessary decoding.
Actually, I worked on this a while ago, trying to capture Rock Band drum inputs into my computer (making a little Java homemade drum emulator) Anyway, I asked a question on here about that, Time delay problem (there is polling code in there, along with what I was attempting to do.). And if I can find my program I can give you the code, it uses a third-party API (JInput).
Good luck either way.
Try Bome's MIDI translator.
It works cross platform, can convert any MIDI input to a keystoke easily, quick to setup and configure, plus it's free for personal use.
There is a tutorial, Quick Tip: MIDI Translation – MIDI to Keystrokes, of how to easily set it up:
Basically, there are infinite possibilities of what you can do, including chording and modifier keys. I use it for my live audio rig to control my DAW using my piano and have never had an issue.
In Java, you can use JMF (Java Media framework) to convert MIDI signals.
Basic of keyboard design is easy to use, that is, the user interface; and place frequently used charcter/symbol handy.
The sample code and API in Java Sound Resources: Examples: Digital Signal Processing (DSP) help to understand how to process the signal.
Some more references:
Processing Audio with Controls
Digital Audio Signal Processing, 2nd Edition
A good library in .NET with full midi support (BASS), go to http://www.un4seen.com.
And for the other part, translating keyboard midi notes to keys and more, I would go for AutoItX, the ActiveX/COM and DLL interface to autoIt. Info and download, go to http://www.autoitscript.com/site/autoit/
No need to write keyboard driver.
There is a program called GlovePIE. You can program it in a simple scripting language, and I believe it supports MIDI. I'm not sure if this fits under the "Java" category, but still, it is a great program. I've used it to control robots using PS3 controllers. It's very powerful.
Many keyboards have a serial port (RS-232) connector to send MIDI signals to the computer. I use a program called Girder to convert serial port communication into keyboard strokes.
Girder has a "mapping" feature that lets you map each key, one by one, to the corresponding keystroke.
This might be the simple solution you're looking for!
Just learn stenography!
It's clear from all the discussion on your part. You don't want to re-invent any wheels, from a technical standpoint. But once you have a connection made (what this question is asking) and up and working, you still have most of the work ahead of you: You have to train your brain. You also have to invent the cleverest, most efficient way to do that - a design issue totally out of the rhealm of computer techies. You or any of us would fall short.
Fortunately, the problem has been solved and honed though centuries of maturing...
Learn stenography!
Yes, this will set you back some jack. But what are hundreds of hours of your own time worth, with at the end, a less favorable result? Besides, the stenography Wikipedia article says, 'it looks more like a piano keyboard'.
Unless, of course, you want to have a sideshow effect going. I would have to admit, I never thought of this possibility, it it would be really entertaining to see somebody bust out a text from a piano keyboard!
You could start with a USB keyboard with touchpad (or a pointing stick would be more ergonomic?), use Plover to translate it (I'm sure it can be configured to let the non-letter keys retain their functionality as they are critical for programming), or, follow the thread Re: Plover keyboard to roll your own USB stenography keyboard, or, buy a stenotype.
Good luck!
Take a look at MAME arcade gaming. They have built hardware devices to allow input from any number of different items. The iPac, for example, converts signals from input devices into USB that the computer can then use to emulate keys. You could use any combination of input devices arranged any way that seems comfortable with no crazy programming logic required--because the software to interpret input is already done and well tested.
I've seen flight simulator cockpit inputs, custom kiosks, and voting systems built in this method.....and the price is right!
To solve this you will need a few things:
A way to capture MIDI data from your keyboard. Depending upon the interface: MIDI interface (classic) or USB MIDI interface (modern) the most likely interface is to a computer as it provides the most options. USB host microcontrollers are not as simple as just using a computer.
A scheme to convert MIDI data into keystrokes. Like one user pointed out, chords are the way to go as the number of keys will not be dependent upon the number of piano keys.
A way to inject a key into the operating system. This will require a low-level driver to be accurate. I have played around with applications that inject keyboard and mouse data into applications in Windows 7, and it can be flaky and depend upon whether an application is currently in focus. This is hardest part of the interface. What may work is to create a HID USB keyboard microcontroller that also has a serial interface.
The serial interface would create a virtual serial port. The software that reads the MIDI data and produces the keystrokes could send a serial message to the virtual serial port. The microcontroller would send a keystroke so it would look like a standard keyboard input. This would allow interfacing both MIDI ports and USB MIDI keyboards.
Hmmm, with this type of interface you could also simulate a mouse and use some piano keys setup for the mouse axis and buttons. The pressure could be used to determine mouse pointer velocity. So you could eliminate the mouse as well. Another benefit of this approach is any type of input device you connect could talk to the virtual serial port to produce keyboard and mouse events. So if you wanted to add other hardware such as drum pedals or a joystick it would be a matter of adjusting the program that talks to the serial interface.
Another take on the above is like some posted above to use an Arduino, but also include USB Host Shield from Sparkfun to handle USB based music keyboards. This allows the Arduino to be programmed as a keyboard or keyboard mouse combo in the boot loader chip and allows the device to act a USB host for the USB based music keyboard. Then you are covered for both types. Although, I still think the virtual serial port method is more flexible and would be easier to program in the long run. The Arduino device will be harder to change than a desktop program or service.
There is another possibility:
Chorded one handed keyboards already exist. I have seen videos on them, but you would have to determine if those hurt your hands or not.
It should be fairly easy using something like the .NET DirectSound interface to hook into an MIDI device. You will need to identify your target MIDI device and then get the code to listen in on the incoming messages (there are articles about doing this via Google).
Since you are using the MIDI in as a keyboard there are basically only two MIDI messages that you need to detect, namely note on and note off. The MIDI message is three data bytes specifying the command, the note and the velocity. The note off is just the note number (sometimes 'bad' MIDI stacks send a note on with zero velocity which you also have to expect).
Once you have the messages translating them the keyboard output should be fairly simple from .NET.
There is plenty of advice in the other answers about the technicalities; I just wanted to give you an idea of the actual MIDI messages. Good luck!
You'll get better and happier results (regardless what operating system and/or DAW program you like to use) by playing any external MIDI keyboard as a controller through your sound card. Then route that into your GB software (or whatever) and tone generate the many sounds they have supplied you that way in real-time.
If your sound card does not support MIDI I/O's (ins / outs /thrus), that's not a problem. You can consider researching and investing in an external MIDI table top converter. Many are equipped to further convert MIDI outs to USB 2.0 (by- passing an existing sound card altogether).
For example: it's pretty tough getting "human like" grace note results via a Z and X change key option using a computer keyboard and pencil tool. When, instead, your own fingers can just play that with a MIDI keyboard from its own physical octave register ranges—immediately!
I realize budgetary constraints may be involved. But, some of these seemingly cheap "Casio" type 5 octave keyboards sold at Radio Shack for under $100.00 U.S. Dollars (*or less) is all you would need (plus, some of their on-board sound patches and sequencer modules sound and handle amazingly well for other things too).
RadioShack MIDI keyboard options.
As for external MIDI converters for existing sound cards, I've run some Google searches for you as follows with Mac platforms specifically in mind:
A lot of this external MIDI conversion information may be cumbersome to you at first, so I've broken down things more as "user friendly" for your considerations & budget:
MIDI sound cards
There's nothing wrong with facilitating virtual keyboards as VST's when using DAW. They have their place.
But, you sound like an accomplished keyboardist. So, why not consider the external MIDI conversion / keyboard options I just mentioned for yourself?
Good luck and I hope this gave you some ideas that can and will work for you!
If you don't want to do any programming yourself but just want the problem solved you can just buy a USB-MIDI-keyboard where you can re-assign any key to send a QWERTY keyboard output signal instead of a MIDI-output, for example M-Audio Axiom Pro
This method will work with any OS and any computer that supports standard USB-keyboards since the MIDI-keyboard will identify itself as a standard QWERTY keyboard.
You can use a simple AutoIt script to both read MIDI events, see MIDI Input.
You'll also need MIDI UDF and simulate key presses.
Reading MIDI events should be easy, but different MIDI controllers (instruments) have different features. Try to find out what your MIDI piano can do first, then see how you can best map those features to simulated QWERTY-keyboard presses.
If you want, you could have something on screen or in the tray to help you see what you are doing (that is, for Shift, Ctrl and Alt simulation).
You might take a look at chorded keyboards. They have the advantage that you don't need to write a driver for them before you can use them, and some are similar to the layout of a piano keyboard.
If you know coding in Java, you could use this way:
First, implement a javax.sound.midi.Receiver with a send(..) method that is mapping the 'Note on' events to keystrokes like you want.
You would need to get the MidiMessage's content with its getMessage method and intepret it in your fashion. The meaning of the message bytes can be found in MIDI Messages.
After receiving a 'note on' or 'note off' for a certain keyboard key, you may map that to a key you like by assigning it a constant of the KeyEvent class, something like C#4 -> KeyEvent.VK_A and so on. This key code can then be used by java.awt.Robot's keyPress and keyRelease methods to actually send the keystroke to the OS and thus to other applications.
I agree with Brian O'Dell's answer - if this were my project, I'd do it in hardware. It has the advantage of being platform and hardware independent - your box replaces the need for a MIDI-USB interface and a PC API.
mbed is a fast-prototyping platform that is very easy to learn, and has multiple advantages over Arduino IMHO (online compiler, 512 KB flash, 96 MHz, C++ language). It has a USB keyboard interface and a USB Midi interface pre-written for you.
The community is very friendly and willing to help, and there are a lot of existing projects using both MIDI and USB hid emulation - search Youtube for "mbed MIDI" or similar.
If you use Linux have a take at Footware.
It should be exactly what you're looking for - if you adjust the MIDI pitches to a keymapping of your liking...
I never thought this could be useful for anyone but me ;o)
Try using a microcontroller-based system, like Arduino.
This wouldn't be too tough.
I'm assuming you're on Windows, not sure about that though. I've written a MIDI sequencer, http://pianocheetah.com, in plain old C++, and it lets you use the piano keyboard to run commands. There isn't any reason you couldn't do the same thing to push keys
into the keyboard input stream.
But come on now. You remember how long it took you to learn
the keyboard in the first place, right?
Are you willing to go through that again?
And are you willing to pollute your blessed keyboard with
a bunch of stupid looking key symbols all over it?
You'll need to use at least 26 alpha, 10 numeric, 11 punctuation,
and at least 12 function keys AND their shifted states.
So that's 60 keys plus shifted states.
That'll burn up a full 5 octaves of keys.
You will be doing piano "hops" =all= the time.
Say goodbye to touch typing.
You may save yourself from RSI, but you've created another
different type of nightmare for yourself.
And good luck getting your boss to buy you a MIDI keyboard at work.
If you've learned to truly play piano, you've learned
how to play stress free. Do that on the QWERTY keyboard.
No tension. Start slow.

Colour blindness simulator

Like any responsible developer, I'd like to make sure that the sites I produce are accessible to the widest possible audience, and that includes the significant fraction of the population with some form of colour blindness.
There are many websites which offer to filter a URL you feed it, either by rendering a picture or by filtering all content. However, both approaches seem to fail when rendering even moderately complex layouts, so I'd be interested in finding a client-side approach.
The ideal solution would be a system filter over the whole screen that can be used to test any program. The next best thing would be a browser plugin.
I came across Color Oracle and thought it might help. Here is the short description:
Color Oracle is a colorblindness simulator for Windows, Mac and Linux. It takes the guesswork out of designing for color blindness by showing you in real time what people with common color vision impairments will see.
Color Oracle is great, but another option is KMag, which is part of KDE in Linux. It's ostensibly a screen magnifier, but can simulate protanopia, deuteranopia, tritanopia and achromatopsia.
It differs from Color Oracle by requiring an additional window in which to display the re-coloured image, but an advantage is that one can modify the underlying image at the same time as previewing the simulation.
Here is a screenshot showing the original figure on the left, and the KMag window on the right, simulating protanopia.
Here's a link to a website that simulates various kinds of color blindness:
http://www.vischeck.com/
They let you check URL's and Screenshots with three kinds of different color blindness types (URL checking is a bit dated though. Image-check works better).
I'd encourage everyone to check their applications btw. Seeing your own app with others eyes may be an eye opener (pun intended).
I know this is a quite old question, but I've recently found an interesting solution to transparently simulate color blindness.
When working with Linux, you can simulate color blindness using the Color Filter plugin for Compiz. It comes with profiles for deuteranopia and protonopia und changes the colors of the whole screen in real-time.
It's very nice because it works transparently in all applications (even within Youtube-Videos), but it will only work where Compiz is available, e.g. only under Linux.
Here's an article that has some guidelines for optimizing UI for color blind users:
Particletree » Be Kind to the Color Blind
It contains a link to another article with the kind of tools you were asking for:
10 colour contrast checking tools to improve the accessibility of your design | 456 Berea Street
A great paper that explains a conversion that preserves color differences is:
Detail Preserving Reproduction of color images for Monochromats and Dichromats.(PDF)
I haven't implemented the filter, but I plan to when I have some more free time.
I found Colour Simulations easy to use on Windows 10. This software can apply a color-blind filter to a part of the screen or the whole screen. And what's great is it allows me to interact with my PC normally as if it doesn't exist in fullscreen mode. It runs quite slow in my 4K screen using an integrated graphics card, though.

What's the best tradeoff between text and icons on buttons? [closed]

Closed. This question is off-topic. It is not currently accepting answers.
Want to improve this question? Update the question so it's on-topic for Stack Overflow.
Closed 9 years ago.
Improve this question
In a discussion with co-workers today, I lamented that I can't ever remember what an icon means, and have to hover over them to see the tooltips, and thus to find the button I need.
On their side, they were saying that when the text needs to be translated, it might not fit (German vs English for example), and that every place where there is text, including tooltips, it needs a translation. So plain icons are easier.
What is the best tradeoff in useability for the extra work of text vs the subset of users who are icon-challanged?
I personally prefer text and hate icon-only UI's. I know that other people think the other way, equally strongly, either because of internationalization or because their brain works more rapidly with images than with text. If you choose one or the other exclusively for your UI, then part of your user base will be unhappy with your choice. (Sometimes this is the right choice, depending on how extensively the UI will be used.)
Internationalization is really not that difficult, except for finding a firm to do good translations of your text. The programmer portion of internationalization is pretty straightforward. However, I've known a number of programmers who prefer the all-icon method as it's less work. I've personally had to replace one all-icon-no-text UI that the users didn't like. The users said they could not remember what the icons meant.
I think more typically, many advanced users will prefer icons and many beginning users will prefer text. However, a number of advanced users prefer text. IMHO, any good UI will provide tooltips, so you need to translate your interface no matter what you do.
The most friendly solution is to offer both text and icons, possibly with a settings choice to disable one or the other.
I worked with people in a Human/Computer Interactions group and was raked over the coals for using icon-only. They had studies about comprehension, error rate, and speed of using UI's and a good icon/label combination won every time, all else being equal.
Localization should be a non-issue. You may have to localize the icons anyway and localizing a label (as long as it's stored as text and not as bits) is easy. In terms of size in the UI - that's another matter entirely. If you can't fit the text, I'd claim that your UI is too cluttered.
Really they both have advantages and draw backs. Text must always be translated into different langugues, and sometimes a single word will not be able to effectively describe the action of a button. For example, how would you describe the X button which closes a window in Windows. We know what it does, and most people I know call it the X button, but it doesn't describe what it does. It's a lot easier to put a button with an X symbol (or icon if you will) than put something like "close window".
That being said icons also have drawbacks. As you eluded they may not always be clear what they do. The user has to be able to put the icon in a social context to understand what it does. This may not always be possible. Also, icons in one language may not be understood in another, leading back to the translation problem. Icons can be advantageous in certain areas as they can take a complex concept and show the user with a small amount of space. (like to take a picture show a camera, or delete something showing trash can).
The trade off is really in a case by case basis. If you have power users who really understand the application they are using and the surrounding subject, you are probably ok with using them. If you have people who use computers once a month and don't really care to learn it is going to be confusing. Its the amount of information you can convey with a single symbol (icon, picture, letter) vs. the potential frustration of the users and the overall rejection of your program.
Make sure you have a way to get both. Screen readers have a horrible time with icons.
I hate icons, because I never know what they mean even if they're perfectly intuitive (like this world icon that means hyperlink above this box in which I'm typing). Several Unix terminal applications provide a choice between:
text
graphical icons
both
That's nice. I usually like the text on a prominent button, because the meaning of the button is much more clear and the mouse target can be a little bigger.
Its a cultural thing as some symbols (icons) mean different things to people of different cultures, backgrounds and experiences. There are global symbols that one could assume to be 'known' by the general population, i.e. the 'save' icon...
It is a fine line, but i think the tooltips are a good way to help out those who dont understand the meaning of the icon. Perhaps a set of options to have the buttons (icons) render with text instead of the icon image ? This could be a user preference in the application.
Perhaps a good reference would be some of the "extensively" used icons in microsoft applications such as 'Word'. I am generalising here, but microsoft applications are almost eveywhere and they have done all the R&D into suitable / effective icons.
You don't mention if this is for a web application, but if it is then you have to provide the text at least as a backup if the user has disabled images, is using a screen reader, or other limited interface.
two things i guess
the decision should be the result of usability research and properly quantified, rather than a dev's gut feel or whim.
an icon that doesn't carry an obvious meaning is a bad icon and should be changed.
all that said, IMO: Icons with a tooltip/mouseover text equivalent, with bonus that this can carry a reminder of the keyboard shortcut.
(Note: I use "button" here to mean "the UI element on which the icon and/or text is located.")
I think in almost all cases it's important to include text either on the button itself, or at least on a hover-over tooltip on the button, so that in the event that the icon's meaning isn't intuitive to a particular user, the user can find out the meaning by reading the text. (Note that the translation work still needs to be performed in either case.)
A typical case for not including text directly on the button itself is when space is at a premium; when you want to fit a lot of buttons into a small area. Examples include the "toolbars" used in many desktop applications, and also in some web applications -- for example, the buttons that appear just above the StackOverflow answer text entry field!
A good case for including icons is when the button doesn't always appear in the same place, and the user would benefit from being able to quickly visually scan for where the button is located. For example, if I have a lot of programs open on Windows and I want to quickly find my instance of Firefox in the Windows taskbar, I'll look for the little orange icon, rather than reading the text on each taskbar button.

Resources