getkey

Get a single keypress (v1.2 apr 2009)

Description

GETKEY - get a single keypress

CH = GETKEY waits for a keypress and returns the ASCII code. Accepts all ascii characters, including backspace (8), space (32), enter (13), etc, that can be typed on the keyboard. Non-ascii keys (ctrl, alt, ..) return a NaN. CH is a double.
 
CH = GETKEY('non-ascii') uses non-documented matlab 6.5 features to return a string describing the key pressed. In this way keys like ctrl, alt, tab etc. can also distinguished. CH is a string.

This function is kind of a workaround for getch in C. It uses a modal, but non-visible window, which does show up in the taskbar.

Tested for ML versions 6.5 and up

• Acknowledgements: This submission has inspired the following:; GETKEYNOW, YESNO, GetKeyWait
• MATLAB release: MATLAB 6.5 (R13)

[Chris Brown]

The INPUT function in R13 contains a bug that does not flush the keyboard buffer while within loops, meaning that after so many calls the keyboard will stop working.

As a result, getkey is especially useful to me. Thank you for making it available.

[Dimitri Shvorob]

Chris, could you elaborate please? Running
'for i = 1:100, a = input('Enter a letter','s'), end', I didn't see any irregularities. (How many is so many?)
Jos, maybe you could write a companion function that outputs the key pressed now, rather than waits for one, as INPUT? I don't really know of any way - including via 'currentkey' figure property - to do that in Matlab, and a solution would be very helpful.
Thank you.

[George Aumann]

Just what I was looking for.

[Patrick Craston]

Great! been searching for something like this for ages..

[Erik Helberg]

 

[fred klugger]

How can I use this?

[Jos van der Geest]

to Fred Kluger: you may use this wherever you want a single key response from the user. You can use it in similar way as you would use <input> (which requires an additional "enter")

to Erik: ??

Jos

[Jay Vaughan]

Did the job perfectly for me.

[Jens Rantil]

This program is unnecvessary as it can be done using
[ignore,ignore2,keycode]=ginput(1);

[Jos (the author)]

To Jens Rantil: GETKEY is not at all as trivial as your code implies. For instance, GINPUT needs an axis (and will create one if none exist) and can capture only a few keys.
GETKEY has none of this behavior, and is much more flexible as it can be used in codes without graphical output.

[gregor samsa]

Good job. Worked for me