FLkeyIn — Reports keys pressed (on alphanumeric keyboard) when an FLTK panel has focus.


Plugin opcode in widgets. This opcode is part of the plugin repository and has to be installed separately. These FLTK widgets do not work on the Mac. The plugin repository can be found here: https://github.com/csound/plugins

FLkeyIn informs about the status of a key pressed by the user on the alphanumeric keyboard when an FLTK panel has got the focus.


kascii FLkeyIn [ifn]


ifn – (optional, default value is zero) set the behavior of FLkeyIn (see below).


kascii - the ascii value of last pressed key. If the key is pressed, the value is positive, when the key is released the value is negative.

FLkeyIn is useful to know whether a key has been pressed on the computer keyboard. The behavior of this opcode depends on the optional ifn argument.

If ifn = 0 (default), FLkeyIn outputs the ascii code of the last pressed key. If it is a special key (ctrl, shift, alt, f1-f12 etc.), a value of 256 is added to the output value in order to distinguish it from normal keys. The output will continue to output the last key value, until a new key is pressed or released. Notice that the output will be negative when a key is depressed.

If ifn is set to the number of an already-allocated table having at least 512 elements, then the table element having index equal to the ascii code of the key pressed is set to 1, all other table elements are set to 0. This allows to check the state of a certain key or set of keys.

Be aware that you must set the ikbdcapture parameter to something other than 0 on a designated FLpanel for FLkeyIn to capture keyboard events from that panel.

[Note] Note

FLkeyIn works internally at k-rate, so it cannot be used in the header as other FLTK opcodes. It must be used inside an instrument.


Here is an example of the FLkeyIn opcode. It uses the file FLkeyIn.csd.

Example 319. Example of the FLkeyIn opcode.

See the sections Real-time Audio and Command Line Flags for more information on using command line flags.

; Select audio/midi flags here according to platform
; Audio out   Audio in    No messages
-odac           -iadc     -d     ;;;RT audio I/O


;Example by Andres Cabrera 2007

FLpanel "FLkeyIn", 400, 300, -1, -1, 5, 1, 1


0dbfs = 1

instr 1
kascii   FLkeyIn
ktrig changed kascii
if (kascii > 0) then
  printf "Key Down: %i\n", ktrig, kascii
  printf "Key Up: %i\n", ktrig, -kascii

i 1 0 120



Author: Gabriel Maldonado

New in version 5.06