FLexecButton
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## FLexecButton

FLexecButton — A FLTK widget opcode that creates a button that executes a command.

## Description

A FLTK widget opcode that creates a button that executes a command. Useful for opening up HTML documentation as About text or to start a separate program from an FLTK widget interface.

| Warning
Because any command can be executed, the user is advised to be very careful when using this opcode and when running orchestras by others using this opcode.

## Syntax

    ihandle FLexecButton "command", iwidth, iheight, ix, iy

## Initialization

ihandle -- a handle value (an integer number) that unequivocally references a corresponding widget. This is used by other opcodes that modify a widget's properties (see Modifying FLTK Widget Appearance). It is automatically output by FLexecButton.

“command” -- a double-quoted string containing a command to execute.

Notice that with FLexecButton, the default text for the button is "About" and it is necessary to call the FLsetText opcode to change the text of the button.

iwidth -- width of widget.

iheight -- height of widget.

ix -- horizontal position of upper left corner of the valuator, relative to the upper left corner of corresponding window (expressed in pixels).

iy -- vertical position of upper left corner of the valuator, relative to the upper left corner of corresponding window (expressed in pixels).

## Examples

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

Example 157. Example of the FLexecButton opcode.

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

    <CsoundSynthesizer>
    <CsOptions>
    ; Select audio/midi flags here according to platform
    ; Audio out   Audio in    No display
    -odac           -iadc     -d     ;;;RT audio I/O
    </CsOptions>
    <CsInstruments>

      sr	    =  44100
      ksmps	    =  10
      nchnls    =  1

    ; Example by Jonathan Murphy 2007

    ;;; reset amplitude range
      0dbfs	    =  1

    ;;; set the base colour for the panel
    	    FLcolor   100, 0, 200
    ;;; define the panel
    	    FLpanel   "FLexecButton", 250, 100, 0, 0
    ;;; sliders to control time stretch and pitch
      gkstr, gistretch    FLslider			  "Time", 0.5, 1.5, 0, 6, -1, 10, 60, 150, 20
      gkpch, gipitch      FLslider			  "Pitch", 0.5, 1.5, 0, 6, -1, 10, 60, 200, 20
    ;;; set FLexecButton colour
    	    FLcolor   255, 255, 0
    ;;; when this button is pressed, fourier analysis is performed on the file
    ;;; "beats.wav", producing the analysis file "beats.pvx"
      gipvoc    FLexecButton  "csound -U pvanal beats.wav beats.pvx", 60, 20, 20, 20
    ;;; set FLexecButton text
    	    FLsetText	"PVOC", gipvoc
    ;;; when this button is pressed, instr 10000 is called, exiting
    ;;; Csound immediately

    ;;; cancel previous  colour
    	    FLcolor   -1
    ;;; set colour for kill button
    	    FLcolor   255, 0, 0
      gkkill, gikill      FLbutton			  "X", 1, 1, 1, 20, 20, 100, 20, 0, 10000, 0, 0.1
    ;;; cancel previous colour
    	    FLcolor   -1
    ;;; set colour for play/stop and pause buttons
    	    FLcolor   0, 200, 0
    ;;; pause and play/stop buttons
      gkpause, gipause    FLbutton			  "@||", 1, 0, 2, 40, 20, 20, 60, -1
      gkplay, giplay      FLbutton			  "@|>", 1, 0, 2, 40, 20, 80, 60, -1
    ;;; end the panel
    	    FLpanelEnd
    ;;; set initial values for time stretch and pitch
    	    FLsetVal_i	1, gistretch
    	    FLsetVal_i	1, gipitch
    ;;; run the panel
    	    FLrun

        instr 1					  ; trigger play/stop
    ;;; is the play/stop button on or off?
    ;;; either way we need to trigger something,
    ;;; so we can't just use the value of gkplay
      kon	    trigger   gkplay, 0, 0
      koff	    trigger   gkplay, 1, 1
    ;;; if on, start instr 2
    	    schedkwhen	kon, -1, -1, 2, 0, -1
    ;;; if off, stop instr 2
    	    schedkwhen	koff, -1, -1, -2, 0, -1

        endin

        instr 2

    ;;; paused or playing?
    if (gkpause == 1) kgoto pause
    	    kgoto     start
    pause:
    ;;; if the pause button is on, skip sound production
    	    kgoto     end
    start:
    ;;; get the length of the analysis file in seconds
      ilen	    filelen   "beats.pvx"
    ;;; determine base frequency of playback
      icps	    =  1/ilen
    ;;; create a table over the length of the file
      itpt	    ftgen     0, 0, 513, -7, 0, 512, ilen
    ;;; phasor for time control
      kphs	    phasor    icps * gkstr
    ;;; use phasor as index into table
      kndx	    =  kphs * 512
    ;;; read table
      ktpt	    tablei    kndx, itpt
    ;;; use value from table as time pointer into file
      fsig1	    pvsfread  ktpt, "beats.pvx"
    ;;; change playback pitch
      fsig2	    pvscale   fsig1, gkpch
    ;;; resynthesize
      aout	    pvsynth   fsig2
    ;;; envelope to avoid clicks and clipping
      aenv	    linsegr   0, 0.3, 0.75, 0.1, 0
      aout	    =  aout * aenv
    	    out	      aout
    end:

        endin

        instr 10000					  ; kill

    	    exitnow

        endin

    </CsInstruments>
    <CsScore>
    i1 0 10000
    e
    </CsScore>
    </CsoundSynthesizer>

## See Also

FLbutton, FLbox, FLbutBank, FLprintk, FLprintk2, FLvalue

## Credits

Author: Steven Yi

Example by: Jonathan Murphy

New in version 5.05

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