line
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## line

line — Trace a straight line between specified points.

## Description

Trace a straight line between specified points.

## Syntax

    ares line ia, idur1, ib

    kres line ia, idur1, ib

## Initialization

ia -- starting value. Zero is illegal for exponentials.

ib, ic, etc. -- value after dur1 seconds, etc. For exponentials, must be non-zero and must agree in sign with ia.

idur1 -- duration in seconds of first segment. A zero or negative value will cause all initialization to be skipped.

## Performance

These units generate control or audio signals whose values can pass through 2 or more specified points. The sum of dur values may or may not equal the instrument's performance time: a shorter performance will truncate the specified pattern, while a longer one will cause the last-defined segment to continue on in the same direction.

| Note

A common error with this opcode is to assume that the value of ib is the held after the time idur1. line does not automatically end or stop at the end of the duration given. If your note length is longer than idur1 seconds, kres (or ares) will not come to rest at ib, but will instead continue to rise or fall with the same rate. If a rise (or fall) and then hold is required that the linseg opcode should be considered instead.

## Examples

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

Example 239. Example of the line 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 messages
    -odac           -iadc     -d     ;;;RT audio I/O
    ; For Non-realtime ouput leave only the line below:
    ; -o line.wav -W ;;; for file output any platform
    </CsOptions>
    <CsInstruments>

    ; Initialize the global variables.
    sr = 44100
    kr = 4410
    ksmps = 10
    nchnls = 1

    ; Instrument #1.
    instr 1
      ; Define kcps as a frequency value that linearly declines
      ; from 880 to 220. It declines over the period set by p3.
      kcps line 880, p3, 220

      a1 oscil 20000, kcps, 1
      out a1
    endin

    instr 2
      kcps line 880, 1, 660   ; kcps won't stop at 660 if p3 > 1
      a1 oscil 20000, kcps, 1
      out a1
    endin

    instr 3
      kcps line 880, 1, 660, 1, 660   ; kcps will stay at 660 after 1 sec.
      a1 oscil 20000, kcps, 1
      out a1
    endin

    </CsInstruments>
    <CsScore>

    ; Table #1, a sine wave.
    f 1 0 16384 10 1

    ; Play Instrument #1 for two seconds.
    i 1 0 2

    i 2 3 2

    i 3 6 2
    e

    </CsScore>
    </CsoundSynthesizer>

## See Also

expon, expseg, expsegr, linseg, linsegr

## Credits

Example written by Kevin Conder.

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