imagegetpixel
Prev | Orchestra Opcodes and Operators | Next

## imagegetpixel

imagegetpixel — Return the RGB pixel values of a previously opened or created image.

## Description

Plugin opcode in image.

Return the RGB pixel values of a previously opened or created image. An image can be loaded with imageload. An empty image can be created with imagecreate.

## Syntax

    ared, agreen, ablue imagegetpixel iimagenum, ax, ay

    kred, kgreen, kblue imagegetpixel iimagenum, kx, ky

## Initialization

iimagenum -- the reference of the image.. It should be a value returned by imageload or imagecreate.

## Performance

ax (kx) -- horizontal pixel position (must be a float from 0 to 1).

ay (ky) -- vertical pixel position (must be a float from 0 to 1).

ared (kred) -- red value of the pixel (mapped to a float from 0 to 1).

agreen (kgreen) -- green value of the pixel (mapped to a float from 0 to 1).

ablue (kblue) -- blue value of the pixel (mapped to a float from 0 to 1).

## Examples

Here is an example of the imagegetpixel opcode. It uses the files imageopcodesdemo2.csd test1.png and test2.png.

Example 454. Example of the imagegetpixel opcode.

    <CsoundSynthesizer>

    <CsOptions>
    ; Select audio/midi flags here according to platform
    ; Audio out   Audio in
    -odac           -iadc    ;;;RT audio I/O
    ; For Non-realtime ouput leave only the line below:
    ; -o imageopcodesdemo2.wav -W ;;; for file output any platform
    </CsOptions>

    <CsInstruments>
    sr      =      	48000
    ksmps  	=     	100
    nchnls	=	2

    ;By Cesare Marilungo 2008
    zakinit 10,1

    ;Load the image - should be 512x512 pixels
    giimage imageload "test1.png"
    ;giimage imageload "test2.png" ;--try this too
    giimagew, giimageh imagesize giimage

    giwave ftgen 1, 0, 1024, 10, 1
    gifrqs ftgen 2,0,512,-5, 1,512,10
    giamps ftgen 3, 0, 512, 10, 1

    	instr 100

    kindex = 0
    icnt = giimageh
    kx_ linseg 0, p3, 1
    kenv linseg 0, .2, 500, p3 - .4, 500, .2, 0

    ; Read a column of pixels and store the red values
    ; inside the table 'giamps'
    loop:
        ky_ = kindex/giimageh

        ;Get the pixel color values at kx_, ky_
        kred, kgreen, kblue imagegetpixel giimage, kx_, ky_

        ;Write the red values inside the table 'giamps'
        tablew kred, kindex, giamps
        kindex = kindex+1

    if (kindex < icnt) kgoto loop

    ; Use an oscillator bank (additive synthesis) to generate sound
    ; setting amplitudes for each partial according to the image
    asig adsynt kenv, 220, giwave, gifrqs, giamps, icnt, 2
    outs asig, asig

    	endin

    	instr 101
    ; Free memory used by the image
    imagefree giimage
    	endin

    </CsInstruments>
    <CsScore>

    t 0 60

    i100 1 20
    i101 21 1

    e

    </CsScore>
    </CsoundSynthesizer>

## See Also

imageload, imagecreate, imagesize, imagesave, imagesetpixel, imagefree

## Credits

Author: Cesare Marilungo

New in version 5.08

Prev | Up | Next
imagefree | Home | imageload