Method: Magick::Image#convolve_channel

Defined in:
ext/RMagick/rmimage.c

#convolve_channel(*args) ⇒ Object

call ConvolveImageChannel.

Ruby usage:

- @verbatim Image#convolve_channel(order, kernel) @endverbatim
- @verbatim Image#convolve_channel(order, kernel, channel) @endverbatim
- @verbatim Image#convolve_channel(order, kernel, channel, ...) @endverbatim

Parameters:

  • argc —

    number of input arguments

  • argv —

    array of input arguments

  • self —

    this object

Returns:

  • a new image

[View source]

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# File 'ext/RMagick/rmimage.c', line 4148

VALUE
Image_convolve_channel(int argc, VALUE *argv, VALUE self)
{
    Image *image, *new_image;
    double *kernel;
    volatile VALUE ary;
    unsigned int x, order;
    ChannelType channels;
    ExceptionInfo exception;

    image = rm_check_destroyed(self);

    channels = extract_channels(&argc, argv);

    // There are 2 required arguments.
    if (argc > 2)
    {
        raise_ChannelType_error(argv[argc-1]);
    }
    if (argc != 2)
    {
        rb_raise(rb_eArgError, "wrong number of arguments (%d for 2 or more)", argc);
    }

    order = NUM2UINT(argv[0]);
    ary = argv[1];

    rm_check_ary_len(ary, (long)(order*order));

    kernel = ALLOC_N(double, (long)(order*order));

    // Convert the kernel array argument to an array of doubles
    for (x = 0; x < order*order; x++)
    {
        kernel[x] = NUM2DBL(rb_ary_entry(ary, (long)x));
    }

    GetExceptionInfo(&exception);

    new_image = ConvolveImageChannel(image, channels, order, kernel, &exception);
    xfree((void *)kernel);
    rm_check_exception(&exception, new_image, DestroyOnError);

    (void) DestroyExceptionInfo(&exception);

    rm_ensure_result(new_image);

    return rm_image_new(new_image);
}