Method: Magick::Image#distortion_channel

Defined in:

ext/RMagick/rmimage.cpp

#distortion_channel(reconstructed_image, metric, channel = Magick::AllChannels) ⇒ Float #distortion_channel(reconstructed_image, metric, *channels) ⇒ Float

Compares one or more image channels of an image to a reconstructed image and returns the specified distortion metric.

Overloads:

• #distortion_channel(reconstructed_image, metric, channel = Magick::AllChannels) ⇒ Float

  Parameters:

  • reconstructed_image (Magick::Image, Magick::ImageList) —

    Either an imagelist or an image. If an imagelist, uses the current image.

  • metric (Magick::MetricType) —

    The desired distortion metric.

  • channel (Magick::ChannelType) (defaults to: Magick::AllChannels) —

    a ChannelType arguments.

• #distortion_channel(reconstructed_image, metric, *channels) ⇒ Float

  Parameters:

  • reconstructed_image (Magick::Image, Magick::ImageList) —

    Either an imagelist or an image. If an imagelist, uses the current image.

  • metric (Magick::MetricType) —

    The desired distortion metric.

  • *channels (Magick::ChannelType) —

    one or more ChannelType arguments.

Returns:

• (Float) —

  the image channel distortion

# File 'ext/RMagick/rmimage.cpp', line 6011

VALUE
Image_distortion_channel(int argc, VALUE *argv, VALUE self)
{
    Image *image, *reconstruct;
    ChannelType channels;
    ExceptionInfo *exception;
    MetricType metric;
    VALUE rec;
    double distortion;
#if defined(IMAGEMAGICK_7)
    Image *difference_image;
#endif

    image = rm_check_destroyed(self);
    channels = extract_channels(&argc, argv);
    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);
    }

    rec = rm_cur_image(argv[0]);
    reconstruct = rm_check_destroyed(rec);
    VALUE_TO_ENUM(argv[1], metric, MetricType);
    exception = AcquireExceptionInfo();
#if defined(IMAGEMAGICK_7)
    BEGIN_CHANNEL_MASK(image, channels);
    GVL_STRUCT_TYPE(CompareImages) args = { image, reconstruct, metric, &distortion, exception };
    difference_image = (Image *)CALL_FUNC_WITHOUT_GVL(GVL_FUNC(CompareImages), &args);
    END_CHANNEL_MASK(image);
    DestroyImage(difference_image);
#else
    GVL_STRUCT_TYPE(GetImageChannelDistortion) args = { image, reconstruct, channels, metric, &distortion, exception };
    CALL_FUNC_WITHOUT_GVL(GVL_FUNC(GetImageChannelDistortion), &args);
#endif

    CHECK_EXCEPTION();

    DestroyExceptionInfo(exception);

    RB_GC_GUARD(rec);

    return rb_float_new(distortion);
}