Method: Magick::Image#threshold

Defined in:
ext/RMagick/rmimage.cpp

#threshold(threshold_obj) ⇒ Magick::Image

Change the value of individual pixels based on the intensity of each pixel compared to threshold. The result is a high-contrast, two color image.

Parameters:

  • threshold_obj (Numeric) —

    the threshold

Returns:



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# File 'ext/RMagick/rmimage.cpp', line 14162

VALUE
Image_threshold(VALUE self, VALUE threshold_obj)
{
    Image *image, *new_image;
    double threshold = NUM2DBL(threshold_obj);
#if defined(IMAGEMAGICK_7)
    ExceptionInfo *exception;
#endif

    image = rm_check_destroyed(self);
    new_image = rm_clone_image(image);

#if defined(IMAGEMAGICK_7)
    exception = AcquireExceptionInfo();
    GVL_STRUCT_TYPE(BilevelImage) args = { new_image, threshold, exception };
    CALL_FUNC_WITHOUT_GVL(GVL_FUNC(BilevelImage), &args);
    rm_check_exception(exception, new_image, DestroyOnError);
    DestroyExceptionInfo(exception);
#else
    GVL_STRUCT_TYPE(BilevelImageChannel) args = { new_image, DefaultChannels, threshold };
    CALL_FUNC_WITHOUT_GVL(GVL_FUNC(BilevelImageChannel), &args);
    rm_check_image_exception(new_image, DestroyOnError);
#endif

    return rm_image_new(new_image);
}