Method: Magick::Image#black_threshold

Defined in:

ext/RMagick/rmimage.cpp

#black_threshold(red) ⇒ Numeric #black_threshold(red, green) ⇒ Numeric #black_threshold(red, green, blue) ⇒ Numeric #black_threshold(red, green, blue, alpha: ) ⇒ Numeric

Forces all pixels below the threshold into black while leaving all pixels above the threshold unchanged.

Overloads:

• #black_threshold(red) ⇒ Numeric

  Parameters:

  • red (Numeric) —

    the number for red channel

• #black_threshold(red, green) ⇒ Numeric

  Parameters:

  • red (Numeric) —

    the number for red channel

  • green (Numeric) —

    the number for green channel

• #black_threshold(red, green, blue) ⇒ Numeric

  Parameters:

  • red (Numeric) —

    the number for red channel

  • green (Numeric) —

    the number for green channel

  • blue (Numeric) —

    the number for blue channel

• #black_threshold(red, green, blue, alpha: ) ⇒ Numeric

  Parameters:

  • red (Numeric) —

    the number for red channel

  • green (Numeric) —

    the number for green channel

  • blue (Numeric) —

    the number for blue channel

  • alpha (Numeric) (defaults to: ) —

    the number for alpha channel

Returns:

• (Numeric) —

  a new image

See Also:

• #white_threshold

# File 'ext/RMagick/rmimage.cpp', line 1585

VALUE
Image_black_threshold(int argc, VALUE *argv, VALUE self)
{
    return threshold_image(argc, argv, self, GVL_FUNC(BlackThresholdImage));
}