Method: Magick::Image#contrast

Defined in:
ext/RMagick/rmimage.cpp

#contrast(sharpen = false) ⇒ Magick::Image

Enhance the intensity differences between the lighter and darker elements of the image.

Returns a new image.

Parameters:

  • sharpen (Boolean) (defaults to: false) —

    If sharpen is true, the contrast is increased, otherwise it is reduced.

Returns:



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# File 'ext/RMagick/rmimage.cpp', line 4512

VALUE
Image_contrast(int argc, VALUE *argv, VALUE self)
{
    Image *image, *new_image;
    MagickBooleanType sharpen = MagickFalse;
#if defined(IMAGEMAGICK_7)
    ExceptionInfo *exception;
#endif

    image = rm_check_destroyed(self);
    if (argc > 1)
    {
        rb_raise(rb_eArgError, "wrong number of arguments (%d for 0 or 1)", argc);
    }
    else if (argc == 1)
    {
        sharpen = (MagickBooleanType)RTEST(argv[0]);
    }

    new_image = rm_clone_image(image);

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

    return rm_image_new(new_image);
}