Method: Magick::Image#modulate

Defined in:
ext/RMagick/rmimage.cpp

#modulate(brightness = 1.0, saturation = 1.0, hue = 1.0) ⇒ Magick::Image

Changes the brightness, saturation, and hue.

Returns a new image.

Parameters:

  • brightness (Numeric, String) (defaults to: 1.0) —

    The percent change in the brightness. Must be a non-negative number or a string in the form “NN%”.

  • saturation (Numeric, String) (defaults to: 1.0) —

    The percent change in the saturation. Must be a number or a string in the form “NN%”.

  • hue (Numeric, String) (defaults to: 1.0) —

    The percent change in the hue. Must be a number or a string in the form “NN%”.

Returns:



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# File 'ext/RMagick/rmimage.cpp', line 9570

VALUE
Image_modulate(int argc, VALUE *argv, VALUE self)
{
    Image *image, *new_image;
    double pct_brightness = 100.0,
    pct_saturation = 100.0,
    pct_hue        = 100.0;
    char modulate[100];
#if defined(IMAGEMAGICK_7)
    ExceptionInfo *exception;
#endif

    image = rm_check_destroyed(self);
    switch (argc)
    {
        case 3:
            pct_hue        = rm_percentage2(argv[2], 1.0, false) * 100.0;
        case 2:
            pct_saturation = rm_percentage2(argv[1], 1.0, false) * 100.0;
        case 1:
            pct_brightness = rm_percentage(argv[0], 1.0) * 100.0;
            break;
        case 0:
            break;
        default:
            rb_raise(rb_eArgError, "wrong number of arguments (%d for 0 to 3)", argc);
            break;
    }

    if (pct_brightness <= 0.0)
    {
        rb_raise(rb_eArgError, "brightness is %g%%, must be positive", pct_brightness);
    }
    snprintf(modulate, sizeof(modulate), "%f%%,%f%%,%f%%", pct_brightness, pct_saturation, pct_hue);

    new_image = rm_clone_image(image);

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

    return rm_image_new(new_image);
}