Method: Magick::Image#stegano

Defined in:
ext/RMagick/rmimage.cpp

#stegano(watermark_image, offset) ⇒ Magick::Image

Hides a digital watermark in the receiver. You can retrieve the watermark by reading the file with the stegano: prefix, thereby proving the authenticity of the file.

The watermarked image must be saved in a lossless RGB format such as MIFF, or PNG. You cannot save a watermarked image in a lossy format such as JPEG or a pseudocolor format such as GIF. Once written, the file must not be modified or processed in any way.

Parameters:

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

    Either an imagelist or an image

  • offset (Numeric) —

    the start position within the image to hide the watermark.

Returns:



13724
13725
13726
13727
13728
13729
13730
13731
13732
13733
13734
13735
13736
13737
13738
13739
13740
13741
13742
13743
13744
13745
13746
13747
13748
13749
 
# File 'ext/RMagick/rmimage.cpp', line 13724

VALUE
Image_stegano(VALUE self, VALUE watermark_image, VALUE offset)
{
    Image *image, *new_image;
    VALUE wm_image;
    Image *watermark;
    ExceptionInfo *exception;

    image = rm_check_destroyed(self);

    wm_image = rm_cur_image(watermark_image);
    watermark = rm_check_destroyed(wm_image);

    image->offset = NUM2LONG(offset);

    exception = AcquireExceptionInfo();
    GVL_STRUCT_TYPE(SteganoImage) args = { image, watermark, exception };
    new_image = (Image *)CALL_FUNC_WITHOUT_GVL(GVL_FUNC(SteganoImage), &args);
    rm_check_exception(exception, new_image, DestroyOnError);

    DestroyExceptionInfo(exception);

    RB_GC_GUARD(wm_image);

    return rm_image_new(new_image);
}