-/** @param reduce a factor by which to reduce the resolution
- * of the image, expressed as a power of two (pass 0 for no
- * reduction).
- * @param srgb_gamma Reciprocal of output gamma to use after
- * the conversion from XYZ to RGB.
- *
- * @return An ARGB representation of this frame. This is ARGB in the
- * Cairo sense, so that each pixel takes up 4 bytes; the first byte
- * is blue, second green, third red and fourth alpha (always 255).
- */
-shared_ptr<ARGBFrame>
-MonoPictureFrame::argb_frame (int reduce, float srgb_gamma) const