x coordinate to sample
y coordinate to sample
matrix representing extent of sampling area in source buffer.
memory location for output data.
how requests outside the buffer extent are handled. Valid values: GEGL_ABYSS_NONE (abyss pixels are zeroed), GEGL_ABYSS_WHITE (abyss pixels are white), GEGL_ABYSS_BLACK (abyss pixels are black), GEGL_ABYSS_CLAMP (coordinates are clamped to the abyss rectangle), GEGL_ABYSS_LOOP (buffer contents are tiled if outside of the abyss rectangle).
Perform a sampling with the provided