Environment
~~~~~~~~~~~
Some environment variables can be set to alter how GEGL runs, all of these
options are also available as properties on a singleton GObject returned from
gegl_config ().

GEGL_QUALITY::
    A value between 0.0 and 1.0 indicating a trade-off between quality and
    speed. Defaults to 1.0 (max quality).
BABL_TOLERANCE::
    The amount of error that babl tolerates, set it to for instance 0.1 to use
    some conversions that trade some quality for speed.
GEGL_CHUNK_SIZE::
    The number of pixels processed simulatnously.
GEGL_TILE_SIZE::
    The tile size used internally by GEGL, defaults to 128x64
GEGL_SWAP::
    The directory where temporary swap files are written, if not specified GEGL
    will not swap to disk. Be aware that swapping to disk is still experimental
    and GEGL is currently not removing the per process swap files.
GEGL_CACHE_SIZE::
    The size of the tile cache used by GeglBuffer specified in megabytes.
GEGL_DEBUG::
    set it to "all" to enable all debugging, more specific domains for
    debugging information are also available.
BABL_STATS::
    When set babl will write a html file (/tmp/babl-stats.html) containing a
    matrix of used conversions, as well as all existing conversions and which
    optimized paths are followed.
GEGL_DEBUG_BUFS::
    Display tile/buffer leakage statistics.
GEGL_DEBUG_RECTS::
    Show the results of have/need rect negotiations.
GEGL_DEBUG_TIME::
    Print a performance instrumentation breakdown of GEGL and it's operations.
GEGL_USE_OPENCL:
    Enable use of OpenCL processing.
