Environment

Some environment variables can be set to alter how GEGL runs, these options are also available as properties on a singleton GObject returned from gegl_config(). The defaults should be what one normally use - overriding

GEGL_MIPMAP_RENDERING

[true, false] default: false
Render output as an image preview mipmap. 1 and yes are synonyms for true, everything else is taken as false.

GEGL_QUALITY

[0.0-1.0, fast, good, best] default: 1.0
The quality of the rendering, a value between 0.0 (fast) and 1.0 (reference). The values fast, good and best are also accepted as synonyms for 0.0, 0.5 and 1.0 respectively.

BABL_TOLERANCE

[0.0-1.0] default: 0.000001
Controls a accuracy/performance trade off with low values representing high numerical accuracy. By default BABL_TOLERANCE is set to a very low (0.000001) value. Values in the range 0.01-0.1 are suitable for providing preview images with reasonable performance an accuracy.

GEGL_CACHE_SIZE

The size, in megabytes, of the tile cache used by GeglBuffer.

GEGL_CHUNK_SIZE

The number of pixels processed simultaneously.

GEGL_TILE_SIZE

[<width>x<height>] default: 128x64
The tile size used internally by GEGL, in pixels.

GEGL_THREADS

[1-64]
Number of threads to use. Setting to 1 ensures single threaded processing.

GEGL_SWAP

The directory where temporary swap files are written. If not specified GEGL will not swap to disk.

GEGL_DEBUG

[process, cache, buffer-load, buffer-save, tile-backend, processor, invalidation, opencl, license, all]
Enable internal debug tooling on one or more domains - all enables all debug domains.

GEGL_DEBUG_BUFS

Display tile/buffer leakage statistics.

GEGL_DEBUG_RECTS

Show the results of have/need rect negotiations.

GEGL_DEBUG_TIME

Setting to any value will print a performance instrumentation breakdown of GEGL and it’s operations.

GEGL_USE_OPENCL

[yes, no, cpu, gpu, accelerator]
Enable use of OpenCL processing.

GEGL_PATH

The directory where GEGL looks (recursively) for dynamically loadable operation libraries.

BABL_PATH

The directory containing babl extensions, both new pixel formats/color models as well as fast-paths for efficient pixel format conversions.