What some non-obvious terms mean in Blitline

There are some image processing terms that may not make sense to those unfamiliar with ImageMagick or Blitline.


Gravity defines where a selection should be placed within the context of an image.

For example: WestGravity would mean "left-align" the image

There are 10 different possible gravity settings:

  • CenterGravity
  • NorthWestGravity
  • NorthGravity
  • NorthEastGravity
  • EastGravity
  • SouthEastGravity
  • SouthGravity
  • SouthWestGravity
  • WestGravity


During a composite operation (which overlays one image on top of another), there are many different ways the images can be combined together.

You can read more about them here: https://legacy.imagemagick.org/Usage/compose/

Generally you will normally just use the defaults.