The Get Regions Of Interest Action

	#include "ofxImageEffect.h"
	#define kOfxImageEffectActionGetRegionsOfInterest         "OfxImageEffectActionGetRegionsOfInterest"

  • handle handle to the instance, cast to an OfxImageEffectHandle ,
  • inArgs has the following properties...
  • outArgs has a set of 4 dimensional double properties, one for each of the input clips to the effect. The properties are each named "OfxImageClipPropRoI_" with the clip name post pended, for example "OfxImageClipPropRoI_Source". These are initialised to the default RoI.


This action allows a host to ask an effect, given a region I want to render, what region do you need from each of your input clips. In that way, depending on the host architecture, a host can fetch the minimal amount of the image needed as input. Note that there is a region of interest to be set in outArgs for each input clip that exists on the effect. Form more details see Image Effect Architectures .

Return Values

  • kOfxStatOK, the action was trapped and at least one RoI was set in the outArgs property set
  • kOfxStatReplyDefault, the action was not trapped and the host should use the default values
  • kOfxStatErrMemory, in which case the action may be called again after a memory purge
  • kOfxStatFailed, something wrong, but no error code appropriate, plugin to post message
  • kOfxStatErrFatal

Default Action

The default RoI is simply the value passed in on the kOfxImageEffectPropRegionOfInterest inArgs property set. All the RoIs in the outArgs property set must initialised to this value before the action is called.