WTImageTrackerDelegate Protocol Reference
| Conforms to | NSObject |
|---|---|
| Declared in | WTImageTracker.h |
Overview
@Brief WTImageTrackerDelegate provides methods that propagate information about tracker state changes.
Tracker objects are not created by calling their init method, but through the provided factory methods of WTTrackerManager.
Matrix pointer that are provided inside the WTImageTarget objects are only valid in the current method scope. If they are needed at a later point in time, they have to be copied into different memory that is controlled by the Wikitude Native SDK hosting application.
– imageTracker:didRecognizeImage:
required method
@Brief Called whenever a tracker recognizes a new image target that was previously unknown.
- (void)imageTracker:(nonnull WTImageTracker *)imageTracker didRecognizeImage:(nonnull WTImageTarget *)recognizedTargetParameters
imageTracker |
The tracker object that recognized the new image target |
|---|---|
recognizedTarget |
The image target that was recognised. |
Discussion
All WTImageTarget matrix pointer are set to nullptr and should not be used.
Declared In
WTImageTracker.h
– imageTracker:didTrackImage:
required method
Called whenever a previously known image target was tracked again.
- (void)imageTracker:(nonnull WTImageTracker *)imageTracker didTrackImage:(nonnull WTImageTarget *)trackedTargetParameters
imageTracker |
The tracker object that tracked the image target |
|---|---|
trackedTarget |
The image target tat was tracked again |
Declared In
WTImageTracker.h
– imageTracker:didLoseImage:
required method
Called whenever a previously know image target is not found anymore in the current camera frame.
- (void)imageTracker:(nonnull WTImageTracker *)imageTracker didLoseImage:(nonnull WTImageTarget *)lostTargetParameters
imageTracker |
The tracker object that lost the image target. |
|---|---|
lostTarget |
The image target that was lost |
Discussion
All WTImageTarget matrix pointer are set to nullptr and should not be used.
Declared In
WTImageTracker.h
– imageTrackerDidLoadTargets:
Called when an image tracker was successfully initialized.
- (void)imageTrackerDidLoadTargets:(nonnull WTImageTracker *)imageTrackerParameters
imageTracker |
The image tracker that was initialized |
|---|
Declared In
WTImageTracker.h
– imageTracker:didFailToLoadTargets:
Called whenever an image tracker could not be initialized.
- (void)imageTracker:(nonnull WTImageTracker *)imageTracker didFailToLoadTargets:(nonnull NSError *)errorParameters
imageTracker |
The image tracker that could not be initialized |
|---|---|
error |
A NSError object that contains more information about why the image tracker could not be initialized |
Declared In
WTImageTracker.h
– imageTracker:didUpdateExtendedTrackingQualityForTarget:fromQuality:toQuality:
Called whenever a tracker is marked to be extended and the extended tracking quality changes.
During a tracking session, the extended tracking quality might get better or worse, depending on the scene that is captured.
- (void)imageTracker:(nonnull WTImageTracker *)imageTracker didUpdateExtendedTrackingQualityForTarget:(NSString *)extendedTarget fromQuality:(WTExtendedTrackingQuality)oldTrackingQuality toQuality:(WTExtendedTrackingQuality)newTrackingQualityParameters
imageTracker |
The tracker object that changed the extended tracking quality |
|---|---|
extendedTarget |
The name of the image target that changed the extended tracking quality |
oldTrackingQuality |
The previously extended tracking quality |
newTrackingQuality |
The extended tracking quality that is now reached |
Discussion
This method is also called when extended tracking processed the first frame, meaning that oldTrackingQuality is then set to a non WTExtendedTrackingQuality value.
Declared In
WTImageTracker.h