Package com.digimarc.dms.readers.image

Class PreviewDetectionRegion

java.lang.Object

com.digimarc.dms.readers.image.DetectionRegion

com.digimarc.dms.readers.image.PreviewDetectionRegion

public final class PreviewDetectionRegion
extends DetectionRegion

A DetectionRegion for restricting detection within a camera preview. A PreviewDetectionRegion must be created by the PreviewDetectionRegion.Builder. To construct a PreviewDetectionRegion.Builder a RectF is needed to describe the percentage of the frame that is visible in the camera preview.

A PreviewDetectionRegion is useful for apps that display a camera preview. The visible image within a camera preview is often a cropped region of the full camera frame. This class allows apps to restrict detection within this visible area. To further restrict the detection region within a sub-region of the visible image, such as a targeting area, apps can construct a PreviewDetectionRegion.Builder with PreviewDetectionRegion.Builder.setRegionOfInterest(RectF).

PreviewDetectionRegion is designed to accept regions relative to the display's orientation. Internally PreviewDetectionRegion will apply the rotation needed to project regions onto input frames. The majority of use cases should use the default values described in PreviewDetectionRegion.Builder.setDisplayRotation(int) and PreviewDetectionRegion.Builder.setCameraRotation(int). Apps using a display other than default or a camera source other than CameraHelper should provide rotation information via the relevant builder methods.

Apps using CameraHelper to stream the preview can access the percentage of visible camera frame by calling CameraHelper.getRectForVisibleSurface() within a CameraRegionListener.onVisibleRegionChanged() callback.

Nested Class Summary

Nested Classes

Modifier and Type	Class	Description
static class	PreviewDetectionRegion.Builder	The builder used to create PreviewDetectionRegion

Method Summary

Modifier and Type	Method	Description
static PreviewDetectionRegion.Builder	Builder(android.graphics.RectF visiblePreview)	Creates a Builder based on the visible region of the camera image.

Methods inherited from class com.digimarc.dms.readers.image.DetectionRegion

getBottom, getHeight, getLeft, getRect, getRight, getTop, getWidth

Methods inherited from class java.lang.Object

equals, getClass, hashCode, notify, notifyAll, toString, wait, wait, wait

Method Details

Builder

@NonNull
public static PreviewDetectionRegion.Builder Builder(@NonNull
 android.graphics.RectF visiblePreview)

Creates a Builder based on the visible region of the camera image.

Apps using CameraHelper to stream camera preview can use the value of CameraHelper.getRectForVisibleSurface() to restrict detection to the visible portion of the camera frame. Further restrictions can be set relative to the visible region with PreviewDetectionRegion.Builder.setRegionOfInterest(RectF).

Parameters:

visiblePreview - The percentage of the camera frame that should be used to define the detection region. The region is expected to be in normalized coordinates (0..1).

See also: CameraHelper.getRectForVisibleSurface()

Returns:

Builder for visible preview region