CoordinateTransform

Added in 1.1.0

Kotlin |Java

public final class CoordinateTransform

This class represents the transform from one OutputTransform to another.

This class can be used to map the coordinates of one OutputTransform to another, given that they are associated with the same ViewPort. OutputTransform can represent the output of a UseCase or PreviewView. For example, mapping the coordinates of detected objects from ImageAnalysis output to the drawing location in PreviewView.

// imageProxy the output of an ImageAnalysis.
OutputTransform source = ImageProxyTransformFactory().getOutputTransform(imageProxy);
OutputTransform target = previewView.getOutputTransform();

// Build the transform from ImageAnalysis to PreviewView
CoordinateTransform coordinateTransform = new CoordinateTransform(source, target);

// Detect face in ImageProxy and transform the coordinates to PreviewView.
// The value of faceBox can be used to highlight the face in PreviewView.
RectF faceBox = detectFaceInImageProxy(imageProxy);
coordinateTransform.mapRect(faceBox);

Summary

Public constructors
`CoordinateTransform( @NonNull OutputTransform source, @NonNull OutputTransform target )` Creates the transform between the `source` and the `target`.

Public methods
`void`	`mapPoint(@NonNull PointF point)` Apply this transform to the `PointF`, and write the transformed points back into the array
`void`	`mapPoints(@NonNull float[] points)` Apply this transform to the array of 2D points, and write the transformed points back into the array
`void`	`mapRect(@NonNull RectF rect)` Apply this transform to the rectangle, and write the transformed rectangle back into it.
`void`	`transform(@NonNull Matrix outMatrix)` Copies the current transform to the specified `Matrix`.

Public constructors

CoordinateTransform

Added in 1.1.0

public CoordinateTransform(
    @NonNull OutputTransform source,
    @NonNull OutputTransform target
)

Creates the transform between the source and the target.

The source and the target must be associated with the same ViewPort.

Parameters
`@NonNull OutputTransform source`	the source
`@NonNull OutputTransform target`	the target

See also
`UseCaseGroup`
`ViewPort`

Public methods

mapPoint

Added in 1.1.0

public void mapPoint(@NonNull PointF point)

Apply this transform to the PointF, and write the transformed points back into the array

Parameters
`@NonNull PointF point`	The point to transform.

mapPoints

Added in 1.1.0

public void mapPoints(@NonNull float[] points)

Apply this transform to the array of 2D points, and write the transformed points back into the array

Parameters
`@NonNull float[] points`	The array [x0, y0, x1, y1, ...] of points to transform.

See also
`mapPoints`

mapRect

Added in 1.1.0

public void mapRect(@NonNull RectF rect)

Apply this transform to the rectangle, and write the transformed rectangle back into it. This is accomplished by transforming the 4 corners of rect, and then setting it to the bounds of those points.

Parameters
`@NonNull RectF rect`	The rectangle to transform.

transform

Added in 1.1.0

public void transform(@NonNull Matrix outMatrix)

Copies the current transform to the specified Matrix.

Parameters
`@NonNull Matrix outMatrix`	a `android.graphics.Matrix` in which to copy the current transform.