InProgressStroke

public final @NonNull Result<Unit> enqueueInputs(
    @NonNull StrokeInputBatch realInputs,
    @NonNull StrokeInputBatch predictedInputs
)

Enqueues the incremental realInputs and sets the prediction to predictedInputs, overwriting any previous prediction. Queued inputs will be processed on the next call to updateShape.

This method requires that:

• start has been previously called to set the current Brush.

• finishInput has not been called since the last call to start.

• realInputs and predictedInputs must form a valid stroke input sequence together with previously added real input.

If the above requirements are not satisfied, the Result will be a failure and this object is left in the state it had prior to the call.

Either one or both of realInputs and predictedInputs may be empty.

public final void finishInput()

Indicates that the inputs for the current stroke are finished. After calling this, it is an error to call enqueueInputs until start is called again to start a new stroke. This method is idempotent; it has no effect if start was never called, or if this method has already been called since the last call to start.

public final Brush getBrush()

The Brush currently being used to generate the stroke content. To set this, call start.

public final @IntRange(from = 0) int getBrushCoatCount()

Returns the number of BrushCoats for the current brush, or zero if start has not been called.

public final @IntRange(from = 0) int getInputCount()

Returns the number of StrokeInputs in the stroke so far. This counts all of the real inputs and the most-recently-processed sequence of predicted inputs.

public final boolean getNeedsUpdate()

Returns true if calling updateShape would have any effect on the stroke (and should thus be called before the next render), or false if no calls to updateShape are currently needed. Specifically:

• If the brush has one or more timed shape animation behavior that are still active (which can be true even after inputs are finished), returns true.

• If there are no active shape animation behaviors, but there are pending inputs from an enqueueInputs call that have not yet been consumed by a call to updateShape, returns true.

• Otherwise, returns false.

Once isInputFinished returns true and this method returns false, the stroke is considered "dry", and will not change any further until the next call to start.

public final @IntRange(from = 0) int getOutlineCount(@IntRange(from = 0) int coatIndex)

Returns the number of outlines for the specified brush coat.

Calls to functions that accept an outlineIndex must treat the result of this function as an upper bound. Coats with discontinuous geometry will always have multiple outlines, but even continuous geometry may be drawn with multiple overlapping outlines when this improves rendering quality or performance.

public final @IntRange(from = 0) int getOutlineVertexCount(
    @IntRange(from = 0) int coatIndex,
    @IntRange(from = 0) int outlineIndex
)

Returns the number of outline points for the specified outline and brush coat. populateOutlinePosition must treat the result of this as the upper bound of its outlineVertexIndex parameter.

public final @IntRange(from = 0) int getPredictedInputCount()

Returns the number of inputs in the current stroke prediction.

public final boolean isInputFinished()

Returns true if finishInput has been called since the last call to start, or if start hasn't been called yet. If this returns true, it is an error to call enqueueInputs.

public final @NonNull StrokeInput populateInput(@NonNull StrokeInput out, @IntRange(from = 0) int index)

Gets the value of the i-th input and overwrites out. Requires that index is positive and less than getInputCount.

public final @NonNull MutableStrokeInputBatch populateInputs(
    @NonNull MutableStrokeInputBatch out,
    @IntRange(from = 0) int from,
    @IntRange(from = 0) int to
)

Add the specified range of inputs from this stroke to the output MutableStrokeInputBatch.

public final @NonNull BoxAccumulator populateMeshBounds(
    @IntRange(from = 0) int coatIndex,
    @NonNull BoxAccumulator outBoxAccumulator
)

Writes to outBoxAccumulator the bounding box of the vertex positions of the mesh for brush coat coatIndex.

public final void populateOutlinePosition(
    @IntRange(from = 0) int coatIndex,
    @IntRange(from = 0) int outlineIndex,
    @IntRange(from = 0) int outlineVertexIndex,
    @NonNull MutableVec outPosition
)

Fills outPosition with the x- and y- coordinates of the specified outline vertex.

public final @NonNull BoxAccumulator populateUpdatedRegion(@NonNull BoxAccumulator outBoxAccumulator)

Returns the bounding rectangle of mesh positions added, modified, or removed by calls to updateShape since the most recent call to start or resetUpdatedRegion.

public final void resetUpdatedRegion()

Call after making use of a value from populateUpdatedRegion to reset the accumulation.

public final void start(@NonNull Brush brush)

Clears and starts a new stroke with the given brush.

This includes clearing or resetting any existing inputs, mesh data, and updated region. This method must be called at least once after construction before starting to call enqueueInputs or updateShape.

public final @NonNull Stroke toImmutable()

Copies the current input, brush, and geometry as of the last call to start or updateShape to a new Stroke.

The resulting Stroke will not be modified if further inputs are added to this InProgressStroke, and a Stroke created by another call to this method will not modify or be connected in any way to the prior Stroke.

public final @NonNull Result<Unit> updateShape(long currentElapsedTimeMillis)

Updates the stroke geometry up to the given duration since the start of the stroke. This will will consume any inputs queued up by calls to enqueueInputs, and cause brush shape animations (if any) to progress up to the specified time. Any stroke geometry resulting from previously-predicted input from before the previous call to this method will be cleared.

This method requires that:

• start has been previously called to set the current brush.

• The value of currentElapsedTimeMillis passed into this method over the course of a single stroke must be non-decreasing and non-negative. Its default value causes all ongoing stroke shape animations to be completed immediately. To have shape animations progress at their intended rate, pass in values for this field that are in the same time base as the StrokeInput.elapsedTimeMillis values being passed to enqueueInputs, repeatedly until isInputFinished returns true.

If the above requirements are not satisfied, the Result will be a failure and this object is left in the state it had prior to the call.