This class is used to animate between start and end polygons objects.

Morphing between arbitrary objects can be problematic because it can be difficult to determine how the points of a given shape map to the points of some other shape. Morph simplifies the problem by only operating on RoundedPolygon objects, which are known to have similar, contiguous structures. For one thing, the shape of a polygon is contiguous from start to end (compared to an arbitrary Path object, which could have one or more moveTo operations in the shape). Also, all edges of a polygon shape are represented by Cubic objects, thus the start and end shapes use similar operations. Two Polygon shapes then only differ in the quantity and placement of their curves. The morph works by determining how to map the curves of the two shapes together (based on proximity and other information, such as distance to polygon vertices and concavity), and splitting curves when the shapes do not have the same number of curves or when the curve placement within the shapes is very different.

Summary

Public constructors

Cmn

Public functions

List<Cubic>
asCubics(progress: Float)

Returns a representation of the morph object at a given progress value as a list of Cubics.

Cmn
FloatArray
calculateBounds(bounds: FloatArray, approximate: Boolean)

Calculates the axis-aligned bounds of the object.

Cmn
FloatArray

Like calculateBounds, this function calculates the axis-aligned bounds of the object and returns that rectangle.

Cmn
inline Unit
forEachCubic(
    progress: Float,
    mutableCubic: MutableCubic,
    callback: (MutableCubic) -> Unit
)

Returns a representation of the morph object at a given progress value, iterating over the cubics and calling the callback.

Cmn

Extension functions

Path
@ExperimentalMaterial3ExpressiveApi
Morph.toPath(progress: Float, path: Path, startAngle: Int)

Returns a Path for this Morph.

Cmn
Path
Morph.toPath(progress: Float, path: Path)
android

Public constructors

Morph

Morph(start: RoundedPolygon, end: RoundedPolygon)

Public functions

asCubics

fun asCubics(progress: Float): List<Cubic>

Returns a representation of the morph object at a given progress value as a list of Cubics. Note that this function causes a new list to be created and populated, so there is some overhead.

Parameters
progress: Float

a value from 0 to 1 that determines the morph's current shape, between the start and end shapes provided at construction time. A value of 0 results in the start shape, a value of 1 results in the end shape, and any value in between results in a shape which is a linear interpolation between those two shapes. The range is generally 0..1 and values outside could result in undefined shapes, but values close to (but outside) the range can be used to get an exaggerated effect (e.g., for a bounce or overshoot animation).

calculateBounds

fun calculateBounds(
    bounds: FloatArray = FloatArray(4),
    approximate: Boolean = true
): FloatArray

Calculates the axis-aligned bounds of the object.

Parameters
bounds: FloatArray = FloatArray(4)

a buffer to hold the results. If not supplied, a temporary buffer will be created.

approximate: Boolean = true

when true, uses a faster calculation to create the bounding box based on the min/max values of all anchor and control points that make up the shape. Default value is true.

Returns
FloatArray

The axis-aligned bounding box for this object, where the rectangles left, top, right, and bottom values will be stored in entries 0, 1, 2, and 3, in that order.

calculateMaxBounds

fun calculateMaxBounds(bounds: FloatArray = FloatArray(4)): FloatArray

Like calculateBounds, this function calculates the axis-aligned bounds of the object and returns that rectangle. But this function determines the max dimension of the shape (by calculating the distance from its center to the start and midpoint of each curve) and returns a square which can be used to hold the object in any rotation. This function can be used, for example, to calculate the max size of a UI element meant to hold this shape in any rotation.

Parameters
bounds: FloatArray = FloatArray(4)

a buffer to hold the results. If not supplied, a temporary buffer will be created.

Returns
FloatArray

The axis-aligned max bounding box for this object, where the rectangles left, top, right, and bottom values will be stored in entries 0, 1, 2, and 3, in that order.

forEachCubic

inline fun forEachCubic(
    progress: Float,
    mutableCubic: MutableCubic = MutableCubic(),
    callback: (MutableCubic) -> Unit
): Unit

Returns a representation of the morph object at a given progress value, iterating over the cubics and calling the callback. This function is faster than asCubics, since it doesn't allocate new Cubic instances, but to do this it reuses the same MutableCubic instance during iteration.

Parameters
progress: Float

a value from 0 to 1 that determines the morph's current shape, between the start and end shapes provided at construction time. A value of 0 results in the start shape, a value of 1 results in the end shape, and any value in between results in a shape which is a linear interpolation between those two shapes. The range is generally 0..1 and values outside could result in undefined shapes, but values close to (but outside) the range can be used to get an exaggerated effect (e.g., for a bounce or overshoot animation).

mutableCubic: MutableCubic = MutableCubic()

An instance of MutableCubic that will be used to set each cubic in time.

callback: (MutableCubic) -> Unit

The function to be called for each Cubic

Extension functions

@ExperimentalMaterial3ExpressiveApi
fun Morph.toPath(progress: Float, path: Path = Path(), startAngle: Int = 0): Path

Returns a Path for this Morph.

Parameters
progress: Float

the Morph's progress

path: Path = Path()

a Path to rewind and set with the new path data. In case provided, this Path would be the returned one.

startAngle: Int = 0

the angle (in degrees) from which to begin drawing the generated path. By default, it is set to 0 degrees, meaning the Path begins drawing at the 3 o'clock position.

fun Morph.toPath(progress: Float, path: Path = Path()): Path