Morph
public final class Morph
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 |
|---|
Morph(@NonNull RoundedPolygon start, @NonNull RoundedPolygon end) |
Public methods |
|
|---|---|
final @NonNull List<@NonNull Cubic> |
asCubics(float progress)Returns a representation of the morph object at a given |
final @NonNull float[] |
calculateBounds(@NonNull float[] bounds, boolean approximate)Calculates the axis-aligned bounds of the object. |
final @NonNull float[] |
calculateMaxBounds(@NonNull float[] bounds)Like |
final void |
forEachCubic(Returns a representation of the morph object at a given |
Public constructors
Public methods
asCubics
public final @NonNull List<@NonNull Cubic> asCubics(float progress)
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 | |
|---|---|
float progress |
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
public final @NonNull float[] calculateBounds(@NonNull float[] bounds, boolean approximate)
Calculates the axis-aligned bounds of the object.
| Parameters | |
|---|---|
@NonNull float[] bounds |
a buffer to hold the results. If not supplied, a temporary buffer will be created. |
boolean approximate |
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 | |
|---|---|
@NonNull float[] |
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
public final @NonNull float[] calculateMaxBounds(@NonNull float[] bounds)
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 | |
|---|---|
@NonNull float[] bounds |
a buffer to hold the results. If not supplied, a temporary buffer will be created. |
| Returns | |
|---|---|
@NonNull float[] |
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
public final void forEachCubic(
float progress,
@NonNull MutableCubic mutableCubic,
@NonNull Function1<@NonNull MutableCubic, Unit> callback
)
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 | |
|---|---|
float progress |
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). |
@NonNull MutableCubic mutableCubic |
An instance of |
@NonNull Function1<@NonNull MutableCubic, Unit> callback |
The function to be called for each Cubic |