Scroller

The Scroller is based on the Android Open Source Project's Scroller. It makes it easy to move something from point A to point B in way that's cleaner and more robust than simple lerping.

Usage

Download Link

The Scroller class is not a MonoBehavior, it cannot be attached to a GameObject, it can only be created within another class.

Create it using this structure:

Correct

#!c#
using UnityEngine;
using UnityEngine.UI.ScrollSnaps;

public class TestScript : MonoBehaviour {

    Scroller m_Scroller;

    public void Start()
    {
        m_Scroller = new Scroller();
    }
}

Scrollers cannot be created in instance field initializers, such as below, because of how they access the screen's dpi.

Incorrect

#!c#
using UnityEngine;
using UnityEngine.UI.ScrollSnaps;

public class TestScript : MonoBehaviour {

    Scroller m_Scroller = new Scroller();
}

Available Constructors:

Scroller()

Scroller(float friction)

Scroller(Interpolator interpolator)

Scroller(int minDuration, int maxDuration)

Scroller(float friction, Interpolator interpolator)

Scroller(float friction, int minDuration, int maxDuration)

Scroller(int minDuration, int maxDuration, Interpolator interpolator)

Scroller(float friction, int minDuration, int maxDuration, Interpolator interpolator)

Dependencies:

None

Properties

Propert	Type	Description
interpolator	readonly Interpolator	Returns the scroller's interpolator. The interpolator modifies how scrolling is animated.
friction	readonly float	Returns the scroller's friction. The friction controls how quickly or slowly fling animations come to a stop.
minDuration	readonly int	Returns the minimum duration, in miliseconds, for all animations, scroll and fling.
maxDuraiton	readonly int	Returns the maximum duration, in miliseconds, for all animations, scroll and fling.
currentPosition	readonly Vector2	Returns the current position in the scroll. Before calling this it is best to call ComputeScrollOffset() if you are looking for up-to-date data.
startPosition	readonly Vector2	Returns the start position of the scroll.
finalPosition	readonly Vector2	Returns the final position of the scroll.
durationOfLatestAnimation	readonly int	Returns the total duration of the latest animation.
timePassedSinceStartOfAnimation	readonly int	Returns the amount of time since the start of the latest animation.
currentVelocity	readonly float	Returns the current velocity of the scroll.
isFinished	readonly bool	Returns if the latest animation is finished.
isFlinging	readonly bool	Returns if true if the scroller is currently animating a fling.
isScrolling	readonly bool	Returns true if the scroller is currently animating a scroll.

Public Functions

Type	Function
void	SetFinalX(int newX)
	Set the final position on the X axis, of the current animation.
void	SetFinalY(int newY)
	Set the final position on the Y axis, of the current animation.
void	SetFinalPosition(Vector2 newPos)
	Set the final position of the current animation.
void	ShiftAnimation(Vector2 offset)
	Shifts the start and end positions of the animation by the offset, does not affect the duration or speed.
void	ExtendDuration(int extendMS)
	Extend the scroll animation. This allows the running animation to scroll further and longer in combination with SetFinalPosition().
bool	ComputeScrollOffset()
	Call this when you want to know the new location. Returns true if the animation is not done yet.
void	StartScroll(Vector2 startPos, Vector2 endPos)
	Start scrolling by providing a start position and an end position, the duration will be the default value of 250 milliseconds.
void	StartScroll(Vector2 startPos, Vector2 endPos, int duration)
	Start scrolling by providing a start position, an end position, and the duration of the scroll in milliseconds.
void	StartScroll(int startX, int startY, int dx, int dy, int duration)
	Start scrolling by providing a start position, the movement delta, and the duration of the scroll in milliseconds.
void	Fling(Vector2 startPos, Vector2 velocity)
	Start scrolling based on a velocity. The distance traveled will depend on the velocity.
void	Fling(Vector2 startPos, Vector2 velocity, Vector2 minPos, Vector2 maxPos)
	Start scrolling based on a velocity. The distance traveled will depend on the velocity.
void	Fling(int startX, int startY, int velocityX, int velocityY, int minX, int minY, int maxX, int maxY)
	Start scrolling based on velocity. THe distance traveled will depend on the velocity.
void	ForceFinish()
	Stops the animation. Contrary to AbortAnimation() force finishing the animation does not move the scroller to the final position.
void	AbortAnimation()
	Stops the animation. Contrary to ForceFinish() aborting the animation moves the scroller to the final position.

Interpolators

Interpolators are used by the Scroller to modify how scrolling animations animate. The Scroller comes with 9 built-in interpolators, but you can also create your own. Simply impliment the Interpolator interface.

#!c#

public interface Interpolator
{
    float GetInterpolation(float input);
}

Here is a simple example of an interpolator, this one is provided with the Scroller script.

#!c#

public class AccelerateInterpolator : Interpolator {

    public float GetInterpolation(float input)
    {
        return input * input;
    }
}

Built-In Interpolators

Viscous FluidI nterpolator

Accelerate Decelerate Interpolator

Accelerate Interpolator

Anticipate Interpolator

Anticipate Overshoot Interpolator

Bounce Interpolator

Decelerate Interpolator

Linear Interpolator

Overshoot Interpolator

For a visual example of the interpolators see the Directional Scroll Snap Example Project.

Wiki

UnityUIScrollSnaps / HelperClasses / Scroller

Scroller

Contents

Usage

Properties

Public Functions

Interpolators