Transitions

MenuBuddy includes a transition system for animating screens as they appear and disappear. Transitions control the position and alpha of screens over time.

IScreenTransition Interface

public interface IScreenTransition
{
    float OnTime { get; set; }         // Duration (seconds) to transition on
    float OffTime { get; set; }        // Duration (seconds) to transition off
    float TransitionPosition { get; }  // Current position (0.0 = off, 1.0 = on)
    float Alpha { get; }              // Current alpha (0.0 = transparent, 1.0 = opaque)
    TransitionState State { get; set; }

    event EventHandler OnStateChange;

    Color AlphaColor(Color color);     // Apply alpha to a color
    void Restart(bool transitionOn);   // Restart the transition
    bool Update(GameClock gameTime, bool transitionOn); // Returns true if still transitioning
}

TransitionState Enum

State Description
Hidden Screen is not visible, transition is complete (off)
TransitionOn Screen is animating into view
Active Screen is fully visible
TransitionOff Screen is animating out of view

Transition Flow

Hidden ──► TransitionOn ──► Active ──► TransitionOff ──► Hidden
                                           │
                                           ▼
                                     (if exiting)
                                      Removed

When a screen is added, it transitions from Hidden to Active through TransitionOn. When a screen exits or is covered, it transitions from Active to Hidden through TransitionOff.

Configuring Transition Timing

public class MyScreen : WidgetScreen
{
    public MyScreen() : base("My Screen")
    {
        // Set transition durations (in seconds)
        Transition.OnTime = 0.5f;   // Half second to appear
        Transition.OffTime = 0.3f;  // 300ms to disappear
    }
}

TransitionWipeType Enum

Controls the direction of screen transitions.

Pop Transitions

Items enter and exit from the same direction:

Type Enter Exit
PopLeft Slides in from left Slides out to left
PopRight Slides in from right Slides out to right
PopTop Slides in from top Slides out to top
PopBottom Slides in from bottom Slides out to bottom

Slide Transitions

Items enter from one direction and exit to the opposite:

Type Enter Exit
SlideLeft Slides in from left Slides out to right
SlideRight Slides in from right Slides out to left
SlideTop Slides in from top Slides out to bottom
SlideBottom Slides in from bottom Slides out to top

No Transition

Type Behavior
None No movement or animation

Setting the Default Transition

Set the global default transition type in InitStyles():

protected override void InitStyles()
{
    base.InitStyles();
    StyleSheet.DefaultTransition = TransitionWipeType.SlideLeft;
}

Transition Objects

MenuBuddy provides several transition object types for animating individual elements:

BaseTransitionObject

The abstract base for all transition-aware objects.

PointTransitionObject

Animates a Point value between two positions over time.

PathTransitionObject

Animates an object along a defined path.

DirectionTransitionObject

Animates in a specific direction based on TransitionWipeType.

WipeTransitionObject

Implements the wipe-based transition effects (slide/pop).

Using Transitions with Alpha

The IScreenTransition.Alpha property provides the current opacity level during transitions. Use it to fade elements:

public override void Draw(GameTime gameTime)
{
    // Alpha is automatically applied to screen rendering
    // You can also use it manually:
    Color fadeColor = Transition.AlphaColor(Color.White);

    ScreenManager.SpriteBatchBegin();
    // Draw with fadeColor for manual alpha control
    ScreenManager.SpriteBatchEnd();
}

Background Fading

Screens can fade the background behind them during transitions:

public override void Draw(GameTime gameTime)
{
    // Fade background to 66% opacity
    FadeBackground();

    // Or with a custom alpha
    FadeBackground(0.8f);

    base.Draw(gameTime);
}

Next Steps