Transition_EaseInElastic - ProGUI Reference Manual

Syntax

Value.d = Transition_EaseInElastic(t.d, b.d, c.d, d.d, amplitude.d=1, period.d=0.3)

Description

Calculates an intermediate value using an elastic easing curve that simulates an object overshooting and oscillating around the start value before moving towards the end value (ease-in).

Parameters

t.d
The current elapsed time of the animation in milliseconds.

b.d
The starting value of the property being animated.

c.d
The total change in value (target value - starting value).

d.d
The total duration of the animation in milliseconds.

amplitude.d (optional)
A factor controlling the amplitude (height) of the elastic oscillations. Default is 1.

period.d (optional)
Controls the frequency of the oscillations. Smaller values result in more oscillations. Default is 0.3.

Return Value

Returns the interpolated value (Double) at the current time `t` according to the ease-in elastic curve.

Example

IncludeFile "ProGUI_PB.pbi"

Structure MyAnimData
  TargetValue.d
  StartValue.d
  x.d
EndStructure

Procedure DrawHandler(Window, EventType, *EventData.PG_EventDraw, *UserData.MyAnimData)
  
    DrawClear(RGB(200, 200, 200), 1) ; Grey background

    ; Draw a box whose X position is animated
    DrawBox(*UserData\x, (*EventData\height / 2) - 25, 50, 50, RGB(0, 0, 255))
    
EndProcedure

Procedure AnimateHandler(Window, EventType, *EventData.PG_EventAnimate, *UserData.MyAnimData)
  
  Select *EventData\state
  
    Case #PG_Event_Animate_Start
      Debug "Animation started."
      
    Case #PG_Event_Animate_Update
      ; Calculate intermediate value using the ease-in-elastic transition
      *UserData\x = Transition_EaseInElastic(*EventData\currentTime, *UserData\StartValue, *UserData\TargetValue - *UserData\StartValue, *EventData\duration)
      ; Optional: *UserData\x = Transition_EaseInElastic(..., ..., ..., ..., 1.2, 0.2) ; Higher amplitude, more frequent oscillation
      WindowRedraw(Window)
      
    Case #PG_Event_Animate_End
      Debug "Animation ended"
      ; Ensure final value is set exactly
      *UserData\x = *UserData\TargetValue
      WindowRedraw(Window)
  EndSelect
EndProcedure

StartProGUI()

MyWindow = CreateWindow(0, 0, 300, 200, "Transition_EaseInElastic Example")

If MyWindow
    
  ; Setup data for animation
  *AnimData.MyAnimData = AllocateStructure(MyAnimData)
  *AnimData\StartValue = 10 
  *AnimData\TargetValue = 200
    
  AddEventHandler(MyWindow, #PG_Event_Draw, @DrawHandler(), *AnimData)
  AddEventHandler(MyWindow, #PG_Event_Animate, @AnimateHandler(), *AnimData) 

  ; Start a 2-second animation
  AnimID = StartAnimation(MyWindow, #PG_Any, 2000)

  WindowShow(MyWindow, #True, #PG_WindowShow_ScreenCentered)
  Repeat : Event = WaitWindowEvent() : Until Event = #PB_Event_CloseWindow
  
  StopAnimation(MyWindow, AnimID) 
  FreeStructure(*AnimData)
  
EndIf 

StopProGUI()

Supported OS

Windows, Linux