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IUIAnimationInterpolator::InterpolateValue method

Interpolates the value of an animation variable at the specified offset.

Syntax

C++


HRESULT InterpolateValue(
  [in]  UI_ANIMATION_SECONDS offset,
  [out] DOUBLE               *value
);

Parameters

offset [in]

The offset from the start of the transition.

This parameter is always greater than or equal to zero and less than the duration of the transition. This method is not called if the duration of the transition is zero.

value [out]

The interpolated value.

Return value

If the method succeeds, it returns S_OK. Otherwise, it returns an HRESULT error code. See Windows Animation Error Codes for a list of error codes.

Remarks

Windows Animation always calls the SetInitialValueAndVelocity method to set the initial value and velocity before calling InterpolateValue, so a custom interpolator need not check whether the initial value and velocity have been set.

Windows Animation can call SetInitialValueAndVelocity multiple times with different parameters. Interpolators can cache internal state to improve performance, but they must update this cached state each time SetInitialValueAndVelocity is called and ensure that the results of subsequent calls to InterpolateValue reflect the updated state.

Requirements

Minimum supported client	Windows 7, Windows Vista and Platform Update for Windows Vista [desktop apps \| Windows Store apps]
Minimum supported server	None supported
Header	UIAnimation.h
IDL	UIAnimation.idl
DLL	UIAnimation.dll