IUIAnimationInterpolator::InterpolateValue method (uianimation.h)

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

Syntax

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

Parameters

[in] offset

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.

[out] value

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

See also

IUIAnimationInterpolator

UI_ANIMATION_SECONDS