Use the By property when you want to animate a value "by" a certain amount, rather than specifying a starting or ending value. You may also use the By property with the From property.
The following table summarizes how the From, To, and By properties may be used together or separately to determine an animation's target values.
[table style="1"]
| Properties specified | Resulting behavior |
|---|---|
| From | The animation progresses from the value specified by the From property to the base value of the property being animated or to a previous animation's output value, depending on how the previous animation is configured. |
| From and To | The animation progresses from the value specified by the From property to the value specified by the To property. |
| From and By | The animation progresses from the value specified by the From property to the value specified by the sum of the From and By properties. |
| To | The animation progresses from the animated property's base value or a previous animation's output value to the value specified by the To property. |
| By | The animation progresses from the base value of the property being animated or a previous animation's output value to the sum of that value and the value specified by the By property. |
[/table]
[note color='FFFF66'] If you set both the To and By properties, the To property takes precedence and the By property is ignored. [/note]
To use other interpolation methods or animate between more than two target values, use a DoubleAnimationUsingKeyFrames object.
