# Set up height animation

With height animation, an object’s height changes based on a tag value or the result of an expression. The height of the object is proportional to the value of the expression. For example, if the value of the expression is halfway between the minimum and maximum values, the object’s height will be halfway between its minimum and maximum vertical change percents.

Height animation is available for all drawing objects except image and panel objects, which only support visibility animation.

## To set up height animation for an object

1. Select the object.
2. Choose Height from the Animation menu or click the Height tab in the Animation dialog box.
3. Select a tag or create an expression that will evaluate to a number at run time to determine the height of the object.
4. Specify minimum and maximum values for vertical change (height) percent. You can also use the Object Smart Path feature to set these values.
5. Select the anchor for the object. The object will increase and decrease in height from this point.
6. Select the method to use to calculate the expression's minimum and maximum values.
7. Specify a range of values for the expression.

   Tip: | You can use the Object Explorer to search for objects in your display that have animation. Open the Highlight Settings box and select the kind of animation you want to highlight.

## Options

- Expression

  Type a tag name or an expression that will evaluate to numeric values at run time. An expression is a mathematical or logical equation that returns a value. It can contain tag names, constants and mathematical, relational, logical and/or bitwise operators. A tag name can be used as an expression. When you do this, the minimum and maximum expression values default to the tag's minimum and maximum values.

- Expression range
  - Use tag's min and max property values

    If you have specified a tag in the Expression box, click this button to use the tag's minimum and maximum values to define the range of values for the expression. If your expression contains more than one tag, the minimum and maximum values for the first tag will be used for the animation.

  - Use constant

    To use constant numeric values to define a range of values, click this button and specify values for minimum and maximum.

  - Read from tags

    To define the range of values using one tag's value for the minimum and another tag's value for the maximum, click this button and then specify a tag for minimum and another for maximum. Using this option, when the display opens and animation for an object is started, the tags' values are read once to set the minimum and maximum values. The tags are not read again after the display is opened, nor are the minimum and maximum values for the animation changed, even if the tag values change.

- Vertical Change (Percent)
  - At Minimum

    The height of an object when it is selected is the base size (100 percent). Click on a handle on the left or right side of the object and drag it to resize the object.

    or

    Type the height the object is to be when the expression evaluates to its minimum value. This is a percentage of its base size.

  - At Maximum

    Click on a handle on the left or right side of the object and drag it to resize the object.

    or

    Type the height the object is to be when the expression evaluates to its maximum value. This is a percentage of its base size.

- Anchor

  Anchor determines which part of the object remains constant.

  - Top

    Select Top if the top position of the object is to remain constant. As the value of the expression changes, the object grows to or shrinks from the bottom.

  - Middle

    Select Middle if the midpoint of the object is to remain constant. As the value of the expression changes, the object lengthens and shortens equally on either side of its midpoint.

  - Bottom

    Select Bottom if the bottom position of the object is to remain constant. As the value of the expression changes, the object grows to or shrinks from the top.

## See also

Attach animation to graphic objects

Tag names with animation

Use the Expression editor

Drawing objects

Object Smart Path

Object Explorer

Highlight Settings dialog box