XAML in a Nutshell

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Chapter 11: Animations and Transformations

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Copyright © 2008 O’Reilly & Associates, Inc. All rights reserved.

<SplineThicknessKeyFrame.KeySpline>

<KeySpline ControlPoint1="5,5" ControlPoint2="10,10" />

</SplineThicknessKeyFrame.KeySpline>

</SplineThicknessKeyFrame>

All three ThicknessKeyFrame subclasses determine when (KeyTime) the frame will reach

the designated value (

Value). KeyTime is specified in terms of hours:minutes:seconds.

The

Value attribute of all ThicknessKeyFrame subclasses is a Thickness.

DiscreteThicknessKeyFrame

Skips from one value to the desired value without interpolation. Thus, the Value

will not be reached until KeyTime (relative to the beginning of the animation).

LinearThicknessKeyFrame

Utilizes linear interpolation to reach the desired value. Linear interpolation

progresses the animation at a steady rate for its duration.

SplineThicknessKeyFrame

Uses a concept similar to Bezier curves to interpolate values until Value has been

reached. This subclass requires an additional attribute,

KeySpline, which is used

to interpolate the value in much the same way as control points are used to inter-

polate a line when declaring a Bezier curve.

The

Thickness value may be specified using abbreviated markup syntax or explicitly

declared as a

Thickness element.

Attributes

KeySpline (required) (SplineThicknessKeyFrame only)

This

KeySpline describes how the key frame will be altered during animation.

KeyTime (required)

This attribute specifies when, relative to the animation, this key frame takes place:

• A time period specified in hours:minutes:seconds.

•

Uniform: The Duration will be split evenly among all key frames.

• Paced: The Duration will be split among key frames in a way that ensures the

speed of the animation remains relatively constant.

• A percentage of the total duration.

Value (required)

This

Thickness describes the destination value of the key frame.

Timeline

Hierarchy: DependencyObject ➝ Freezable ➝ Animatable

<Timeline

AccelerationRatio="1"

AutoReverse="true|false"

BeginTime="100"

CutOffTime="300"

FillBehavior="Deactivate|HoldEnd"

DecelerationRatio="1"

Duration="Automatic|Forever|100"

RepeatBehavior="IterationCount|RepeatDuration|Forever"

SpeedRatio="0.5" />

Timeline | 231

Animating

Elements

This is the Title of the Book, eMatter Edition

Copyright © 2008 O’Reilly & Associates, Inc. All rights reserved.

<Timeline .../> is an abstract element that represents a time period. Timeline makes

use of the

TimeSpan structure, which is represented textually as “d:h:s,” where “d” is

the number of days, “h” is the number of hours, and “s” is the number of seconds.

Attributes

AccelerationRatio (optional)

This

Double value represents the percentage of the Duration spent accelerating

from zero to its maximum rate. This attribute must be set to a value between 0

and 1, inclusive. The default value is 0.

AutoReverse (optional)

This

Boolean value determines whether the timeline will play in reverse after it has

completed a forward iteration.

true

The timeline will play in reverse at the end of each forward iteration.

false

The timeline will not play in reverse. This is the default value.

BeginTime (optional)

This

TimeSpan attribute determines when the timeline will begin. The default

value is 0.

CutOffTime (optional)

This

TimeSpan attribute determines when the timeline should end, relative to

BeginTime.

DecelerationRatio (optional)

This

Double value represents the percentage of the Duration spent decelerating

from its maximum rate to zero. This attribute must be set to a value between 0

and 1, inclusive. The default value is 0.

Duration (optional)

This attribute determines how long the timeline should continue, not counting

repetitions.

Automatic

The timeline automatically ends when its last child stops playing.

Forever

The timeline will continue playing indefinitely.

TimeSpan

The value of this attribute is a time span.

FillBehavior (optional)

This value determines how the animation will behave once it has completed but

while its parent is still active.

Deactivate

The Timeline is turned off when its parent is no longer active.

HoldEnd

The Timeline holds its progress until the end of its parent’s active and hold

periods.

RepeatBehavior (optional)

This attribute determines how the timeline will repeat its

Duration, if at all.