alpha.html

JAVA多媒体开发类库说明

 accepts the following values, INCREASING_ENABLE or
 DECREASING_ENABLE, which may be ORed together to specify
 that both are active.
 The increasing alpha parameters are increasingAlphaDuration,
 increasingAlphaRampDuration, and alphaAtOneDuration.
 The decreasing alpha parameters are decreasingAlphaDuration,
 decreasingAlphaRampDuration, and alphaAtZeroDuration.<DD><CODE>triggerTime</CODE> - time in milliseconds since the start time
 that this object first triggers<DD><CODE>phaseDelayDuration</CODE> - number of milliseconds to wait after
 triggerTime before actually starting this alpha<DD><CODE>increasingAlphaDuration</CODE> - period of time during which alpha goes
 from zero to one<DD><CODE>increasingAlphaRampDuration</CODE> - period of time during which
 the alpha step size increases at the beginning of the
 increasingAlphaDuration and, correspondingly, decreases at the end
 of the increasingAlphaDuration. This value is clamped to half of
 increasingAlphaDuration. NOTE: a value of zero means that the alpha
 step size remains constant during the entire increasingAlphaDuration.<DD><CODE>alphaAtOneDuration</CODE> - period of time that alpha stays at one<DD><CODE>decreasingAlphaDuration</CODE> - period of time during which alpha goes
 from one to zero<DD><CODE>decreasingAlphaRampDuration</CODE> - period of time during which
 the alpha step size increases at the beginning of the
 decreasingAlphaDuration and, correspondingly, decreases at the end
 of the decreasingAlphaDuration. This value is clamped to half of
 decreasingAlphaDuration. NOTE: a value of zero means that the alpha
 step size remains constant during the entire decreasingAlphaDuration.<DD><CODE>alphaAtZeroDuration</CODE> - period of time that alpha stays at zero</DL>
</DL>
<HR>

<A NAME="Alpha(int, long, long, long, long, long)"><!-- --></A><H3>
Alpha</H3>
<PRE>
public <B>Alpha</B>(int&nbsp;loopCount,
             long&nbsp;triggerTime,
             long&nbsp;phaseDelayDuration,
             long&nbsp;increasingAlphaDuration,
             long&nbsp;increasingAlphaRampDuration,
             long&nbsp;alphaAtOneDuration)</PRE>
<DL>
<DD>Constructs a new Alpha object that assumes that the mode is 
 INCREASING_ENABLE.
<P>
<DL>
<DT><B>Parameters:</B><DD><CODE>loopCount</CODE> - number of times to run this alpha; a value
 of -1 specifies that the alpha loops indefinitely.<DD><CODE>triggerTime</CODE> - time in milliseconds since the start time
 that this object first triggers<DD><CODE>phaseDelayDuration</CODE> - number of milliseconds to wait after
 triggerTime before actually starting this alpha<DD><CODE>increasingAlphaDuration</CODE> - period of time during which alpha goes
 from zero to one<DD><CODE>increasingAlphaRampDuration</CODE> - period of time during which
 the alpha step size increases at the beginning of the
 increasingAlphaDuration and, correspondingly, decreases at the end
 of the increasingAlphaDuration. This value is clamped to half of
 increasingAlphaDuration. NOTE: a value of zero means that the alpha
 step size remains constant during the entire increasingAlphaDuration.<DD><CODE>alphaAtOneDuration</CODE> - period of time that alpha stays at one</DL>
</DL>
<HR>

<A NAME="Alpha(int, long)"><!-- --></A><H3>
Alpha</H3>
<PRE>
public <B>Alpha</B>(int&nbsp;loopCount,
             long&nbsp;increasingAlphaDuration)</PRE>
<DL>
<DD>This constructor takes only the loopCount and increasingAlphaDuration
  as parameters and assigns the default values to all of the other
  parameters.
<P>
<DL>
<DT><B>Parameters:</B><DD><CODE>loopCount</CODE> - number of times to run this alpha; a value
 of -1 specifies that the alpha loops indefinitely<DD><CODE>increasingAlphaDuration</CODE> - period of time during which alpha goes
 from zero to one</DL>
</DL>

<!-- ============ METHOD DETAIL ========== -->

<A NAME="method_detail"><!-- --></A>
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<TR BGCOLOR="#CCCCFF" CLASS="TableHeadingColor">
<TH ALIGN="left" COLSPAN="1"><FONT SIZE="+2">
<B>Method Detail</B></FONT></TH>
</TR>
</TABLE>

<A NAME="pause()"><!-- --></A><H3>
pause</H3>
<PRE>
public void <B>pause</B>()</PRE>
<DL>
<DD>Pauses this alpha object.  The current system time when this
 method is called will be used in place of the actual current
 time when calculating subsequent alpha values.  This has the
 effect of freezing the interpolator at the time the method is
 called.
<P>
<DD><DL>
<DT><B>Since:</B></DT>
  <DD>Java 3D 1.3</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="pause(long)"><!-- --></A><H3>
pause</H3>
<PRE>
public void <B>pause</B>(long&nbsp;time)</PRE>
<DL>
<DD>Pauses this alpha object as of the specified time.  The specified
 time will be used in place of the actual current time when
 calculating subsequent alpha values.  This has the effect of freezing
 the interpolator at the specified time.  Note that specifying a
 time in the future (that is, a time greater than
 System.currentTimeMillis()) will cause the alpha to immediately
 advance to that point before pausing.  Similarly, specifying a
 time in the past (that is, a time less than
 System.currentTimeMillis()) will cause the alpha to immediately
 revert to that point before pausing.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>time</CODE> - the time at which to pause the alpha
<DT><B>Throws:</B>
<DD><CODE>java.lang.IllegalArgumentException</CODE> - if time <= 0<DT><B>Since:</B></DT>
  <DD>Java 3D 1.3</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="resume()"><!-- --></A><H3>
resume</H3>
<PRE>
public void <B>resume</B>()</PRE>
<DL>
<DD>Resumes this alpha object.  If the alpha
 object was paused, the difference between the current
 time and the pause time will be used to adjust the startTime of
 this alpha.  The equation is as follows:

 <ul>
 <code>startTime += System.currentTimeMillis() - pauseTime</code>
 </ul>

 Since the alpha object is no longer paused, this has the effect
 of resuming the interpolator as of the current time.  If the
 alpha object is not paused when this method is called, then this
 method does nothing--the start time is not adjusted in this case.
<P>
<DD><DL>
<DT><B>Since:</B></DT>
  <DD>Java 3D 1.3</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="resume(long)"><!-- --></A><H3>
resume</H3>
<PRE>
public void <B>resume</B>(long&nbsp;time)</PRE>
<DL>
<DD>Resumes this alpha object as of the specified time.  If the alpha
 object was paused, the difference between the specified
 time and the pause time will be used to adjust the startTime of
 this alpha.  The equation is as follows:

 <ul><code>startTime += time - pauseTime</code></ul>

 Since the alpha object is no longer paused, this has the effect
 of resuming the interpolator as of the specified time.  If the
 alpha object is not paused when this method is called, then this
 method does nothing--the start time is not adjusted in this case.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>time</CODE> - the time at which to resume the alpha
<DT><B>Throws:</B>
<DD><CODE>java.lang.IllegalArgumentException</CODE> - if time <= 0<DT><B>Since:</B></DT>
  <DD>Java 3D 1.3</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="isPaused()"><!-- --></A><H3>
isPaused</H3>
<PRE>
public boolean <B>isPaused</B>()</PRE>
<DL>
<DD>Returns true if this alpha object is paused.
<P>
<DD><DL>

<DT><B>Returns:</B><DD>true if this alpha object is paused, false otherwise<DT><B>Since:</B></DT>
  <DD>Java 3D 1.3</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="getPauseTime()"><!-- --></A><H3>
getPauseTime</H3>
<PRE>
public long <B>getPauseTime</B>()</PRE>
<DL>
<DD>Returns the time at which this alpha was paused.
<P>
<DD><DL>

<DT><B>Returns:</B><DD>the pause time; returns 0 if this alpha is not paused<DT><B>Since:</B></DT>
  <DD>Java 3D 1.3</DD>
</DL>
</DD>
</DL>
<HR>

<A NAME="value()"><!-- --></A><H3>
value</H3>
<PRE>
public float <B>value</B>()</PRE>
<DL>
<DD>This method returns a value between 0.0 and 1.0 inclusive,
 based on the current time and the time-to-alpha parameters
 established for this alpha.  If this alpha object is paused,
 the value will be based on the pause time rather than the
 current time.
 This method will return the starting alpha value if the alpha
 has not yet started (that is, if the current time is less
 than startTime + triggerTime + phaseDelayDuration). This
 method will return the ending alpha value if the alpha has
 finished (that is, if the loop count has expired).
<P>
<DD><DL>

<DT><B>Returns:</B><DD>a value between 0.0 and 1.0 based on the current time</DL>
</DD>
</DL>
<HR>

<A NAME="value(long)"><!-- --></A><H3>
value</H3>
<PRE>
public float <B>value</B>(long&nbsp;atTime)</PRE>
<DL>
<DD>This method returns a value between 0.0 and 1.0 inclusive,
 based on the specified time and the time-to-alpha parameters
 established for this alpha.
 This method will return the starting alpha value if the alpha
 has not yet started (that is, if the specified time is less
 than startTime + triggerTime + phaseDelayDuration). This
 method will return the ending alpha value if the alpha has
 finished (that is, if the loop count has expired).
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>atTime</CODE> - The time for which we wish to compute alpha
<DT><B>Returns:</B><DD>a value between 0.0 and 1.0 based on the specified time</DL>
</DD>
</DL>
<HR>

<A NAME="getStartTime()"><!-- --></A><H3>
getStartTime</H3>
<PRE>
public long <B>getStartTime</B>()</PRE>
<DL>
<DD>Retrieves this alpha's startTime, the base
 for all relative time specifications; the default value
 for startTime is the system start time.
<P>
<DD><DL>

<DT><B>Returns:</B><DD>this alpha's startTime.</DL>
</DD>
</DL>
<HR>

<A NAME="setStartTime(long)"><!-- --></A><H3>
setStartTime</H3>
<PRE>
public void <B>setStartTime</B>(long&nbsp;startTime)</PRE>
<DL>
<DD>Sets this alpha's startTime to that specified in the argument; 
 startTime sets the base (or zero) for all relative time
 computations; the default value for startTime is the system
 start time.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>startTime</CODE> - the new startTime value</DL>
</DD>
</DL>
<HR>

<A NAME="getLoopCount()"><!-- --></A><H3>
getLoopCount</H3>
<PRE>
public int <B>getLoopCount</B>()</PRE>
<DL>
<DD>Retrieves this alpha's loopCount.
<P>
<DD><DL>

<DT><B>Returns:</B><DD>this alpha's loopCount.</DL>
</DD>
</DL>
<HR>

<A NAME="setLoopCount(int)"><!-- --></A><H3>
setLoopCount</H3>
<PRE>
public void <B>setLoopCount</B>(int&nbsp;loopCount)</PRE>
<DL>
<DD>Set this alpha's loopCount to that specified in the argument.
<P>
<DD><DL>
<DT><B>Parameters:</B><DD><CODE>loopCount</CODE> - the new loopCount value</DL>
</DD>
</DL>
<HR>

<A NAME="getMode()"><!-- --></A><H3>
getMode</H3>
<PRE>
public int <B>getMode</B>()</PRE>
<DL>
<DD>Retrieves this alpha's mode.
<P>
<DD><DL>

<DT><B>Returns:</B><DD>this alpha's mode: any combination of
 INCREASING_ENABLE and DECREASING_ENABLE</DL>
</DD>
</DL>