extending the api.htm

是一部关于java高级图像处理的的一本入门书

  operation's property management. 
  <P>Each family of the image operation in JAI must have a descriptor that 
  implements this interface. The following basic resource data must be provided: 

  <P>
  <UL>
    <LI>GlobalName - a global operation name that is visible to all and is the 
    same in all <CODE>Locale</CODE>s
    <P></P></LI></UL>
  <UL>
    <LI>LocalName - a localized operation name that may be used as a synonym for 
    the global operation name
    <P></P></LI></UL>
  <UL>
    <LI>Vendor - the name of the vendor (company name) defining this operation
    <P></P></LI></UL>
  <UL>
    <LI>Description - a brief description of this operation
    <P></P></LI></UL>
  <UL>
    <LI>DocURL - a URL where additional documentation on this operation may be 
    found (the javadoc for the operation)
    <P></P></LI></UL>
  <UL>
    <LI>Version - the version of the operation
    <P></P></LI></UL>
  <UL>
    <LI>arg0Desc, arg1Desc, etc. - descriptions of the arguments. There must be 
    a property for each argument.
    <P></P></LI></UL>
  <UL>
    <LI>hint0Desc, hint1Desc, etc. - descriptions of the rendering hints. There 
    must be a property for each hint.
    <P></P></LI></UL>Additional information about the operation must be provided 
  when appropriate. It is also good idea to provide a detailed description of 
  the operation's functionality in the class comment. When all of the above data 
  is provided, the operation can be added to an <CODE>OperationRegistry</CODE>. 
  <P><A 
  href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Extension.doc.html#58545">Listing 
  14-2</A> shows an example of an operation descriptor for the Clamp operation. 
  Note that the descriptor also contains descriptions of the two required 
  operation parameters, but no hints as these aren't required for the operation.
  <P><CAPTION><FONT size=-1><B><A name=58545>
  <CENTER><FONT size=-1><B><I>Listing 14-2 </I><IMG 
  src="Extending the API.files/sm-blank.gif" border=0> Operation Descriptor for 
  Clamp Operation</B></FONT></CENTER></A>
  <P></B></FONT></CAPTION>
  <HR>
  <TR valign="top"><TD rowspan="16" colspan="1"><PRE>     public class ClampDescriptor extends OperationDescriptorImpl {
     /**
     * The resource strings that provide the general documentation
     * and specify the parameter list for this operation.
     */
     private static final String[][] resources = {
         {"GlobalName",  "Clamp"},
         {"LocalName",   "Clamp"},
         {"Vendor",      "com.sun.javax.media.jai"},
         {"Description", "Clamps the pixel values of a rendered image"},
         {"DocURL",      "http://java.sun.com/products/java-media/jai/
forDevelopers/jaiapi/
javax.media.jai.operator.ClampDescriptor.html"},
         {"Version",     "Beta")},
         {"arg0Desc",    "The lower boundary for each band."},
         {"arg1Desc",    "The upper boundary for each band."}
     };
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR 
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  <HR>

  <P>As described in <A 
  href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Programming-environ.doc.html#55910">Section 
  3.3, "Processing Graphs</A>," JAI has two image modes: Rendered and 
  Renderable. An operation supporting the Rendered mode takes 
  <CODE>RenderedImages</CODE> as its sources, can only be used in a Rendered op 
  chain, and produces a <CODE>RenderedImage</CODE>. An operation supporting the 
  Renderable mode takes <CODE>RenderableImage</CODE>s as its sources, can only 
  be used in a Renderable op chain, and produces a <CODE>RenderableImage</CODE>. 
  Therefore, the class types of the sources and the destination of an operation 
  are different between the two modes, but the parameters must be the same for 
  both modes. 
  <P>All operations must support the rendered mode and implement those methods 
  that supply the information for this mode. Those operations that support the 
  renderable mode must specify this feature using the 
  <CODE>isRenderableSupported</CODE> method and implement those methods that 
  supply the additional information for the Renderable mode. 
  <P><A 
  href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Extension.doc.html#58685">Table 
  14-2</A> lists the Rendered mode methods. <A 
  href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Extension.doc.html#58718">Table 
  14-3</A> lists the Renderable mode methods. <A 
  href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Extension.doc.html#58876">Table 
  14-4</A> lists the methods relative to operation parameters.
  <P>
  <TABLE cellPadding=3 border=3>
    <CAPTION><FONT size=-1><B><A name=58685><I>Table 14-2 </I><IMG 
    src="Extending the API.files/sm-blank.gif" border=0> Rendered Mode Methods 
    </A></B></FONT></CAPTION>
    <TBODY>
    <TR vAlign=top>
      <TH><A name=58689>Method </A>
      <TH><A name=58691>Description </A>
    <TR vAlign=top>
      <TD><A name=58693>isRenderedSupported</A><BR>
      <TD><A name=58695>Returns true if the operation supports the Rendered 
        image mode. This must be true for all operations.</A><BR>
    <TR vAlign=top>
      <TD><A name=58697>isImmediate</A><BR>
      <TD><A name=58749>Returns true if the operation should be rendered 
        immediately during the call to JAI.create; that is, the operation is 
        placed in immediate mode.</A><BR>
    <TR vAlign=top>
      <TD><A name=58701>getSourceClasses</A><BR>
      <TD><A name=58760>Returns an array of Classes that describe the types of 
        sources required by this operation in the Rendered image mode.</A><BR>
    <TR vAlign=top>
      <TD><A name=58705>getDestClass</A><BR>
      <TD><A name=58771>Returns a Class that describes the type of destination 
        this operation produces in the Rendered image mode.</A><BR>
    <TR vAlign=top>
      <TD><A name=58709>validateArguments</A><BR>
      <TD><A name=58785>Returns true if this operation is capable of handling 
        the input rendered source(s) and/or parameter(s) specified in the 
        ParameterBlock.</A><BR></TR></TBODY></TABLE>
  <P>
  <TABLE cellPadding=3 border=3>
    <CAPTION><FONT size=-1><B><A name=58718><I>Table 14-3 </I><IMG 
    src="Extending the API.files/sm-blank.gif" border=0> Renderable Mode Methods 
    </A></B></FONT></CAPTION>
    <TBODY>
    <TR vAlign=top>
      <TH><A name=58722>Method </A>
      <TH><A name=58724>Description </A>
    <TR vAlign=top>
      <TD><A name=58726>isRenderableSupported</A><BR>
      <TD><A name=58811>Returns true if the operation supports the Renderable 
        image mode.</A><BR>
    <TR vAlign=top>
      <TD><A name=58801>getRenderableSourceClasses</A><BR>
      <TD><A name=58836>Returns an array of Classes that describe the types of 
        sources required by this operation in the Renderable image mode.</A><BR>
    <TR vAlign=top>
      <TD><A name=58803>getRenderableDestClass</A><BR>
      <TD><A name=58847>Returns a Class that describes the type of destination 
        this operation produces in the Renderable image mode.</A><BR>
    <TR vAlign=top>
      <TD><A name=58738>validateRenderableArguments</A><BR>
      <TD><A name=58861>Returns true if this operation is capable of handling 
        the input Renderable source(s) and/or parameter(s) specified in the 
        ParameterBlock.</A><BR></TR></TBODY></TABLE>
  <P>
  <TABLE cellPadding=3 border=3>
    <CAPTION><FONT size=-1><B><A name=58876><I>Table 14-4 </I><IMG 
    src="Extending the API.files/sm-blank.gif" border=0> Parameter Methods 
    </A></B></FONT></CAPTION>
    <TBODY>
    <TR vAlign=top>
      <TH><A name=58880>Method </A>
      <TH><A name=58882>Description </A>
    <TR vAlign=top>
      <TD><A name=58884>getNumParameters</A><BR>
      <TD><A name=58924>Returns the number of parameters (not including the 
        sources) required by this operation.</A><BR>
    <TR vAlign=top>
      <TD><A name=58888>getParamClasses</A><BR>
      <TD><A name=58935>Returns an array of Classes that describe the types of 
        parameters required by this operation.</A><BR>
    <TR vAlign=top>
      <TD><A name=58892>getParamNames</A><BR>
      <TD><A name=58946>Returns an array of Strings that are the localized 
        parameter names of this operation.</A><BR>
    <TR vAlign=top>
      <TD><A name=58896>getParamDefaults</A><BR>
      <TD><A name=58957>Returns an array of Objects that define the default 
        values of the parameters for this operation.</A><BR>
    <TR vAlign=top>
      <TD><A name=58900>getParamDefaultValue</A><BR>
      <TD><A name=58902>Returns the default value of a specified 
        parameter.</A><BR>
    <TR vAlign=top>
      <TD><A name=58904>getParamMinValue</A><BR>
      <TD><A name=58972>Returns the minimum legal value of a specified numeric 
        parameter for this operation.</A><BR>
    <TR vAlign=top>
      <TD><A name=58908>getParamMaxValue</A><BR>
      <TD><A name=58979>Returns the maximum legal value of a specified numeric 
        parameter for this operation.</A><BR></TR></TBODY></TABLE>
  <P>
  <TABLE border=0>
    <TBODY>
    <TR>
      <TD><IMG src="Extending the API.files/cistine.gif"></TD>
      <TD>
        <HR>
        <B>API:</B> <CODE>javax.media.jai.OperationRegistry </CODE>
        <HR>
      </TD></TR></TBODY></TABLE><PRE><UL>
<LI>void registerOperationDescriptor(OperationDescriptor odesc, 
       String operationName)
<P></P></LI></UL></PRE>
  <DL><A name=54658>
    <DT>
    <DD>registers an <CODE>OperationDescriptor</CODE> with the registry. Each 
    operation must have an <CODE>OperationDescriptor</CODE> before 
    <CODE>registerRIF()</CODE> may be called to add RIFs to the operation.
    <P>
    <TABLE cellPadding=3 border=3>
      <CAPTION><FONT size=-1><B></B></FONT></CAPTION>
      <TBODY>
      <TR vAlign=top>
        <TD rowSpan=2><EM>Parameter</EM>: 
          <P></P>
        <TD><CODE>odesc</CODE> 
          <P></P>
        <TD>An <CODE>OperationDescriptor</CODE> containing information about 
          the operation. 
          <P></P>
      <TR vAlign=top>
        <TD><CODE>operationName</CODE> 
          <P></P>
        <TD>The operation name as a <CODE>String</CODE>. 
          <P></P></TR></TBODY></TABLE></A>
    <P><A name=54665></P>
    <DT>
    <DD>A <CODE>OperationDescriptor</CODE> cannot be registered under an 
    operation name under which another <CODE>OperationDescriptor</CODE> was 
    registered previously. If such an attempt is made, an Error will be thrown. 
    </A>
    <P></P></DD></DL><PRE><UL>
<LI>void registerOperationByName(String odescClassName, 
       String  operationName)
<P></P></LI></UL></PRE>
  <DL><A name=54612>
    <DT>
    <DD>registers an <CODE>OperationDescriptor</CODE> by its class name.
    <P>
    <TABLE cellPadding=3 border=3>
      <CAPTION><FONT size=-1><B></B></FONT></CAPTION>
      <TBODY>
      <TR vAlign=top>
        <TD rowSpan=2><EM>Parameter</EM>:<EM></EM> 
          <P></P>
        <TD><CODE>odescClassName</CODE> 
          <P></P>
        <TD>The fully-qualified class name of the 
          <CODE>OperationDescriptor</CODE>. 
          <P></P>
      <TR vAlign=top>
        <TD><CODE>operationName</CODE> 
          <P></P>
        <TD>The operation name as a <CODE>String</CODE>. 
          <P></P></TR></TBODY></TABLE></A>
    <P></P></DD></DL><PRE><UL>
<LI>void unregisterOperationDescriptor(String operationName)
<P></P></LI></UL></PRE>
  <DL><A name=54714>
    <DT>
    <DD>unregisters an <CODE>OperationDescriptor</CODE> from the registry. </A>
    <P></P></DD></DL><PRE><UL>
<LI>void registerRIF(String operationName, String productName, 
       RenderedImageFactory RIF)
<P></P></LI></UL></PRE>
  <DL><A name=54736>
    <DT>
    <DD>registers a <CODE>RIF</CODE> with a particular product and operation.
    <P>
    <TABLE cellPadding=3 border=3>
      <CAPTION><FONT size=-1><B></B></FONT></CAPTION>
      <TBODY>
      <TR vAlign=top>
        <TD rowSpan=3><EM>Parameter</EM>:<EM></EM> 
          <P></P>
        <TD><CODE>operationName</CODE> 
          <P></P>
        <TD>The operation name as a <CODE>String</CODE>. 
          <P></P>