📄 extending the api.htm
字号:
<TABLE cellPadding=3 border=3>
<CAPTION><FONT size=-1><B></B></FONT></CAPTION>
<TBODY>
<TR vAlign=top>
<TD rowSpan=2><EM>Parameters</EM>:<EM></EM>
<P></P>
<TD><CODE>ras</CODE>
<P></P>
<TD>A read-only <CODE>Raster</CODE> source.
<P></P>
<TR vAlign=top>
<TD><CODE>bounds</CODE>
<P></P>
<TD>The bounding <CODE>Rectangle</CODE> for the iterator, or null.
<P></P></TR></TBODY></TABLE></A>
<P></P></DD></DL><A name=57770>
<H3>14.4.4 <IMG src="Extending the API.files/space.gif">Example
RectIter</H3></A><A
href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Extension.doc.html#57929">Listing
14-3</A> shows an example of the construction of a new <CODE>RectIter</CODE>.
<P><CAPTION><FONT size=-1><B><A name=57929>
<CENTER><FONT size=-1><B><I>Listing 14-3 </I><IMG
src="Extending the API.files/sm-blank.gif" border=0> Example
RectIter</B></FONT></CENTER></A>
<P></B></FONT></CAPTION>
<HR>
<TR valign="top"><TD rowspan="9" colspan="1"><PRE> import java.awt.Rectangle;
import java.awt.image.ColorModel;
import java.awt.image.DataBuffer;
import java.awt.image.PixelInterleavedSampleModel;
import java.awt.image.SampleModel;
import java.util.Random;
import javax.media.jai.*;
import javax.media.jai.iterator.*;
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TD rowspan="2" colspan="1"><PRE> class RectIterTest {
</PRE><TR valign="top"><TR valign="top"><TD rowspan="5" colspan="1"><PRE> int width = 10;
int height = 10;
int tileWidth = 4;
int tileHeight = 4;
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TD rowspan="4" colspan="1"><PRE> public static void main(String[] args) {
new RectIterTest();
}
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TD
rowspan="2" colspan="1"><PRE> public RectIterTest() {
</PRE><TR valign="top"><TR valign="top"><TD rowspan="3" colspan="1"><PRE> Random rand = new Random(1L);
Rectangle rect = new Rectangle();
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TD rowspan="8"
colspan="1"><PRE> int[] bandOffsets = { 2, 1, 0 };
SampleModel sampleModel =
new PixelInterleavedSampleModel(DataBuffer.TYPE_BYTE,
tileWidth, tileHeight,
3, 3*tileWidth,
bandOffsets);
ColorModel colorModel = null;
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TD
rowspan="4" colspan="1"><PRE> TiledImage im = new TiledImage(0, 0, width, height, 0, 0,
sampleModel,
colorModel);
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TD
rowspan="3" colspan="1"><PRE> int[][][] check = new int[width][height][3];
int x, y, b;
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TD rowspan="4"
colspan="1"><PRE> for (int i = 0; i < 10; i++) {
rect.x = rand.nextInt(width);
rect.width = rand.nextInt(width - rect.x) + 1;
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TD
rowspan="3" colspan="1"><PRE> rect.y = rand.nextInt(height);
rect.height = rand.nextInt(height - rect.y) + 1;
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TD rowspan="2"
colspan="1"><PRE> System.out.println("Filling rect " + rect + " with " + i);
</PRE><TR valign="top"><TR valign="top"><TD rowspan="2" colspan="1"><PRE> WritableRectIter witer = RectIterFactory.createWritable(im,
rect);
</PRE><TR valign="top"><TR valign="top"><TD rowspan="12" colspan="1"><PRE> b = 0;
witer.startBands();
while (!witer.finishedBands()) {
y = rect.y;
witer.startLines();
while (!witer.finishedLines()) {
x = rect.x;
witer.startPixels();
while (!witer.finishedPixels()) {
witer.setSample(i);
check[x][y][b] = i;
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TD
rowspan="4" colspan="1"><PRE> ++x;
witer.nextPixel();
}
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TD
rowspan="4" colspan="1"><PRE> ++y;
witer.nextLine();
}
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TD
rowspan="5" colspan="1"><PRE> ++b;
witer.nextBand();
}
}
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TD rowspan="6" colspan="1"><PRE> rect.x = 0;
rect.y = 0;
rect.width = width;
rect.height = height;
RectIter iter = RectIterFactory.createWritable(im, rect);
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TR valign="top"><TD rowspan="5" colspan="1"><PRE> b = 0;
iter.startBands();
while (!iter.finishedBands()) {
System.out.println();
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TD rowspan="4" colspan="1"><PRE> y = 0;
iter.startLines();
while (!iter.finishedLines()) {
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TD
rowspan="6" colspan="1"><PRE> x = 0;
iter.startPixels();
while (!iter.finishedPixels()) {
int val = iter.getSample();
System.out.print(val);
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TR valign="top"><TD rowspan="6" colspan="1"><PRE> if (val != check[x][y][b]) {
System.out.print("(" + check[x][y][b] + ") ");
} else {
System.out.print(" ");
}
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TR valign="top"><TD rowspan="4" colspan="1"><PRE> ++x;
iter.nextPixel();
}
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TD
rowspan="5" colspan="1"><PRE> ++y;
iter.nextLine();
System.out.println();
}
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TR
valign="top"><TD rowspan="5" colspan="1"><PRE> ++b;
iter.nextBand();
}
}
}
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top">
<HR>
<P><A name=56033>
<H2>14.5 <IMG src="Extending the API.files/space.gif">Writing New Image
Decoders and Encoders</H2></A>The <CODE>sample</CODE> directory contains an
example of how to create a new image codec. The example is of a PNM codec, but
can be used as a basis for creating any codec. The PNM codec consists of three
files:
<P>
<TABLE cellPadding=3 border=3>
<CAPTION><FONT size=-1><B></B></FONT></CAPTION>
<TBODY>
<TR vAlign=top>
<TH><A name=58309>File Name </A>
<TH><A name=58311>Description </A>
<TR vAlign=top>
<TD><A name=58313>SamplePNMCodec.java</A><BR>
<TD><A name=58315>Defines a subclass of ImageCodec for handling the PNM
family of image files.</A><BR>
<TR vAlign=top>
<TD><A name=58317>SamplePNMImageDecoder.java</A><BR>
<TD><A name=58319>Defines an ImageDecoder for the PNM family of image
files. Necessary for reading PNM files.</A><BR>
<TR vAlign=top>
<TD><A name=58321>SamplePNMImageEncoder.java</A><BR>
<TD><A name=58323>Defines an ImageEncoder for the PNM family of image
files. Necessary for writing PNM files.</A><BR></TR></TBODY></TABLE>
<P><A name=51534>
<H3>14.5.1 <IMG src="Extending the API.files/space.gif">Image Codecs</H3></A>
<HR noShade>
<B>Note:</B> The codec classes are provided for the developer as a convenience
for file IO. These classes are not part of the official Java Advanced Imaging
API and are subject to change as a result of the near future File IO extension
API. Until the File IO extension API is defined, these classes and functions
will be supported for JAI use.
<HR noShade>
The <CODE>ImageCodec</CODE> class allows the creation of image decoders and
encoders. Instances of <CODE>ImageCodec</CODE> may be registered by name. The
<CODE>registerCodec</CODE> method associates an <CODE>ImageCodec</CODE> with
the given name. Any codec previously associated with the name is discarded.
Once a codec has been registered, the name associated with it may be used as
the <CODE>name</CODE> parameter in the <CODE>createImageEncoder</CODE> and
<CODE>createImageDecoder</CODE> methods.
<P>The <CODE>ImageCodec</CODE> class maintains a registry of
<CODE>FormatRecognizer</CODE> objects that examine an <CODE>InputStream</CODE>
and determine whether it adheres to the format handled by a particular
<CODE>ImageCodec</CODE>. A <CODE>FormatRecognizer</CODE> is added to the
registry with the <CODE>registerFormatRecognizer</CODE> method. The
unregisterFormatRecognizer method removes a previously registered
<CODE>FormatRecognizer</CODE> from the registry.
<P>The <CODE>getCodec</CODE> method returns the <CODE>ImageCodec</CODE>
associated with a given name. If no codec is registered with the given name,
<CODE>null</CODE> is returned.<CODE></CODE>
<P>
<TABLE border=0>
<TBODY>
<TR>
<TD><IMG src="Extending the API.files/cistine.gif"></TD>
<TD>
<HR>
<B>API:</B> <CODE>com.sun.media.jai.codec.ImageCodec </CODE>
<HR>
</TD></TR></TBODY></TABLE><PRE><UL>
<LI>static ImageEncoder createImageEncoder(String name,
OutputStream dst, ImageEncodeParam param)
<P></P></LI></UL></PRE>
<DL><A name=54386>
<DT>
<DD>returns an <CODE>ImageEncoder</CODE> object suitable for encoding to the
supplied <CODE>OutputStream</CODE>, using the supplied
<CODE>ImageEncodeParam</CODE> object.
<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>name</CODE>
<P></P>
<TD>The name associated with the codec.
<P></P>
<TR vAlign=top>
<TD><CODE>dst</CODE>
<P></P>
<TD>An <CODE>OutputStream</CODE> to write to.
<P></P>
<TR vAlign=top>
<TD><CODE>param</CODE>
<P></P>
<TD>An instance of ImageEncodeParam suitable for use with the named
codec, or null.
<P></P></TR></TBODY></TABLE></A>
<P></P></DD></DL><PRE><UL>
<LI>static ImageEncoder createImageEncoder(String name,
OutputStream dst)
<P></P></LI></UL></PRE>
<DL><A name=54450>
<DT>
<DD>returns an <CODE>ImageEncoder</CODE> object suitable for encoding to the
supplied <CODE>OutputStream</CODE> object. A null
<CODE>ImageEncodeParam</CODE> is used. </A>
<P></P></DD></DL><PRE><UL>
<LI>static ImageDecoder createImageDecoder(String name,
InputStream src, ImageDecodeParam param)
<P></P></LI></UL></PRE>
<DL><A name=54475>
<DT>
<DD>returns an <CODE>ImageDecoder</CODE> object suitable for decoding from
the supplied <CODE>InputStream</CODE>, using the supplied
<CODE>ImageDecodeParam</CODE> object.
<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>name</CODE>
<P></P>
<TD>The name associated with the codec.
<P></P>
<TR vAlign=top>
<TD><CODE>src</CODE>
<P></P>
<TD>An <CODE>InputStream</CODE> to read from.
<P></P>
<TR vAlig⌨️ 快捷键说明
复制代码
Ctrl + C
搜索代码
Ctrl + F
全屏模式
F11
切换主题
Ctrl + Shift + D
显示快捷键
?
增大字号
Ctrl + =
减小字号
Ctrl + -