graphics rendering.htm

是一部关于java高级图像处理的的一本入门书

      <TD><A name=51872>Ends unclosed subpaths with a square projection that 
        extends beyond the end of the segment to a distance equal to half the 
        line width.</A><BR></TR></TBODY></TABLE>
  <P>To set the endcap style, create a <CODE>BasicStroke</CODE> object with the 
  desired attribute. The following example sets the stroke width to 12 points 
  and endcap style is set to <CODE>CAP_ROUND</CODE>. 
  <P><PRE><HR>
     wideStroke = new BasicStroke(12.0, BasicStroke.CAP_ROUND);
</PRE><PRE>     g2.setStroke(roundStroke);

<HR></PRE><A name=51899>
  <H4>10.2.2.3 <IMG src="Graphics Rendering.files/space.gif">Join 
  Style</H4></A><A 
  href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Graphics.doc.html#51903">Table 
  10-2</A> lists the join style attributes. These attributes affect the 
  appearance of line junctions.
  <P>
  <TABLE cellPadding=3 border=3>
    <CAPTION><FONT size=-1><B><A name=51903><I>Table 10-2 </I><IMG 
    src="Graphics Rendering.files/sm-blank.gif" border=0> Join Styles 
    </A></B></FONT></CAPTION>
    <TBODY>
    <TR vAlign=top>
      <TH><A name=51909>Appearance </A>
      <TH><A name=51911>Attribute </A>
      <TH><A name=51913>Description </A>
    <TR vAlign=top>
      <TD><A name=51915>
        <HR>

        <CENTER><IMG 
        src="Graphics Rendering.files/Graphics.doc.anc4.gif"></CENTER>
        <HR>
        </A><BR>
      <TD><A name=51917>JOIN_BEVEL</A><BR>
      <TD><A name=51944>Joins path segments by connecting the outer corners of 
        their wide outlines with a straight segment.</A><BR>
    <TR vAlign=top>
      <TD><A name=51921>
        <HR>

        <CENTER><IMG 
        src="Graphics Rendering.files/Graphics.doc.anc5.gif"></CENTER>
        <HR>
        </A><BR>
      <TD><A name=51923>JOIN_ROUND</A><BR>
      <TD><A name=51978>Joins path segments by rounding off the corner at a 
        radius of half the line width.</A><BR>
    <TR vAlign=top>
      <TD><A name=51927>
        <HR>

        <CENTER><IMG 
        src="Graphics Rendering.files/Graphics.doc.anc6.gif"></CENTER>
        <HR>
        </A><BR>
      <TD><A name=51929>JOIN_MITER</A><BR>
      <TD><A name=51985>Joins path segments by extending their outside edges 
        until they meet.</A><BR></TR></TBODY></TABLE>
  <P>To set the join style, create a <CODE>BasicStroke</CODE> object with the 
  desired attribute. The following example sets the stroke width to 12 points, 
  an endcap style of <CODE>CAP_ROUND</CODE>, and a join style of 
  <CODE>JOIN_ROUND</CODE>. 
  <P><PRE><HR>
     wideStroke = new BasicStroke(12.0, BasicStroke.CAP_ROUND,
</PRE><PRE>                                  BasicStroke.JOIN_ROUND);
</PRE><PRE>     g2.setStroke(roundStroke);

<HR></PRE><A name=51991>
  <H4>10.2.2.4 <IMG src="Graphics Rendering.files/space.gif">Stroke 
  Style</H4></A>The stroke style is defined by two parameters: 
  <P>
  <UL>
    <LI><CODE>dash</CODE> - an array that represents the dashing pattern. 
    Alternating elements in the array represent the dash size and the size of 
    the space between dashes. Element 0 represents the first dash, element 1 
    represents the first space.
    <P></P></LI></UL>
  <UL>
    <LI><CODE>dash_phase</CODE> - an offset that defines where the dashing 
    pattern starts.
    <P></P></LI></UL><A 
  href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Graphics.doc.html#52134">Listing 
  10-1</A> shows a code sample in which two different dashing patterns are 
  created. In the first pattern, the size of the dashes and the space between 
  them is constant. The second pattern uses a six-element array to define the 
  dashing pattern. The two dash patterns are shown in <A 
  href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Graphics.doc.html#52035">Figure 
  10-2</A>.
  <P><CAPTION><FONT size=-1><B><A name=52134>
  <CENTER><FONT size=-1><B><I>Listing 10-1 </I><IMG 
  src="Graphics Rendering.files/sm-blank.gif" border=0> Example Stroke 
  Styles</B></FONT></CENTER></A>
  <P></B></FONT></CAPTION>
  <HR>
  <TR valign="top"><TD rowspan="3" colspan="1"><PRE>     // Define the first dashed line.
     float dash1[] = {10.0f};
     BasicStroke bs = new BasicStroke(5.0f, BasicStroke.CAP_BUTT,
                          BasicStroke.JOIN_MITER, 10.0f, dash1, 0.0f);
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TD rowspan="3" 
  colspan="1"><PRE>     g2.setStroke(bs);
     Line2D line = new Line2D.Float(20.0f, 10.0f, 100.0f, 10.0f);
     g2.draw(line);
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TD><PRE>     // Define the second dashed line.
     float[] dash2 = {6.0f, 4.0f, 2.0f, 4.0f, 2.0f, 4.0f};
     bs = new BasicStroke(5.0f, BasicStroke.CAP_BUTT,
                          BasicStroke.JOIN_MITER, 10.0f, dash2, 0.0f);
     g2.setStroke(bs);
     g2.draw(line);
</PRE>
  <HR>

  <P><A name=52034>
  <HR>

  <CENTER><IMG src="Graphics Rendering.files/Graphics.doc.anc7.gif"></CENTER>
  <HR>
  </A><A name=52035>
  <CENTER><FONT size=-1><B><I>Figure 10-2 </I><IMG 
  src="Graphics Rendering.files/sm-blank.gif" border=0> Example Stroke 
  Styles</B></FONT></CENTER></A>
  <P><A name=52119>
  <H4>10.2.2.5 <IMG src="Graphics Rendering.files/space.gif">Fill 
  Styles</H4></A>The <CODE>Paint</CODE> attribute in the <CODE>Graphics2D</CODE> 
  context defines the fill color or pattern used when text and 
  <CODE>Shape</CODE>s are rendered. 
  <P><A name=52121>
  <H5>Filling a Shape with a Gradient</H5></A>The <CODE>GradientPaint</CODE> 
  class allows a shape to be filled with a gradient of one color to another. 
  When creating a <CODE>GradientPaint</CODE> object, you specify a beginning 
  position and color, and an ending position and color. The fill color changes 
  proportionally from one color to the other along the line connecting the two 
  positions, as shown in <A 
  href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Graphics.doc.html#52622">Figure 
  10-3</A>. 
  <P>In all three stars, the gradient line extends from point P1 to point P2. In 
  the middle star, all of the points along the gradient line extending to the 
  left of P1 take the beginning color and the points to the right of P2 take the 
  ending color. 
  <P><A name=52621>
  <HR>

  <CENTER><IMG src="Graphics Rendering.files/Graphics.doc.anc8.gif"></CENTER>
  <HR>
  </A><A name=52622>
  <CENTER><FONT size=-1><B><I>Figure 10-3 </I><IMG 
  src="Graphics Rendering.files/sm-blank.gif" border=0> Filling a Shape with a 
  Gradient</B></FONT></CENTER></A>
  <P>To fill a shape with a gradient of one color to another: 
  <P>
  <UL>1. Create a <CODE>GradientPaint</CODE> object
    <P>2. Call <CODE>Graphics2D.setPaint</CODE>
    <P>3. Create the <CODE>Shape</CODE> object
    <P>4. Call <CODE>Graphics2D.fill(shape)</CODE>
    <P></P></UL><A 
  href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Graphics.doc.html#52145">Listing 
  10-2</A> shows sample code in which a rectangle is filled with a blue-green 
  gradient.
  <P><CAPTION><FONT size=-1><B><A name=52145>
  <CENTER><FONT size=-1><B><I>Listing 10-2 </I><IMG 
  src="Graphics Rendering.files/sm-blank.gif" border=0> Example Filling a 
  Rectangle with a Gradient</B></FONT></CENTER></A>
  <P></B></FONT></CAPTION>
  <HR>
  <TR valign="top"><TD rowspan="4" colspan="1"><PRE>     GradientPaint gp = new GradientPaint(50.0f, 50.0f, Color.blue,
                                          50.0f, 250.0f, Color.green);
     g2.setPaint(gp);
     g2.fillRect(50, 50, 200, 200);
</PRE><TR valign="top"><TR valign="top"><TR valign="top">
  <HR>

  <P><A name=52161>
  <H5>Filling a Shape with a Texture</H5></A>The <CODE>TexturePaint</CODE> class 
  allows you to fill a shape with a repeating pattern. When you create a 
  <CODE>TexturePaint</CODE>, you specify a <CODE>BufferedImage</CODE> to use as 
  the pattern. You also pass the constructor a rectangle to define the 
  repetition frequency of the pattern. 
  <P>To fill a shape with a texture: 
  <P>
  <UL>1. Create a <CODE>TexturePaint</CODE> object
    <P>2. Call <CODE>Graphics2D.setPaint</CODE>
    <P>3. Create the <CODE>Shape</CODE>
    <P>4. Call <CODE>Graphics2D.fill(shape)</CODE>
    <P></P></UL><A 
  href="http://java.sun.com/products/java-media/jai/forDevelopers/jai1_0_1guide-unc/Graphics.doc.html#52179">Listing 
  10-3</A> shows sample code in which a shape is filled with texture.
  <P><CAPTION><FONT size=-1><B><A name=52179>
  <CENTER><FONT size=-1><B><I>Listing 10-3 </I><IMG 
  src="Graphics Rendering.files/sm-blank.gif" border=0> Example Filling a Shape 
  with Texture</B></FONT></CENTER></A>
  <P></B></FONT></CAPTION>
  <HR>
  <TR valign="top"><TD rowspan="4" colspan="1"><PRE>     // Create a buffered image texture patch of size 5 X 5.
     BufferedImage bi = new BufferedImage(5, 5,
                            BufferedImage.TYPE_INT_RGB);
     Graphics2D big bi.createGraphics();
</PRE><TR valign="top"><TR valign="top"><TR valign="top"><TR valign="top"><TD><PRE>     // Render into the BufferedImage graphics to create the texture.
     big.setColor(Color.green);
     big.fillRect(0, 0, 5, 5);
     big.setColor(Color.lightGray);
     big.fillOval(0, 0, 5, 5);
</PRE><TR valign="top"><TD><PRE>     // Create a texture paint from the buffered image.
     Rectangle r = new Rectangle(0, 0, 5, 5);
     TexturePaint tp = new
         TexturePaint(bi, r, TexturePaint.NEAREST_NEIGHBOR);
</PRE><TR valign="top"><TD><PRE>     // Add the texture paint to the graphics context.
     g2.setPaint(tp);
</PRE><TR valign="top"><TD><PRE>     // Create and render a rectangle filled with the texture.
     g2.fillRect(0, 0, 200, 200);