📄 3.3 图元输出与输出属性.htm
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<H2><FONT face=楷体_GB2312 size=5><SPAN lang=EN-US>3.3 </SPAN><SPAN
style="mso-ascii-font-family: Arial">图元输出与输出属性</SPAN></FONT></H2>
<H3 style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN
lang=EN-US><FONT face=楷体_GB2312 size=4>3.3.1 </FONT></SPAN><FONT face=楷体_GB2312
size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">二维图元输出</SPAN></FONT></H3>
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style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN lang=EN-US
style="mso-spacerun: yes"><FONT face=楷体_GB2312 size=4>
</FONT></SPAN><FONT face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">用户使用图形软件时，首先要告诉计算机的是画什么。图元是图形软件用于操作和组织画面的最基本的素材。一幅画面由图元组成。图元是一组最简单的、最通用的几何图形或字符。</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN lang=EN-US
style="mso-spacerun: yes"><FONT face=楷体_GB2312 size=4>
</FONT></SPAN><FONT face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">图形软件常用的图元有：</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN
lang=EN-US><SPAN style="mso-spacerun: yes"><FONT face=楷体_GB2312
size=4> </FONT></SPAN><FONT face=楷体_GB2312
size=4>line(</FONT></SPAN><FONT face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">直线段</SPAN><SPAN
lang=EN-US>)</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN
lang=EN-US><SPAN style="mso-spacerun: yes"><FONT face=楷体_GB2312
size=4> </FONT></SPAN><FONT face=楷体_GB2312
size=4>polyline(</FONT></SPAN><FONT face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">折线</SPAN><SPAN
lang=EN-US>)</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN
lang=EN-US><SPAN style="mso-spacerun: yes"><FONT face=楷体_GB2312
size=4> </FONT></SPAN><FONT face=楷体_GB2312
size=4>text(</FONT></SPAN><FONT face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">字符串</SPAN><SPAN
lang=EN-US>)</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN
lang=EN-US><SPAN style="mso-spacerun: yes"><FONT face=楷体_GB2312
size=4> </FONT></SPAN><FONT face=楷体_GB2312 size=4>fill
area(</FONT></SPAN><FONT face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">色块</SPAN><SPAN
lang=EN-US>)</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN
lang=EN-US><SPAN style="mso-spacerun: yes"><FONT face=楷体_GB2312
size=4> </FONT></SPAN><FONT face=楷体_GB2312
size=4>polymarker(</FONT></SPAN><FONT face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">符号的规迹</SPAN><SPAN
lang=EN-US>)</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN
lang=EN-US><SPAN style="mso-spacerun: yes"><FONT face=楷体_GB2312
size=4> </FONT></SPAN><FONT face=楷体_GB2312
size=4>move(</FONT></SPAN><FONT face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">现行位置的定位</SPAN><SPAN
lang=EN-US>)</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN
lang=EN-US><SPAN style="mso-spacerun: yes"><FONT face=楷体_GB2312
size=4> </FONT></SPAN><FONT face=楷体_GB2312 size=4>cell
array(</FONT></SPAN><FONT face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">象素矩阵</SPAN><SPAN
lang=EN-US>)</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN
lang=EN-US><SPAN style="mso-spacerun: yes"><FONT face=楷体_GB2312
size=4> </FONT></SPAN><FONT face=楷体_GB2312
size=4>circle(</FONT></SPAN><FONT face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">圆</SPAN><SPAN
lang=EN-US>)</SPAN></FONT></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman"><FONT
face=楷体_GB2312
size=4>每一种图元都由一系列系数描述其性质。在图形软件包中这些参数由两类命令定义：一类是输出图元命令，它描述了图元的种类及其最重要、也是变化最频繁的参数，如直线之端点坐标。另一类是图元性质定义的命令，它描述了图元的其余性质，如直线之宽度、线型等等。从实现的角度来看，用户定义的二维图元的窗口区到视图区的输出过程如下所示：</FONT></SPAN></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><FONT
face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">从应用程序得到的用户（</SPAN><SPAN
lang=EN-US>WC</SPAN><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">）</SPAN><SPAN
lang=EN-US
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman; mso-char-type: symbol; mso-symbol-font-family: Symbol; mso-bidi-font-size: 10.0pt">®</SPAN><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">对窗口区进行裁剪（</SPAN><SPAN
lang=EN-US>WC</SPAN><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">）</SPAN><SPAN
lang=EN-US
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman; mso-char-type: symbol; mso-symbol-font-family: Symbol; mso-bidi-font-size: 10.0pt">®</SPAN><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">窗口区到视图区的规格化变换（</SPAN><SPAN
lang=EN-US>NDC</SPAN><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">）</SPAN><SPAN
lang=EN-US
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman; mso-char-type: symbol; mso-symbol-font-family: Symbol; mso-bidi-font-size: 10.0pt">®</SPAN><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">视图区的规格化坐标系到设备坐标系的变换（</SPAN><SPAN
lang=EN-US>DC</SPAN><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">）</SPAN><SPAN
lang=EN-US
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman; mso-char-type: symbol; mso-symbol-font-family: Symbol; mso-bidi-font-size: 10.0pt">®</SPAN><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">调用基本图元生成算法</SPAN><SPAN
lang=EN-US>(</SPAN><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">参见第二章</SPAN><SPAN
lang=EN-US>)</SPAN><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">在图形设备上输出图形</SPAN></FONT></P>
<P class=MsoNormal
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lang=EN-US><FONT face=楷体_GB2312 size=4> <O:P> </O:P></FONT></SPAN></P>
<P class=MsoNormal
style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN
lang=EN-US><FONT face=楷体_GB2312 size=4>3.3.1.1 </FONT></SPAN><FONT
face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">输出图元的命令</SPAN><SPAN
lang=EN-US><O:P> </O:P></SPAN></FONT></P>
<P class=MsoNormal
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style="mso-spacerun: yes"><FONT face=楷体_GB2312 size=4>
</FONT></SPAN><FONT face=楷体_GB2312 size=4><SPAN
style="mso-ascii-font-family: Times New Roman; mso-hansi-font-family: Times New Roman">一、</SPAN><SPAN
lang=EN-US>move(x,y)</SPAN></FONT></P>
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style="MARGIN: 1px 0px; TEXT-INDENT: 0px; LINE-HEIGHT: 200%"><SPAN lang=EN-US
style="mso-spacerun: yes"><FONT face=楷体_GB2312 size=4>
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