<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <HTML ><HEAD ><TITLE >imagecolorat</TITLE ><META NAME="GENERATOR" CONTENT="Modular DocBook HTML Stylesheet Version 1.79"><LINK REL="HOME" TITLE="PHP 手册" HREF="index.html"><LINK REL="UP" TITLE="Image 图像函数" HREF="ref.image.html"><LINK REL="PREVIOUS" TITLE="imagecolorallocatealpha" HREF="function.imagecolorallocatealpha.html"><LINK REL="NEXT" TITLE="imagecolorclosest" HREF="function.imagecolorclosest.html"><META HTTP-EQUIV="Content-type" CONTENT="text/html; charset=UTF-8"></HEAD ><BODY CLASS="refentry" BGCOLOR="#FFFFFF" TEXT="#000000" LINK="#0000FF" VLINK="#840084" ALINK="#0000FF" ><DIV CLASS="NAVHEADER" ><TABLE SUMMARY="Header navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TH COLSPAN="3" ALIGN="center" >PHP 手册</TH ></TR ><TR ><TD WIDTH="10%" ALIGN="left" VALIGN="bottom" ><A HREF="function.imagecolorallocatealpha.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="80%" ALIGN="center" VALIGN="bottom" ></TD ><TD WIDTH="10%" ALIGN="right" VALIGN="bottom" ><A HREF="function.imagecolorclosest.html" ACCESSKEY="N" >下一页</A ></TD ></TR ></TABLE ><HR ALIGN="LEFT" WIDTH="100%"></DIV ><H1 ><A NAME="function.imagecolorat" ></A >imagecolorat</H1 ><DIV CLASS="refnamediv" ><A NAME="AEN87168" ></A ><P > (PHP 3, PHP 4, PHP 5)</P >imagecolorat -- 取得某像素的颜色索引值</DIV ><DIV CLASS="refsect1" ><A NAME="AEN87171" ></A ><H2 >说明</H2 >int <B CLASS="methodname" >imagecolorat</B > ( resource image, int x, int y )<BR ></BR ><P > 返回 <CODE CLASS="parameter" >image</CODE > 所指定的图形中指定位置像素的颜色索引值。 </P ><P > 如果 PHP 编译时加上了 GD 库 2.0 或更高的版本并且图像是真彩色图像,则本函数以整数返回该点的 RGB 值。用移位加掩码来取得红,绿,蓝各自成分的值: <TABLE WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" CLASS="EXAMPLE" ><TR ><TD ><DIV CLASS="example" ><A NAME="AEN87188" ></A ><P ><B >例 1. 取得各自的 RGB 值</B ></P ><TABLE BORDER="0" BGCOLOR="#E0E0E0" CELLPADDING="5" ><TR ><TD ><code><font color="#000000"> <font color="#0000BB"><?php<br />$im </font><font color="#007700">= </font><font color="#0000BB">ImageCreateFromPng</font><font color="#007700">(</font><font color="#DD0000">"rockym.png"</font><font color="#007700">);<br /></font><font color="#0000BB">$rgb </font><font color="#007700">= </font><font color="#0000BB">ImageColorAt</font><font color="#007700">(</font><font color="#0000BB">$im</font><font color="#007700">, </font><font color="#0000BB">100</font><font color="#007700">, </font><font color="#0000BB">100</font><font color="#007700">);<br /></font><font color="#0000BB">$r </font><font color="#007700">= (</font><font color="#0000BB">$rgb </font><font color="#007700">>> </font><font color="#0000BB">16</font><font color="#007700">) & </font><font color="#0000BB">0xFF</font><font color="#007700">;<br /></font><font color="#0000BB">$g </font><font color="#007700">= (</font><font color="#0000BB">$rgb </font><font color="#007700">>> </font><font color="#0000BB">8</font><font color="#007700">) & </font><font color="#0000BB">0xFF</font><font color="#007700">;<br /></font><font color="#0000BB">$b </font><font color="#007700">= </font><font color="#0000BB">$rgb </font><font color="#007700">& </font><font color="#0000BB">0xFF</font><font color="#007700">;<br /></font><font color="#0000BB">?></font> </font> </code></TD ></TR ></TABLE ></DIV ></TD ></TR ></TABLE > </P ><P > 参见 <A HREF="function.imagecolorset.html" ><B CLASS="function" >imagecolorset()</B ></A > 和 <A HREF="function.imagecolorsforindex.html" ><B CLASS="function" >imagecolorsforindex()</B ></A >。 </P ></DIV ><DIV CLASS="NAVFOOTER" ><HR ALIGN="LEFT" WIDTH="100%"><TABLE SUMMARY="Footer navigation table" WIDTH="100%" BORDER="0" CELLPADDING="0" CELLSPACING="0" ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" ><A HREF="function.imagecolorallocatealpha.html" ACCESSKEY="P" >上一页</A ></TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="index.html" ACCESSKEY="H" >起始页</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" ><A HREF="function.imagecolorclosest.html" ACCESSKEY="N" >下一页</A ></TD ></TR ><TR ><TD WIDTH="33%" ALIGN="left" VALIGN="top" >imagecolorallocatealpha</TD ><TD WIDTH="34%" ALIGN="center" VALIGN="top" ><A HREF="ref.image.html" ACCESSKEY="U" >上一级</A ></TD ><TD WIDTH="33%" ALIGN="right" VALIGN="top" >imagecolorclosest</TD ></TR ></TABLE ></DIV ></BODY ></HTML >