在php中imagecreate函数是一个图形处理函数,主要用于新建一个基于调色板的图像了,然后在这个基础上我们可以创建一些图形数字字符之类的,但这个函数需要GD库支持,如果没有开启GD库使用时会提示Call to undefined function imagecreate()错误.
例,我在测试一个简单生成图形时实例,新建一个新的 GD 图像流并输出图像,代码如下:
- <?php
- header("Content-type: image/png");
- $im = @imagecreate(100, 50)
- or die("Cannot Initialize new GD image stream");
- $background_color = imagecolorallocate($im, 255, 255, 255);
- $text_color = imagecolorallocate($im, 233, 14, 91);
- imagestring($im, 1, 5, 5, "A Simple Text String", $text_color);
- imagepng($im);
- imagedestroy($im);
-
- ?>
运行机制时提示:Fatal error: Call to undefined function imagecreate() .....
后面突然想起没打开gd库了,这一问题是,ＧＤ库没有正确安装或配置.
解决方案:在php.ini中找到 ;extension=php_gd2.dll 去掉前边的;,然后将php目录中的ext下的php_gd2.dll拷入c:/windows/system32和c:/windows目录下,重启IIS或者apache就OK了.
centos中gd库开启,具体操作只有2个命令如下,运行在线安装带GD库的PHP的命令,代码如下:
yum -y install php-gd
重新启动apachce服务以使安装后的GD库生效,代码如下:
/etc/rc.d/init.d/httpd restart(service httpd restart)
gd的安装路径:
/etc/php.d/gd.ini <---这个是让php支持gd的,这个是CentOS的特色之一,不用把全部东西都写在php.ini这个文件里,只是需要把*.ini文件写在/etc/php.d/文件夹就可以了,系统会自动把这个目录下的*.ini读入php.ini.
/usr/lib/php/modules/gd.so <----这个就是gd的文件.
关于需要使用GD库的图形处理函数还有如下:
- gd_?info
-
- getimagesize
-
- getimagesizefromstring
-
- image_?type_?to_?extension
-
- image_?type_?to_?mime_?type
-
- image2wbmp
-
- imageaffine
-
- imageaffinematrixconcat
-
- imageaffinematrixget
-
- imagealphablending
-
- imageantialias
-
- imagearc
-
- imagechar
-
- imagecharup
-
- imagecolorallocate
-
- imagecolorallocatealpha
-
- imagecolorat
-
- imagecolorclosest
-
- imagecolorclosestalpha
-
- imagecolorclosesthwb
-
- imagecolordeallocate
-
- imagecolorexact
-
- imagecolorexactalpha
-
- imagecolormatch
-
- imagecolorresolve
-
- imagecolorresolvealpha
-
- imagecolorset
-
- imagecolorsforindex
-
- imagecolorstotal
-
- imagecolortransparent
-
- imageconvolution
-
- imagecopy
-
- imagecopymerge
-
- imagecopymergegray
-
- imagecopyresampled
-
- imagecopyresized
-
- » imagecreate
-
- imagecreatefromgd2
-
- imagecreatefromgd2part
-
- imagecreatefromgd
-
- imagecreatefromgif
-
- imagecreatefromjpeg
-
- imagecreatefrompng
-
- imagecreatefromstring
-
- imagecreatefromwbmp
-
- imagecreatefromwebp
-
- imagecreatefromxbm
-
- imagecreatefromxpm
-
- imagecreatetruecolor
-
- imagecrop
-
- imagecropauto
-
- imagedashedline
-
- imagedestroy
-
- imageellipse
-
- imagefill
-
- imagefilledarc
-
- imagefilledellipse
-
- imagefilledpolygon
-
- imagefilledrectangle
-
- imagefilltoborder
-
- imagefilter
-
- imageflip
-
- imagefontheight
-
- imagefontwidth
-
- imageftbbox
-
- imagefttext
-
- imagegammacorrect
-
- imagegd2
-
- imagegd
-
- imagegif
-
- imagegrabscreen
-
- imagegrabwindow
-
- imageinterlace
-
- imageistruecolor
-
- imagejpeg
-
- imagelayereffect
-
- imageline
-
- imageloadfont
-
- imagepalettecopy
-
- imagepalettetotruecolor
-
- imagepng
-
- imagepolygon
-
- imagepsbbox
-
- imagepsencodefont
-
- imagepsextendfont
-
- imagepsfreefont
-
- imagepsloadfont
-
- imagepsslantfont
-
- imagepstext
-
- imagerectangle
-
- imagerotate
-
- imagesavealpha
-
- imagescale
-
- imagesetbrush
-
- imagesetinterpolation
-
- imagesetpixel
-
- imagesetstyle
-
- imagesetthickness
-
- imagesettile
-
- imagestring
-
- imagestringup
-
- imagesx
-
- imagesy
-
- imagetruecolortopalette
-
- imagettfbbox
-
- imagettftext
-
- imagetypes
-
- imagewbmp
-
- imagewebp
-
- imagexbm
-
- iptcembed
-
- iptcparse
-
- jpeg2wbmp
-
- png2wbmp
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