安装 ImageMagick 遇到的常见问题

问题 attempt to perform an operation not allowed by the security policy

转换出现 convert: attempt to perform an operation not allowed by the security policy PDF @ error/constitute.c/IsCoderAuthorized/421.\nconvert: no images defined。

出现这个问题是因为 ImageMagick 默认禁用了对 PDF 文件的处理。解决方法是，修改文件 /etc/ImageMagick-6/policy.xml，只需要注释掉以下内容：

<!-- disable ghostscript format types -->
<policy domain="coder" rights="none" pattern="PS" />
<policy domain="coder" rights="none" pattern="PS2" />
<policy domain="coder" rights="none" pattern="PS3" />
<policy domain="coder" rights="none" pattern="EPS" />
<policy domain="coder" rights="none" pattern="PDF" />
<policy domain="coder" rights="none" pattern="XPS" />