以下常量由本扩展模块定义，因此只有在本扩展模块被编译到 PHP 中，或者在运行时被动态加载后才有效。
The following two tables lists all constants defined by the ps extension.
| Name | Meaning |
|---|---|
| ps_LINECAP_BUTT | |
| ps_LINECAP_ROUND | |
| ps_LINECAP_SQUARED |
| Name | Meaning |
|---|---|
| ps_LINEJOIN_MITER | |
| ps_LINEJOIN_ROUND | |
| ps_LINEJOIN_BEVEL |