1abe3a6eaShanjiezhou# 屏幕管理器（SCM） 2abe3a6eaShanjiezhou 3abe3a6eaShanjiezhou:::{note} 4abe3a6eaShanjiezhou作者: 周瀚杰 <2625553453@qq.com> 5abe3a6eaShanjiezhou::: 6abe3a6eaShanjiezhou  屏幕管理器用来管理控制所有ui框架，所有框架都必须先在屏幕管理器中注册才可使用，然后scm控制当前是哪个ui框架在使用 7abe3a6eaShanjiezhou 8abe3a6eaShanjiezhou## traits 9abe3a6eaShanjiezhou 10abe3a6eaShanjiezhou### ScmUiFramework 11abe3a6eaShanjiezhou  每个要注册到scm中的ui框架都必须实现这个trait中的方法，具体定义如下： 12abe3a6eaShanjiezhou```rust 13abe3a6eaShanjiezhoupub trait ScmUiFramework: Sync + Send + Debug { 14abe3a6eaShanjiezhou // 安装ui框架的回调函数 15abe3a6eaShanjiezhou fn install(&self) -> Result<i32, SystemError> { 16*1074eb34SSamuel Dai return Err(SystemError::ENOSYS); 17abe3a6eaShanjiezhou } 18abe3a6eaShanjiezhou // 卸载ui框架的回调函数 19abe3a6eaShanjiezhou fn uninstall(&self) -> Result<i32, SystemError> { 20*1074eb34SSamuel Dai return Err(SystemError::ENOSYS); 21abe3a6eaShanjiezhou } 22abe3a6eaShanjiezhou // 启用ui框架的回调函数 23abe3a6eaShanjiezhou fn enable(&self) -> Result<i32, SystemError> { 24*1074eb34SSamuel Dai return Err(SystemError::ENOSYS); 25abe3a6eaShanjiezhou } 26abe3a6eaShanjiezhou // 禁用ui框架的回调函数 27abe3a6eaShanjiezhou fn disable(&self) -> Result<i32, SystemError> { 28*1074eb34SSamuel Dai return Err(SystemError::ENOSYS); 29abe3a6eaShanjiezhou } 30abe3a6eaShanjiezhou // 改变ui框架的帧缓冲区的回调函数 31abe3a6eaShanjiezhou fn change(&self, _buf: ScmBufferInfo) -> Result<i32, SystemError> { 32*1074eb34SSamuel Dai return Err(SystemError::ENOSYS); 33abe3a6eaShanjiezhou } 34abe3a6eaShanjiezhou /// @brief 获取ScmUiFramework的元数据 35abe3a6eaShanjiezhou /// @return 成功：Ok(ScmUiFramework的元数据) 36abe3a6eaShanjiezhou /// 失败：Err(错误码) 37abe3a6eaShanjiezhou fn metadata(&self) -> Result<ScmUiFrameworkMetadata, SystemError> { 38abe3a6eaShanjiezhou // 若文件系统没有实现此方法，则返回“不支持” 39*1074eb34SSamuel Dai return Err(SystemError::ENOSYS); 40abe3a6eaShanjiezhou } 41abe3a6eaShanjiezhou} 42abe3a6eaShanjiezhou``` 43abe3a6eaShanjiezhou## 主要API 44abe3a6eaShanjiezhou### scm_init() -初始化屏幕管理模块 45abe3a6eaShanjiezhou#### 原型 46abe3a6eaShanjiezhou```rust 47abe3a6eaShanjiezhoupub extern "C" fn scm_init() 48abe3a6eaShanjiezhou``` 49abe3a6eaShanjiezhou#### 说明 50abe3a6eaShanjiezhou  scm_init()主要是初始化一些scm中使用的全局变量，例如是否使用双缓冲区标志位，textui未初始化时使用的一些全局变量 51abe3a6eaShanjiezhou 52abe3a6eaShanjiezhou### scm_reinit() -当内存管理单元被初始化之后，重新初始化屏幕管理模块 53abe3a6eaShanjiezhou#### 原型 54abe3a6eaShanjiezhou```rust 55abe3a6eaShanjiezhoupub extern "C" fn scm_reinit() -> i32 56abe3a6eaShanjiezhou``` 57abe3a6eaShanjiezhou#### 说明 58abe3a6eaShanjiezhou  scm_reinit()用于当内存管理单元被初始化之后，重新处理帧缓冲区问题 59abe3a6eaShanjiezhou 60abe3a6eaShanjiezhou### scm_enable_double_buffer() -允许双缓冲区 61abe3a6eaShanjiezhou#### 原型 62abe3a6eaShanjiezhou```rust 63abe3a6eaShanjiezhoupub extern "C" fn scm_enable_double_buffer() -> i32 64abe3a6eaShanjiezhou``` 65abe3a6eaShanjiezhou#### 说明 66abe3a6eaShanjiezhou  scm_enable_double_buffer()用于启动双缓冲来往窗口输出打印信息。启用后，往窗口输出的信息会暂时放在一个缓冲区中，然后每次按一定时间将该缓冲区的信息输出到窗口帧缓冲区中，渲染显示到窗口上。 67abe3a6eaShanjiezhou 68abe3a6eaShanjiezhou### scm_framework_enable（） -启用某个ui框架，将它的帧缓冲区渲染到屏幕上 69abe3a6eaShanjiezhou#### 原型 70abe3a6eaShanjiezhou```rust 71abe3a6eaShanjiezhoupub fn scm_framework_enable(framework: Arc<dyn ScmUiFramework>) -> Result<i32, SystemError> 72abe3a6eaShanjiezhou``` 73abe3a6eaShanjiezhou#### 说明 74abe3a6eaShanjiezhou  scm_framework_enable用于启用某个ui框架，将它的帧缓冲区渲染到屏幕上 75abe3a6eaShanjiezhou 76abe3a6eaShanjiezhou 77abe3a6eaShanjiezhou### scm_register（） -向屏幕管理器注册UI框架 78abe3a6eaShanjiezhou#### 原型 79abe3a6eaShanjiezhou```rust 80abe3a6eaShanjiezhoupub fn scm_register(framework: Arc<dyn ScmUiFramework>) -> Result<i32, SystemError> 81abe3a6eaShanjiezhou``` 82abe3a6eaShanjiezhou#### 说明 83abe3a6eaShanjiezhou  scm_register用于将ui框架注册到scm中，主要是调用ui框架的回调函数以安装ui框架，并将其激活 84