lite源码阅读（五）最终的核心

最新推荐文章于 2024-11-28 12:33:23 发布

原创最新推荐文章于 2024-11-28 12:33:23 发布 · 1k 阅读

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文章标签：

#callback #struct #button #structure #keyboard #events

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本文介绍了LiTE框架中的核心数据结构LiteBox，它是构建复杂控件的基础，并详细解释了其成员变量的功能，如事件处理回调等。

lite的代码写的很清晰，当然具体的实现我并没有一行行的代码看。

最重要的就是下面的结构体了，在每个控件的类型定义第一个总是它，当然第一也是有原因的。

/* @brief LiteBox structure
 * The LiteBox is the most common data structure in the LiTE framework.
 * It is used to build more complex widgets and compound structures.
 * Important event handling such as mouse and keyboard event handling
 * is handled in the various callbacks belonging to LiteBox.
 */
typedef struct _LiteBox {
  struct _LiteBox   *parent;            /**< Parent of the LiteBox */

  int                n_children;        /**< Num children in the child array */
  struct _LiteBox  **children;          /**< Child array */

  LiteBoxType        type;              /**< Type of LiteBox */

  DFBRectangle       rect;              /**< Rectangle of the LiteBox */
  IDirectFBSurface  *surface;           /**< LiteBox surface */

  DFBColor          *background;

  void              *user_data;         /**< User-provided data */

  int                is_focused;        /**< Indicates if the LiteBox is focused or not */
  int                is_visible;        /**< Indicates if the LiteBox is visible or not */
  int                is_active;         /**< Indicates if the LiteBox receives input or not */
  int                catches_all_events;/**< Indicates if the LiteBox prevents events from being handled by its children */
  int                handle_keys;       /**< Indicate if the LiteBox handles keyboard events */

  int  (*OnFocusIn)   (struct _LiteBox *self);                  /**< Focus-in callback */
  int  (*OnFocusOut)  (struct _LiteBox *self);                  /**< Focus-out callback  */

  int  (*OnEnter)     (struct _LiteBox *self, int x, int y);    /**< Enter callback */
  int  (*OnLeave)     (struct _LiteBox *self, int x, int y);    /**< Leave callback */
  int  (*OnMotion)    (struct _LiteBox *self, int x, int y,     /**< Motion callback */
                       DFBInputDeviceButtonMask buttons);
  int  (*OnButtonDown)(struct _LiteBox *self, int x, int y,
                       DFBInputDeviceButtonIdentifier button);  /**< Button down callback */
  int  (*OnButtonUp)  (struct _LiteBox *self, int x, int y,     /**< Button up callback */
                       DFBInputDeviceButtonIdentifier button);
  int  (*OnKeyDown)   (struct _LiteBox *self, DFBWindowEvent *evt); /**< Key down callback */
  int  (*OnKeyUp)     (struct _LiteBox *self, DFBWindowEvent *evt); /**< Key up callback */
  int  (*OnWheel)     (struct _LiteBox *self, DFBWindowEvent *evt); /**< Scroll wheel callback*/

  DFBResult (*Draw)      (struct _LiteBox *self, const DFBRegion *region, DFBBoolean clear); /**< Draw callback */
  DFBResult (*DrawAfter) (struct _LiteBox *self, const DFBRegion *region); /**< DrawAfter callback */
  DFBResult (*Destroy)   (struct _LiteBox *self);                  /**< Destroy callback */
} LiteBox;

也就是我们可以把任何一种控件的数据类型强制转换为LiteBox.

好了，最后就写到这里吧。说明比较少写，我想应该能看懂的。