emwin 消息ID是怎样定义的

Eleven

emwin 回调函数中的这些消息ID是依据什么定义的，它们和回调函数在哪里发生的联系，为什么回调函数swich选择中会识别它，感觉它们是凭空产生的。
如果自己想定义一个消息应该怎样定义呢，怎样才定义呢，回调函数swich才会识别它呢

/*********************************************************************
*
*       Messages Ids
*
* The following is the list of windows messages.
*/
#define WM_CREATE                   0x0001  /* The first message received, right after client has actually been created */
#define WM_MOVE                     0x0003  /* window has been moved (Same as WIN32) */

#define WM_SIZE                     0x0005  /* Is sent to a window after its size has changed (Same as WIN32, do not change !) */

#define WM_DELETE                   11      /* Delete (Destroy) command: This tells the client to free its data strutures since the window
                                               it is associates with no longer exists.*/
#define WM_TOUCH                    12      /* Touch screen message */
#define WM_TOUCH_CHILD              13      /* Touch screen message to ancestors */
#define WM_KEY                      14      /* Key has been pressed */

#define WM_PAINT                    0x000F  /* Repaint window (because content is (partially) invalid */

#if GUI_SUPPORT_MOUSE
#define WM_MOUSEOVER                16      /* Mouse has moved, no key pressed */
#define WM_MOUSEOVER_END            18      /* Mouse has moved, no key pressed */
#endif

#define WM_PID_STATE_CHANGED        17      /* Pointer input device state has changed */

#define WM_GET_INSIDE_RECT          20      /* get inside rectangle: client rectangle minus pixels lost to effect */
#define WM_GET_ID                   21      /* Get id of widget */
#define WM_SET_ID                   22      /* Set id of widget */
#define WM_GET_CLIENT_WINDOW        23      /* Get window handle of client window. Default is the same as window */
#define WM_CAPTURE_RELEASED         24      /* Let window know that mouse capture is over */

#define WM_INIT_DIALOG              29      /* Inform dialog that it is ready for init */

#define WM_SET_FOCUS                30      /* Inform window that it has gotten or lost the focus */
#define WM_GET_ACCEPT_FOCUS         31      /* Find out if window can accept the focus */
#define WM_NOTIFY_CHILD_HAS_FOCUS   32      /* Sent to parent when child receives / loses focus */

#define WM_NOTIFY_OWNER_KEY         33      /* Some widgets (e.g. listbox) notify owner when receiving key messages */

#define WM_GET_BKCOLOR              34      /* Return back ground color (only frame window and similar) */
#define WM_GET_SCROLL_STATE         35      /* Query state of scroll bar */

#define WM_SET_SCROLL_STATE         36      /* Set scroll info ... only effective for scrollbars */

#define WM_NOTIFY_CLIENTCHANGE      37      /* Client area may have changed */
#define WM_NOTIFY_PARENT            38      /* Notify parent. Information is detailed as notification code */
#define WM_NOTIFY_PARENT_REFLECTION 39      /* Notify parent reflection.
                                               Sometimes send back as a result of the WM_NOTIFY_PARENT message
                                               to let child react on behalf of its parent.
                                               Information is detailed as notification code */
#define WM_NOTIFY_ENABLE            40      /* Enable or disable widget */
#define WM_NOTIFY_VIS_CHANGED       41      /* Visibility of a window has or may have changed */

#define WM_HANDLE_DIALOG_STATUS     42      /* Set or get dialog status */
#define WM_GET_RADIOGROUP           43      /* Send to all siblings and children of a radio control when
                                               selection changed */
#define WM_MENU                     44      /* Send to owner window of menu widget */
#define WM_SCREENSIZE_CHANGED       45      /* Send to all windows when size of screen has changed */
#define WM_PRE_PAINT                46      /* Send to a window before it receives a WM_PAINT message */
#define WM_POST_PAINT               47      /* Send to a window after (the last) WM_PAINT message */

#define WM_MOTION                   48      /* Automatic motion messages */

#define WM_TIMER                    0x0113  /* Timer has expired              (Keep the same as WIN32) */
#define WM_WIDGET                   0x0300  /* 256 messages reserved for Widget messages */
#define WM_USER                     0x0400  /* Reserved for user messages ... (Keep the same as WIN32) */

/*********************************************************************

flyleaf

这是emwin内部定义的消息，不是我们定义的，要想知道得找到emwin源码了