send_mouse_down_eventT_send_mouse_down_eventSendMouseDownEventSendMouseDownEventsend_mouse_down_event (算子)

名称

send_mouse_down_eventT_send_mouse_down_eventSendMouseDownEventSendMouseDownEventsend_mouse_down_event — 向窗口缓冲区发送事件，表示鼠标按下事件。

签名

描述

send_mouse_down_eventsend_mouse_down_eventSendMouseDownEventSendMouseDownEventSendMouseDownEventsend_mouse_down_event sends an event at the position (RowRowRowRowrowrow, ColumnColumnColumnColumncolumncolumn) to the buffer window WindowHandleWindowHandleWindowHandleWindowHandlewindowHandlewindow_handle, signaling that the mouse button encoded by ButtonButtonButtonButtonbuttonbutton has been pressed. Please refer to get_mbuttonget_mbuttonGetMbuttonGetMbuttonGetMbuttonget_mbutton to see how to encode ButtonButtonButtonButtonbuttonbutton。

The purpose of this operator is to manipulate drawing objects in a buffer window. If the coordinates RowRowRowRowrowrow and ColumnColumnColumnColumncolumncolumn are pointing on a drawing object, it is activated and can be moved or changed by sending more events with the send_mouse_down_eventsend_mouse_down_eventSendMouseDownEventSendMouseDownEventSendMouseDownEventsend_mouse_down_event operator. To simplify the interaction with the drawing object, the coordinates RowRowRowRowrowrow and ColumnColumnColumnColumncolumncolumn are given in the image coordinate system. To convert window coordinates into image coordinates, the operator convert_coordinates_window_to_imageconvert_coordinates_window_to_imageConvertCoordinatesWindowToImageConvertCoordinatesWindowToImageConvertCoordinatesWindowToImageconvert_coordinates_window_to_image can be used.

If the event could be processed, send_mouse_down_eventsend_mouse_down_eventSendMouseDownEventSendMouseDownEventSendMouseDownEventsend_mouse_down_event returns 'true'"true""true""true""true""true" in ProcessedProcessedProcessedProcessedprocessedprocessed. If no action for the event could be determined (e.g., because there is no drawing object below the mouse position), 'false'"false""false""false""false""false" is returned in ProcessedProcessedProcessedProcessedprocessedprocessed. In this case the caller may determine an action for the event.

The operators send_mouse_down_eventsend_mouse_down_eventSendMouseDownEventSendMouseDownEventSendMouseDownEventsend_mouse_down_event, send_mouse_up_eventsend_mouse_up_eventSendMouseUpEventSendMouseUpEventSendMouseUpEventsend_mouse_up_event, send_mouse_drag_eventsend_mouse_drag_eventSendMouseDragEventSendMouseDragEventSendMouseDragEventsend_mouse_drag_event and send_mouse_double_click_eventsend_mouse_double_click_eventSendMouseDoubleClickEventSendMouseDoubleClickEventSendMouseDoubleClickEventsend_mouse_double_click_event are the only means to manipulate drawing objects in buffer windows.

注意

send_mouse_down_eventsend_mouse_down_eventSendMouseDownEventSendMouseDownEventSendMouseDownEventsend_mouse_down_event 依赖于 libcanvas 库，该库在嵌入式系统上可能不可用。

执行信息

• 多线程类型：可重入（与非独占算子并行运行）。
• 多线程作用域：全局（可从任何线程调用）。
• 未采用并行化处理。

参数

结果

send_mouse_down_eventsend_mouse_down_eventSendMouseDownEventSendMouseDownEventSendMouseDownEventsend_mouse_down_event 返回值 2 ( H_MSG_TRUE) if the window handle WindowHandleWindowHandleWindowHandleWindowHandlewindowHandlewindow_handle corresponds to a window of valid type, and the event is properly encoded.否则，将抛出异常。

可能的前趋

open_windowopen_windowOpenWindowOpenWindowOpenWindowopen_window

另见

send_mouse_up_eventsend_mouse_up_eventSendMouseUpEventSendMouseUpEventSendMouseUpEventsend_mouse_up_event, send_mouse_double_click_eventsend_mouse_double_click_eventSendMouseDoubleClickEventSendMouseDoubleClickEventSendMouseDoubleClickEventsend_mouse_double_click_event, open_windowopen_windowOpenWindowOpenWindowOpenWindowopen_window

模块

基础