This function synthesizes mouse motion and button clicks.
At a Glance
| Header file: | Winuser.h |
| Windows CE versions: | 2.0 and later |
Syntax
VOID mouse_event(DWORD dwFlags, DWORD dx, DWORD dy,
DWORD dwData, DWORD dwExtraInfo );
Parameters
dwFlags
Specifies various aspects of mouse motion and button clicking. The bits in this parameter can be any reasonable combination of the following values:
| Value | Description |
| MOUSEEVENTF_ABSOLUTE | Specifies that the dx and dy parameters contain normalized absolute coordinates. If not set, those parameters contain relative data: the change in position since the last reported position. This flag can be set, or not set, regardless of what kind of mouse or mouse-like device, if any, is connected to the system. For further information about relative mouse motion, see the following Remarks section. |
| MOUSEEVENTF_MOVE | Specifies that movement occurred. |
| MOUSEEVENTF_LEFTDOWN | Specifies that the left button is down. |
| MOUSEEVENTF_LEFTUP | Specifies that the left button is up. |
| MOUSEEVENTF_RIGHTDOWN | Specifies that the right button is down. |
| MOUSEEVENTF_RIGHTUP | Specifies that the right button is up. |
| MOUSEEVENTF_MIDDLEDOWN | Specifies that the middle button is down. |
| MOUSEEVENTF_MIDDLEUP | Specifies that the middle button is up. |
dx
Specifies the mouse’s absolute position along the x-axis or its amount of motion since the last mouse event was generated, depending on the setting of MOUSEEVENTF_ABSOLUTE. Absolute data is given as the mouse’s actual x-coordinate; relative data is given as the number of mickeys moved. A mickey is the amount that a mouse has to move for it to report that it has moved.
dy
Specifies the mouse’s absolute position along the y-axis or its amount of motion since the last mouse event was generated, depending on the setting of MOUSEEVENTF_ABSOLUTE. Absolute data is given as the mouse’s actual y-coordinate; relative data is given as the number of mickeys moved.
dwData
If dwFlags is MOUSEEVENTF_WHEEL, then dwData specifies the amount of wheel movement. A positive value indicates that the wheel was rotated forward, away from the user; a negative value indicates that the wheel was rotated backward, toward the user. One wheel click is defined as WHEEL_DELTA, which is 120.
If dwFlags is not MOUSEEVENTF_WHEEL, then dwData should be zero.
dwExtraInfo
Unsupported.
Return Values
None.
Remarks
If the mouse has moved, indicated by MOUSEEVENTF_MOVE being set, dx and dy hold information about that motion. The information is given as absolute or relative integer values.
If MOUSEEVENTF_ABSOLUTE value is specified, dx and dy contain normalized absolute coordinates between 0 and 65,535. The event procedure maps these coordinates onto the display surface. Coordinate (0,0) maps onto the upper-left corner of the display surface, (65535,65535) maps onto the lower-right corner.
If the MOUSEEVENTF_ABSOLUTE value is not specified, dx and dy specify relative motions from when the last mouse event was generated (the last reported position). Positive values mean the mouse moved right (or down); negative values mean the mouse moved left (or up).
Relative mouse motion is subject to the settings for mouse speed and acceleration level. An end user sets these values using the Mouse control panel application. An application obtains and sets these values with the SystemParametersInfo function.
The system applies two tests to the specified relative mouse motion when applying acceleration. If the specified distance along either the x or y axis is greater than the first mouse threshold value, and the mouse acceleration level is not zero, the operating system doubles the distance. If the specified distance along either the x or y axis is greater than the second mouse threshold value, and the mouse acceleration level is equal to two, the operating system doubles the distance that resulted from applying the first threshold test. It is thus possible for the operating system to multiply relatively-specified mouse motion along the x or y axis by up to four times.
Once acceleration has been applied, the system scales the resultant value by the desired mouse speed. Mouse speed can range from 1 (slowest) to 20 (fastest) and represents how much the pointer moves based on the distance the mouse moves. The default value is 10, which results in no additional modification to the mouse motion.
See Also