windows绝对坐标一些官方说明

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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; coordinate (65535,65535) maps onto the lower-right corner. In a multimonitor system, the coordinates map to the primary monitor.

If MOUSEEVENTF_VIRTUALDESK is specified, the coordinates map to the entire virtual desktop.

If the MOUSEEVENTF_ABSOLUTE value is not specified, dxand dy specify movement relative to the previous mouse event (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 effects of the mouse speed and the two-mouse threshold values. A user sets these three values with the Pointer Speed slider of the Control Panel’s Mouse Properties sheet. You can obtain and set these values using the SystemParametersInfo function.

The system applies two tests to the specified relative mouse movement. If the specified distance along either the x or y axis is greater than the first mouse threshold value, and the mouse speed is not zero, the 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 speed is equal to two, the system doubles the distance that resulted from applying the first threshold test. It is thus possible for the system to multiply specified relative mouse movement along the x or y axis by up to four times.

鼠标移动速度属性设置
SPI_SETMOUSESPEED
0x0071
Sets the current mouse speed. The pvParam parameter is an integer between 1 (slowest) and 20 (fastest). A value of 10 is the default. This value is typically set using the mouse control panel application.

10 - 不加速 20- 加速到2倍 1- 减慢到1/2 ?

SPI_SETMOUSE
0x0004
Sets the two mouse threshold values and the mouse acceleration. The pvParam parameter must point to an array of three integers that specifies these values. See mouse_event for further information.

上面说的两个阈值，第三个加速是啥？难道是SPI_SETMOUSESPEED的值？
在win10系统亲测，第三个值是是否勾选提高鼠标精度。0禁用提高鼠标精度，1开启提高鼠标精度，msdn最后的示例程序，成功误导了我们