Introduction - If you have any usage issues, please Google them yourself
In the mouse to move the process from the " starting point" should be " current position" to the mouse to draw a dynamic line drawing dynamic straight-line method, first delete the line, and then draw a straight in the mouse to move the process will continue received many WM_MOUSEMOVE message, which LOWORD (lParam) HIWORD (lParam) were stored mouse X, Y values