In the cursor, a pixel called the hot spot marks the exact screen location that is affected by a mouse event, such as clicking a mouse button. Typically, the hot spot is the focal point of the cursor. The system tracks and recognizes this point as the position of the cursor. For example, typical hot spots are the pixel at the tip of an arrow-shaped cursor and the pixel in the middle of a crosshair-shaped cursor.
When a mouse input event occurs, the mouse driver translates the event into an appropriate mouse message that includes the coordinates of the hot spot. The system sends the mouse message to the window that contains the hot spot or to the window that is capturing mouse input. For more information, see Mouse Input.