In Windows 3.1, display drivers can improve mouse cursor visibility by supporting mouse trails. A mouse trail is a sequence of two or more cursor images that mark current and previous mouse cursor positions. A display driver creates a mouse trail by drawing a cursor at each new mouse position and leaving additional cursors at previous positions. The driver delays erasing the previous cursors until a specified number of cursors are visible.
A display driver provides support for mouse trails by processing the MOUSE-TRAILS escape in its Control function. The MOUSETRAILS escape enables or disables mouse trails. It also sets the maximum number of cursors to be displayed in the trail. The display driver must also process the QUERYESCSUPPORT escape, returning the status of the mouse trails if the requested escape is MOUSETRAILS.
The display driver draws the mouse trail when it processes the MoveCursor function. Any trailing cursors must have the same shape as the current cursor. The display driver should provide mouse trails for system cursors, such as the pointer, I-beam, and hourglass, and for application-specific cursor as well.
The display driver is responsible for recording the mouse trail status by maintaining the MouseTrails setting in the [Windows] section of the WIN.INI file. The driver sets this setting to a positive value to indicate that the mouse trails are enabled. The value also specifies the number of cursors to display. The driver sets this setting to a negative value when the mouse trails are disabled. The absolute value specifies the number of cursors to display prior to being disabled.
Users can turn mouse trails on or off by using the Windows 3.1 Control Panel. The mouse settings dialog box displays a Mouse Trails option.
Applications should not enable or disable mouse trails. However, third-party mouse configuration programs should enable or disable mouse trails.