| #define MOUSETRAILS 39 |
| WORD Control(lpDestDevice, MOUSETRAILS, lpTrailSize, NULL) | |||
| LPPDEVICE lpDestDevice; | |||
| LPINT lpTrailSize; |
The MOUSETRAILS escape enables or disables mouse trails for the display driver.
lpDestDevice
Points to a PDEVICE structure specifying the destination device.
lpTrailSize
Points to a 16-bit variable containing a value specifying the action to take, and the number of mouse cursor images to display (trail size). The variable can be one of the following values.
| Value | Meaning |
| 1 through 7 | Enables mouse trails and sets the trail size to the specified number. A value of 1 requests a single mouse cursor; 2 requests that one extra mouse cursor be drawn behind the current mouse cursor, and so on, up to a maximum of 7 total cursor images. The function sets the MouseTrails setting in the WIN.INI file to the given value. The function then returns the new trail size. |
| 0 | Disables mouse trails. The function sets the MouseTrails setting to the negative value of the current trail size (if positive). The function then returns the negative value. |
| -1 | Enables mouse trails. The display driver reads the MouseTrails setting from the [Windows] section of the WIN.INI file. If the setting value is positive, the function sets the trail size to the given value. If the setting value is negative, the function sets trail size to the setting's absolute value and writes the positive value back to WIN.INI. If the MouseTrails setting is not found, the function sets the trail size to 7 and writes a new MouseTrails setting to the WIN.INI file, setting its value to 7. The function then returns the new trail size. |
| -2 | Disables mouse trails but does not cause the driver to update the WIN.INI file. |
| -3 | Enables mouse trails but does not cause the driver to update the WIN.INI file. |
The return value specifies the size of the escape if successful. Otherwise, it is zero if the escape is not supported.
An application can retrieve the current trail size by calling the QUERYESCSUPPORT escape as shown in the following example:
Escape(hDC, QUERYESCSUPPORT, sizeof(int), MOUSETRAILS, NULL);
The QUERYESCSUPPORT escape returns the current trail size without changing to the current setting. If the escape returns zero, mouse trails are not supported by the display driver. If the escape returns a positive value, mouse trails are enabled and the value specifies the current trail size. If the escape returns a negative value, mouse trails are currently disabled and the value is the same as the negative MouseTrails value specified in the WIN.INI file.