==== MouSetScaleFact ====

**Bindings**: [[setscalefact#C bindings|C]], [[setscalefact#MASM bindings|MASM]]

This call assigns to the current mouse device driver a new pair of 1-word scaling factors. 

//MouSetScaleFact// (ScaleStruct, DeviceHandle) 

//ScaleStruct// (**PSCALEFACT**) - input 
Address of the control block structure that contains the current row and column coordinate scaling factors. The scaling factors must be greater than or equal to 1 and less than or equal to (32K - 1). 

//rowscale// (**USHORT**) 
Row scaling factor. 

//colscale// (**USHORT**) 
Column scaling factor. 

**DeviceHandle** (**HMOU**) - input 
Handle of the mouse device from a previous MouOpen. 

//rc// (**USHORT**) - return 
Return code descriptions are: 

|0 |NO_ERROR |
|385 |ERROR_MOUSE_NO_DEVICE |
|387 |ERROR_MOUSE_INV_PARMS |
|466 |ERROR_MOU_DETACHED |
|501 |ERROR_MOUSE_NO_CONSOLE |
|505 |ERROR_MOU_EXTENDED_SG |

**Remarks** 

[[en:ibm:prcp:mou:setscalefact|MouSetScaleFact]] sets the mickey-to-pixel ratio for mouse motion. The row scale and column scale ratios specify a number of mickeys for each 8 pixels. The default value for the row scale is 16 mickeys for each 8 pixels. The default value for the column scale is 8 mickeys to 8 pixels. 

The number of pixels moved does not have to correspond 1-to-1 with the number of mickeys the mouse moves. The scaling factor defines a sensitivity for the mouse that is a ratio of the number of mickeys required to move the cursor 8 pixels on the screen. The sensitivity determines at what rate the cursor moves on the screen. 

=== C bindings ===

<code c>
typedef struct _SCALEFACT {   /* mousc */
  USHORT rowScale;            /* row scaling factor */
  USHORT colScale;            /* column coordinate scaling factor */
} SCALEFACT;

#define INCL_MOU

USHORT  rc = MouSetScaleFact(ScaleStruct, DeviceHandle);

PSCALEFACT       ScaleStruct;   /* 2-word structure */
HMOU             DeviceHandle;  /* Mouse device handle */

USHORT           rc;            /* return code */
</code>

=== MASM bindings ===

<code asm>
SCALEFACT struc
  mousc_rowScale  dw  ? ;row scaling factor
  mousc_colScale  dw  ? ;column coordinate scaling factor
SCALEFACT ends

EXTRN  MouSetScaleFact:FAR
INCL_MOU            EQU 1

PUSH@  OTHER   ScaleStruct   ;2-word structure
PUSH   WORD    DeviceHandle  ;Mouse device handle
CALL   MouSetScaleFact

Returns WORD
</code>