GreMultiplyXforms

GreMultiplyXforms multiplies the transform matrix.

This function can be hooked by the presentation driver.


 * Simulation support: This function is simulated by a handling routine in the graphics engine.

Syntax
GreMultiplyXforms(hdc, paXform, paNewXformData, lMode, pInstance, lFunction)

Parameters

 * hdc (HDC) - input:Device context handle.
 * paXform (PXFORM) - output:On input: Transform used during lMode operation.
 * On output: Result of the lMode operation.


 * paNewXformData (PXFORM) - input:Transform used during lMode operation.
 * lMode (LONG) - input:Specifies how supplied array is used to set matrix:
 * SX_UNITY Set unity transform, ignore array values
 * SX_CAT_AFTER Concatenate after
 * SX_CAT_BEFORE Concatenate before
 * SX_OVERWRITE Overwrite


 * pInstance (PVOID) - input:Pointer to instance data.
 * lFunction (ULONG) - input:High-order WORD=flags; low-order WORD=NGreMultiplyXforms.

Return Code

 * fSuccess (BOOL) - returns:Return codes.
 * This function returns BOOLEAN (fSuccess).
 * TRUE Successful
 * FALSE Error
 * Possible Errors Detected: When an error is detected, the handling routine must call WinSetErrorInfo to post the condition. Error codes for conditions that the handling routine is expected to check include:
 * PMERR_INV_MATRIX_ELEMENT
 * PMERR_INV_TRANSFORM_TYPE
 * Refer to the "Error Explanations" section in the Presentation Manager Programming Reference for further explanation.

Remarks
This function multiplies the transform matrix (defined by paNewXformData) by the corresponding matrix in paXform. The result is stored in paXform. When this function is used to make a series of matrix multiplications on the same matrix, some loss of accuracy can occur due to rounding because no higher precision can be retained across calls.

Declaration

 * 1) define INCL_GRE_XFORMS
 * 2) include 

HDC      hdc;            /* Device context handle. */ PXFORM   paXform; PXFORM   paNewXformData; LONG     lMode;          /* Specifies how supplied array is used to set matrix: */ PVOID    pInstance;      /* Pointer to instance data. */ ULONG    lFunction; BOOL     fSuccess;       /* Return codes. */

fSuccess = GreMultiplyXforms(hdc, paXform, paNewXformData, lMode, pInstance, lFunction); 