GreSetWindowViewportXform

GreSetWindowViewportXform sets the window or viewport transform matrix elements as specified.

This function can be hooked by the presentation driver.

Simulation support

This function is simulated by a handling routine in the graphics engine.

Syntax

GreSetWindowViewportXform(hdc, paXformData, flOptions, pInstance, lFunction);

Parameters

hdc (HDC) - input

Device context handle.

paXformData (PXFORM) - input

Pointer to an array.

Pointer to an array of six matrix elements for two-dimensional formation. These are M11, M12, M21, M22, M41, and M42.

flOptions (LONG) - input

Specifies how the supplied array should be used to set the matrix.

Valid values are:

• 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=NGreSetWindowViewportXform.

Returns

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_BASE_ERROR
• PMERR_COORDINATE_OVERFLOW
• PMERR_DEV_FUNC_NOT_INSTALLED
• PMERR_HDC_BUSY
• PMERR_INSUFFICIENT_MEMORY
• PMERR_INV_COORD_SPACE
• PMERR_INV_COORDINATE
• PMERR_INV_HDC
• PMERR_INV_HRGN
• PMERR_INV_IN_AREA
• PMERR_INV_IN_PATH
• PMERR_INV_LENGTH_OR_COUNT
• PMERR_INV_MATRIX_ELEMENT
• PMERR_INV_PATTERN_REF_PT_ATTR
• PMERR_INV_PICK_APERTURE_POSN
• PMERR_INV_RECT
• PMERR_INV_REGION_CONTROL
• PMERR_INV_TRANSFORM_TYPE
• PMERR_PATH_LIMIT_EXCEEDED

Refer to the "Error Explanations" section in the Presentation Manager Programming Reference for further explanation.

Sample

#define INCL_GRE_XFORMS
#include <os2.h>

HDC       hdc;          /*  Device context handle. */
PXFORM    paXformData;  /*  Pointer to an array. */
LONG      flOptions;    /*  Specifies how the supplied array should be used to set the matrix. */
PVOID     pInstance;    /*  Pointer to instance data. */
ULONG     lFunction;    /*  High-order WORD=flags; low-order WORD=NGreSetWindowViewportXform. */
BOOL      fSuccess;     /*  Return codes. */

fSuccess = GreSetWindowViewportXform(hdc,
             paXformData, flOptions, pInstance,
             lFunction);