GreSetPageViewport

GreSetPageViewport name field sets the page viewport in device coordinates so that the graphics engine can update the device transform by using the page window and page viewport coordinates.

This function can be hooked by the presentation driver.

Simulation support

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

Syntax

 GreSetPageViewport(hdc, prclViewport, flOptions, pInstance, lFunction);

Parameters

hdc (HDC) - input

Device context handle.

prclViewport (PRECTL) - input

Pointer to page viewport boundaries in device coordinates.

RECTL structure:

• xLeft Minimum x-coordinate of viewport
• yBottom Minimum y-coordinate
• xRight Maximum x-coordinate of viewport
• yTop Maximum y-coordinate

flOptions (ULONG) - input

Reserved parameter. The only valid value is 0.

pInstance (PVOID) - input

Pointer to instance data.

lFunction (ULONG) - input

High-order WORD=flags; low-order WORD=NGreSetPageViewport.

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_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_PAGE_VIEWPORT
• PMERR_INV_PATTERN_REF_PT_ATTR
• PMERR_INV_PICK_APERTURE_POSN
• PMERR_INV_RECT
• PMERR_INV_REGION_CONTROL
• PMERR_INV_SET_VIEWPORT_OPTION
• PMERR_PATH_LIMIT_EXCEEDED

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

Sample Code

#define INCL_GRE_XFORMS
#include <os2.h>

HDC       hdc;           /*  Device context handle. */
PRECTL    prclViewport;  /*  Pointer to page viewport boundaries in device coordinates. */
ULONG     flOptions;     /*  Reserved parameter.  The only valid value is 0. */
PVOID     pInstance;     /*  Pointer to instance data. */
ULONG     lFunction;     /*  High-order WORD=flags; low-order WORD=NGreSetPageViewport. */
BOOL      fSuccess;      /*  Return codes. */

fSuccess = GreSetPageViewport(hdc, prclViewport,
             flOptions, pInstance, lFunction);