GreCombineRectRegion

GreCombineRectRegion combines a region with a rectangle to make a new region. If COM_TRANSFORM is not set, the function expects the point to be in device coordinates. The destination region can be the same as the source region. An error is raised if either of the regions specified is currently selected as the clip region. The source and destination regions must be of the same device class.

This function can be hooked by the presentation driver.

Simulation support

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

Syntax

GreCombineRectRegion(hdc, hrgnDst, prclRect, hrgnSrc, cmdMode, pInstance, lFunction);

Parameters

hdc (HDC) - input

Device context handle.

hrgnDst (HRGN) - input

Destination region handle.

prclRect (PRECTL) - input

Pointer to rectangle.

hrgnSrc (HRGN) - input

Region handle.

cmdMode (LONG) - input

Method of combination.

CRGN_OR

Union of hrgnSrc and prclRect.

CRGN_COPY

Uses prclRect only. The hrgnSrc parameter is ignored.

CRGN_XOR

Symmetric difference of hrgnSrc and prclRect.

CRGN_AND

Intersection of hrgnSrc and prclRect.

CRGN_DIFF

Uses hrgnSrc and not (prclRect).

pInstance (PVOID) - input

Pointer to instance data.

lFunction (ULONG) - input

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

Returns

rc (LONG) - returns

This function returns an integer (lComplexity) indicating the complexity of the new region:

• RGN_ERROR

Error

• RGN_NULL

Null region

• RGN_RECT

Rectangular region

• RGN_COMPLEX

Complex region (more than one rectangle)

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_HRGN_BUSY
• PMERR_INSUFFICIENT_MEMORY
• PMERR_INV_COORDINATE
• PMERR_INV_HRGN
• PMERR_INV_RECT
• PMERR_INV_REGION_MIX_MODE
• PMERR_REGION_IS_CLIP_REGION

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

Sample

#define INCL_GRE_REGIONS
#include <os2.h>

HDC       hdc;        /*  Device context handle. */
HRGN      hrgnDst;    /*  Destination region handle. */
PRECTL    prclRect;   /*  Pointer to rectangle. */
HRGN      hrgnSrc;    /*  Region handle. */
LONG      cmdMode;    /*  Method of combination. */
PVOID     pInstance;  /*  Pointer to instance data. */
ULONG     lFunction;  /*  High-order WORD=flags; low-order WORD=NGreCombineRectRegion. */
LONG      rc;

rc = GreCombineRectRegion(hdc, hrgnDst, prclRect, hrgnSrc, cmdMode, pInstance, lFunction);