GreExcludeClipRectangle

GreExcludeClipRectangle excludes the specified rectangle from the clipping region, that is, the area covered by the rectangle will be outside the resulting clip region. If COM_TRANSFORM is not set, the function expects the rectangle points to be in device coordinates. GreExcludeClipRectangle creates a clip region when none exists. The application is responsible for deleting this clip region when it is finished. Otherwise, it is not deleted until the DC is closed.

This function can be hooked by the presentation driver.

Simulation support

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

Syntax

GreExcludeClipRectangle(hdc, prclRect, pInstance, lFunction);

Parameters

hdc (HDC) - input

Device context handle.

prclRect (PRECTL) - input

Pointer to rectangle in world or device coordinates.

RECTL structure:

xLeft Minimum x-coordinate of rectangle

yBottom Minimum y-coordinate

xRight Maximum x-coordinate of rectangle

yTop Maximum y-coordinate

All the boundaries of this rectangle are considered to be part of the interior and are clipped accordingly.

pInstance (PVOID) - input

Pointer to instance data.

lFunction (ULONG) - input

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

Returns

rc (LONG) - returns

Return codes.

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

• RGN_ERROR Error
• RGN_NULL Null region
• RGN_RECT Rectangular region
• RGN_COMPLEX Complex region (more than 1 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_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_RECT
• PMERR_INV_REGION_CONTROL

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

Sample

#define INCL_GRE_CLIP
#include <os2.h>

HDC       hdc;        /*  Device context handle. */
PRECTL    prclRect;   /*  Pointer to rectangle in world or device coordinates. */
PVOID     pInstance;  /*  Pointer to instance data. */
ULONG     lFunction;  /*  High-order WORD=flags; low-order  WORD=NGreExcludeClipRectangle. */
LONG      rc;         /*  Return codes. */

rc = GreExcludeClipRectangle(hdc, prclRect,
       pInstance, lFunction);