GreGetRegionBox

GreGetRegionBox loads the buffer pointed to by prclRect with the dimensions of the tightest rectangle around the region indicated by hrgn. Note that the rectangle is always returned in device coordinates. GreGetRegionBox raises an error when hrgn is the handle of the currently selected clip region.

This function can be hooked by the presentation driver.


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

Syntax
GreGetRegionBox(hdc, hrgn, prclRect, pInstance, lFunction)

Parameters

 * hdc (HDC) - input:Device context handle.
 * hrgn (HRGN) - input:Region handle.
 * prclRect (PRECTL) - input:Pointer to rectangle in device coordinates.
 * pInstance (PVOID) - input:Pointer to instance data.
 * lFunction (ULONG) - input:High-order WORD=flags; low-order WORD=NGreGetRegionBox.

Returns

 * rc (LONG) - returns:Return codes.
 * This function returns an integer (lComplexity) indicating the complexity of the 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_HRGN_BUSY
 * PMERR_INV_HRGN
 * PMERR_REGION_IS_CLIP_REGION
 * Refer to the "Error Explanations" section in the Presentation Manager Programming Reference for further explanation.

Sample

 * 1) define INCL_GRE_REGIONS
 * 2) include 

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

rc = GreGetRegionBox(hdc, hrgn, prclRect, pInstance, lFunction);

Remarks
When the region is empty, the rectangle is returned with the right boundary equal to the left, and the top boundary equal to the bottom. GreGetRegionBox must return an error when the region indicated by hrgn is selected into the DC as a clip region.