GreRectVisible

GreRectVisible checks whether any part of the given rectangle is visible within the DC region. The DC region is the intersection of the application clipping and the window clipping.

This function can be hooked by the presentation driver.


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

Syntax
GreRectVisible(hdc, prclRect, pInstance, lFunction);

Parameters

 * hdc (HDC) - input
 * Device context handle.


 * prclRect (PRECTL) - input
 * Pointer to rectangle in world or screen coordinates. RECTL structure:


 * xLeft Minimum x-coordinate of rectangle
 * yBottom Minimum y-coordinate
 * xRight Maximum x-coordinate of rectangle
 * yTop Maximum y-coordinate


 * pInstance (PVOID) - input
 * Pointer to instance data.


 * lFunction (ULONG) - input
 * High-order WORD=flags; low-order WORD=NGreRectVisible.

Return Code

 * rc (LONG) - returns
 * Return codes.


 * This function returns an integer (lVisible) indicating the visibility of the rectangle.


 * RVIS_ERROR Error
 * RVIS_INVISIBLE Not visible
 * RVIS_PARTIAL Partially visible
 * RVIS_VISIBLE All visible


 * 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_INV_COORD_SPACE
 * PMERR_INV_COORDINATE
 * PMERR_INV_HDC
 * PMERR_INV_LENGTH_OR_COUNT
 * PMERR_INV_RECT


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

Declaration

 * 1) define INCL_GRE_CLIP
 * 2) include 

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

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