## Presentation Device Driver Reference for OS/2

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### GreRectVisible

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    Syntax
    Parameters
    Returns
    Glossary

Simulation support:

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

Description

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.

    #define INCL_GRE_CLIP

    #include <os2.h>

    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);