GreConvert

GreConvert converts the specified coordinates from one coordinate space to another by using the current values of the transforms.

This function can be hooked by the presentation driver.

Simulation support

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

Syntax

GreConvert(hdc, lSrc, lDst, paptlPoint, cPoints, pInstance, lFunction);

Parameters

hdc (HDC) - input

Device context handle.

lSrc (LONG) - input

Source-coordinate space.

CVTC_WORLD

World-coordinate space

CVTC_MODEL

Model space

CVTC_DEFAULTPAGE

Default page-coordinate space

CVTC_PAGE

Page-coordinate space

CVTC_DEVICE

Device-coordinate space. Screen coordinates are 32-bit signed integers and are used by the presentation driver as screen pel addresses.

lDst (LONG) - input

Target-coordinate space. Defined by the same values as lSrc.

paptlPoint (PPOINTL) - input

Pointer to array of (x, y) coordinates to transform. The result is also returned to this parameter.

cPoints (LONG) - input

Count of coordinate pairs in the array.

pInstance (PVOID) - input

Pointer to instance data.

lFunction (ULONG) - input

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

Returns

fSuccess (BOOL) - returns

This function returns BOOLEAN (fSuccess).

TRUE

Successful

FALSE

Error

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_HDC_BUSY
• PMERR_INV_COORD_SPACE
• PMERR_INV_HDC
• PMERR_INV_LENGTH_OR_COUNT

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

Sample

#define INCL_GRE_XFORMS
#include <os2.h>

HDC        hdc;         /*  Device context handle. */
LONG       lSrc;        /*  Source-coordinate space. */
LONG       lDst;        /*  Target-coordinate space.  Defined by the same values as lSrc. */
PPOINTL    paptlPoint;
LONG       cPoints;     /*  Count of coordinate pairs in the array. */
PVOID      pInstance;   /*  Pointer to instance data. */
ULONG      lFunction;   /*  High-order WORD=flags; low-order WORD=NGreConvert. */
BOOL       fSuccess;    /*  This function returns BOOLEAN (fSuccess). */

fSuccess = GreConvert(hdc, lSrc, lDst, paptlPoint,
             cPoints, pInstance, lFunction);