GpiSetStopDraw

This function sets or clears the "stop draw" condition.

Syntax

GpiSetStopDraw(hps, lValue);

Parameters

hps (HPS) - input

Presentation-space handle.

lValue (LONG) - input

Stop draw condition.

SDW_OFF

Clear the "stop draw" condition

SDW_ON

Set the "stop draw" condition.

Returns

rc (BOOL) - returns

Success indicator.

TRUE

Successful completion

FALSE

Error occurred.

Errors

Possible returns from WinGetLastError

PMERR_INV_HPS (0x207F)

An invalid presentation-space handle was specified.

PMERR_INV_STOP_DRAW_VALUE (0x20CF)

An invalid value parameter was specified with GpiSetStopDraw.

PMERR_INV_MICROPS_FUNCTION (0x20A1)

An attempt was made to issue a function that is invalid in a micro presentation space.

Remarks

This function allows an application to set up, and control, an asynchronous thread on which long drawing operations may be performed. At the point at which the controlling thread stops a draw, it sets the "stop draw" condition. The controlling thread clears this condition after it has received an acknowledgment from the drawing thread.

The "stop draw" condition has no effect on any other calls.

If one of the following calls is made (or has already been initiated from another thread) to the same presentation space, the call is terminated if the "stop draw" condition exists:

• GpiDrawChain
• GpiDrawDynamics
• GpiDrawFrom
• GpiDrawSegment
• GpiPlayMetaFile
• GpiPutData.

The call terminates with a warning.

Any call other than GpiSetStopDraw, directed at a presentation space that is currently in use, gives a PMERR_PS_BUSY error condition.

Note: If this function is issued when an asynchronous draw to a metafile is taking place, the result is an unusable metafile.

Example Code

#define INCL_GPICONTROL /* Or use INCL_GPI, INCL_PM, */
#include <os2.h>

HPS     hps;     /*  Presentation-space handle. */
LONG    lValue;  /*  Stop draw condition. */
BOOL    rc;      /*  Success indicator. */

rc = GpiSetStopDraw(hps, lValue);

This example shows how to stop drawing.

 

#define INCL_GPICONTROL
#include <OS2.H>
HPS hps;         /*   Presentation-space */
                 /*   handle.            */

GpiSetStopDraw(hps,SDW_OFF);

Related Functions

• GpiDrawChain
• GpiDrawDynamics
• GpiDrawFrom
• GpiDrawSegment
• GpiPlayMetaFile
• GpiPutData
• GpiQueryStopDraw