LockPixels

LockPixels Lock the offscreen buffer in memory for duration of a draw

#include <QDOff screen.h Graphics Devices

PixMapHandle pm ; Pixel map handle returned from a

returns boolean, 0 if buffer has moved (error state)

LockPixels should be called before drawing to or from an offscreen graphics

world. In the pm parameter pass the pixel map handle returned from a

GetGWorldPixMap call. LockPixels locks the offscreen buffer in memory

for the duration of the drawing.

If the offscreen buffer is purgeable and has been purged, LockPixels

returns FALSE to signal that no drawing can be made to the buffer memory. At

that point, the application should either call UpdateGWorld to reallocate the

buffer or draw directly in the window it represents.

If the offscreen buffer hasn't been purged or is not purgeable, LockPixels

returns TRUE.

As soon as the drawing is completed, you should call UnlockPixels.

Returns: a Boolean value; It will be one of:

TRUE buffer is in memory (either not purged or not purgeable)

FALSE buffer has been purged