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# FALCON/EAGLE user manual 4.62

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is_LockDDOverlayMem | Scroll Previous Top Next More

Syntax

INT is_LockDDOverlayMem(HIDS hf, void** ppMem, INT* pPitch)

Description

In DirectDraw mode is_LockDDOverlayMem() gives access to the image memory and returns the address pointer to the beginning of the image memory. And thus the overlay buffer can be directly written to, without having to use the Windows GDI functions. pPitch returns the line offset in bytes from the beginning of one line to the beginning of the following line. Access must be disabled as soon as possible with the is_UnlockDDOverlayMem() function. Within a LockDDMem – UnlockDDMem block there are no updates of the back buffer on the display.

Parameters

hf | Frame grabber handle
ppMem | Pointer to variable, which will contain address pointer
pPitch | Pointer to variable, which will contain the pitch value

Return value

IS_SUCCESS, IS_NO_SUCCESS

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