GetImagePointer

Description

This COM method returns the pointer to the pixel at the specified coordinates of an image.


Syntax

[VB]
Value=objImageWarp.GetImagePointer( Inp, X, Y )

[C/C++]
HRESULT GetImagePointer( int Inp, int X, int Y, VARIANT* pValue );


Parameters [C/C++]

X [in]

The x-coordinate of the pixel

Y [in]

The y-coordinate of the pixel

pValue [out,retval]

Pointer to the specified memory location

Return Values

S_OK

Success

E_FAIL

Failure.

Example

This C++ example grabs a frame, retrieves a pointer to the 32th line in the frame memory and copies the pixels values into a byte array . A wrapper class CImageWarp is used to access the COM object :

BYTE line[4096];
int iWidth=m_ImageWarp.GetSizeX;
m_ImageWarp.Call("grabim(1))
While IW.Status <> SS_IDLE
Wend
BYTE* ptr=m_ImageWarp.GetImagePointer(1,0,32);
memcpy(&line,v.pcVal,iWidth);

Remarks

The GetImagePointer method provides the most efficient way to quickly access the content of ImageWarp images in pointer-aware programming languages. Unlike GetImageArray, this method doesn't modify original pixel values of high-bit depth images. The number of bytes in each line of the image buffer depends on the format and horizontal size of the video as specified in the following table:

Format	Line width in bytes
8-bit monochrome	SizeX
16-bit gray monochrome	SizeX * 2
32-bit gray monochrome	SizeX * 4
float	SizeX * 4
complex	SizeX * 8
24-bit RGB	SizeX * 3
32-bit RGB	SizeX * 4
48-bit RGB	SizeX * 6