LDicomDS::GetOverlayAttributes

#include "ltdic.h"

L_UINT16 LDicomDS::GetOverlayAttributes(uOverlayIndex, pOverlayAttributes,uStructSize, pGroupNumber, pIsOverlayInDataset, uFlags)

L_UINT uOverlayIndex;	/* index */
pOVERLAYATTRIBUTES pOverlayAttributes;	/* pointer to a structure */
L_UINT uStructSize;	/* size of a structure */
L_INT * pGroupNumber;	/* group number */
L_BOOL * pIsOverlayInDataset;	/* pointer to a variable */
L_UINT uFlags;	/* reserved for future use */

Retrieves the attributes of the overlay at the specified index.

Parameter	Description
uOverlayIndex	The index of the overlay for which to get the attributes.
pOverlayAttributes	Pointer to a structure to be updated with the overlay attributes.
uStructSize	Size of the OVERLAYATTRIBUTES structure. Pass sizeof(OVERLAYATTRIBUTES).
pGroupNumber	Pointer to a variable to be updated with the group number for this overlay.
pIsOverlayInDataset	Pointer to a variable to be set to TRUE if the overlay data exists inside this dataset and set to FALSE if the if the overlay data is in another dataset.
uFlags	Reserved for future use. Pass 0.

Returns

0	The function was successful.
> 0	An error occurred. Refer to Return Codes.

Comments

This function will retrieve the attributes of an overlay and store their values in the structure pointed to by pOverlayAttributes.

pOverlayAttributes->uStructSize will be set to the value of the parameter uStructSize.

Most of the members of the structure pOverlayAttributes are based on the "Overlay Plane Module Attributes" in the DICOM standard.

If the overlay data is embedded in the "Image Pixel Data" (7FE0,0010), the flag OVERLAY_USEBITPLANE will be set inside pOverlayAttributes-> uFlags. If this flag is not set then the overlay data is stored in the "Overlay Data" (60xx,3000) element and in this case you can call LDicomDS::GetOverlayBitmap to get the data for that overlay.

pOverlayAttributes-> ptOrigin will hold the value of the "Overlay Origin" (60xx,0050) element, however the upper left pixel of the image will have the coordinate 0\0, instead of 1\1( as in the DICOM standard).

This function will always set pOverlayAttributes->crColor to black.

For multi-frame overlays, this function will update pOverlayAttributes->nNumFramesInOverlay with the value of "Number of Frames in Overlay" (60xx,0015) element and pOverlayAttributes-> uImageFrameOrigin with the value of "Image Frame Origin" (60xx,0051) element.

pOverlayAttributes-> szActivationLayer will be updated with the value of the element "Overlay Activation Layer" (60xx,1001)

Because DICOM uses "Repeating Groups" to represent multiple overlays, pGroupNumber is useful in knowing under which group number this overlay exists.

Required DLLs and Libraries

LTDIC

For a listing of the exact DLLs and Libraries needed, based on the toolkit version, refer to Files To Be Included With Your Application

Functions:	LDicomDS::GetOverlayCount, LDicomDS::GetOverlayActivationLayer, LDicomDS::GetOverlayBitmap, LDicomDS::GetOverlayBitmapList, LDicomDS::SetOverlayAttributes, LDicomDS::SetOverlayBitmap, LDicomDS::SetOverlayBitmapList, LDicomDS::DeleteOverlay
Topics:	Overlays Overview
	Overlays
	How to Disable the Automatic Loading of the default DICOM IOD Table