L_DicomGetOverlayAttributes

#include "ltdic.h"

L_LTDIC_API L_UINT16 L_DicomGetOverlayAttributes(hDS, uOverlayIndex, pOverlayAttributes, uStructSize, pGroupNumber, pIsOverlayInDataset, uFlags)

HDICOMDS hDS;	/* a DICOM handle */
L_UINT uOverlayIndex;	/* the overlay index */
pOVERLAYATTRIBUTES pOverlayAttributes;	/* pointer to the overlay attributes structure to be updated */
L_UINT uStructSize;	/* the size of the OVERLAYATTRIBUTES structure - pass sizeof(OVERLAYATTRIBUTES) */
L_INT * pGroupNumber;	/* variable which will be updated with the group number for this overlay */
L_BOOL * pIsOverlayInDataset;	/* variable which will be set to TRUE if the overlay exists inside this dataset and set to FALSE otherwise*/
L_UINT uFlags;	/* reserved for future use */

Retrieves the attributes of the overlay at the specified index.

Parameter	Description
hDS	A DICOM handle.
uOverlayIndex	The index of the overlay for which to get the attributes. This index is zero-based.
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 updated with TRUE if the overlay data exists inside this dataset and updated with 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 L_DicomGetOverlayBitmap 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

Platforms

Win32, x64

Functions:	L_DicomGetOverlayCount, L_DicomGetOverlayActivationLayer, L_DicomGetOverlayBitmap, L_DicomGetOverlayBitmapList, L_DicomSetOverlayAttributes, L_DicomSetOverlayBitmap, L_DicomSetOverlayBitmapList, L_DicomDeleteOverlay
Topics:	Overlays Overview
	Overlays