UNDERLAYDLGPARAMS

typedef struct _UNDERLAYDLGPARAMS
{
   L_UINT uStructSize;
   pBITMAPHANDLE pBitmap;
   L_BOOL bZoomToFit;
   L_UINT32 uUnderlayFlags;
   L_INT nUnderlayBitmapIndex;
   LPDLGBITMAPLIST pBitmapList;
   L_UINT32 uDlgFlags;
   LTCOMMDLGHELPCB pfnHelpCallback;
   L_VOID  *pHelpCallBackUserData;
} UNDERLAYDLGPARAMS,  * LPUNDERLAYDLGPARAMS;

The UNDERLAYDLGPARAMS structure provides information used to initialize the dialog box created by the LDialogImageEffect::DoModalUnderlay function. After the user closes the dialog box, this structure is updated with information about the user's selections.

Member	Description
uStructSize	Size of this structure, in bytes. Use the sizeof operator to calculate this value.
pBitmap	Ignored.
bZoomToFit	Flag that indicates the initial zoom level for previewing the image. Possible values are:
	Value	Meaning
	TRUE	Set the initial zoom level to "Zoom to fit".
	FALSE	Set the initial zoom level to "Normal (1:1)".

uUnderlayFlags	Flags that indicate how the underlying image is to be positioned. Possible values are:
	Value	Meaning
	UB_TILE	[0x00] Tile the underlay image. This repeats the underlying image, so that it fills the target image.
	UB_STRETCH	[0x01] Stretch the underlay image to fit the dimensions of the target image.

nUnderlayBitmapIndex	Index of the selected tile bitmap to use for underlay. This index points to an entry in pBitmapList member.
pBitmapList	Pointer to a DLGBITMAPLIST structure that references the images in the image picker. Set this to initialize the image picker in the dialog.
uDlgFlags	User interface flags for this dialog, which determines the layout and action of the dialog. Possible values are:
	Value	Meaning
	DLG_UNDERLAY_SHOW_CONTEXTHELP	[0x0002] dialog should contain a context sensitive help icon.
pfnHelpCallback	Ignored.
pHelpCallBackUserData	Ignored.