LContainer::SetOffset

#include "Ltwrappr.h"

L_INT LContainer::SetOffset (nXOffset, nYOffset, nZOffset = 0)

L_INT nXOffset;	x-coordinates offset
L_INT nYOffset;	y-coordinates offset
L_INT nZOffset;	z-coordinates offset

Sets the container coordinates offset values.

Parameter	Description
nXOffset	The offset in the X direction of the external representation.
nYOffset	The offset in the Y direction of the external representation.
nZOffset	The offset in the Z direction of the external representation. Default value is 0.

Returns

SUCCESS	The function was successful.
< 1	An error occurred. Refer to Return Codes.

Comments

The user should set the offset every time the window that owns the container is scrolled.

When assigning an external representation to the container every point (Xa, Ya) in the an external representation is transformed by the container to the point (Xc, Yc) by using the following steps:

1.	Add offsets:

Xb = Xa + nXOffset

2.	Multiply by scalars:

Xc = (Xb * nXScalarNum) / nXScalarDen
Yc = (Yb * nYScalarNum) / nYScalarDen

Yb = Ya + nYOffset

The default offsets values are nXOffset = 0, nYOffset = 0 and nZOffset = 0.

Required DLLs and Libraries

LTCON

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

Example

This will show to modify the container coordinates offset values to reflect the changes in the window offset. The example assumes that there is an already initialized toolbar handle.

LContainer lCont ; 
/*static*/ L_VOID OnSize 
( 
HWND hWnd, 
pBITMAPHANDLE pBitmap, 
LPRECT prcView, 
L_INT cx, 
L_INT cy, 
L_INT nZoom, 
L_INT *pnHScroll, 
L_INT *pnVScroll 
) 
{ 
   SCROLLINFO si ; 
   L_INT      nXOffset, nYOffset ; 
   if ( NULL != pBitmap && pBitmap->Flags.Allocated ) 
   { 
      si.cbSize = sizeof ( SCROLLINFO ) ; 
      si.fMask  = SIF_ALL ; 
      // vertical scroll. 
      ::GetScrollInfo ( hWnd, SB_VERT, &si ) ; 
      si.nMin  = 0 ; 
      si.nMax  = BITMAPHEIGHT ( pBitmap ) ; 
      si.nPage = MulDiv ( cy, 100, nZoom ) ; 
      ::SetScrollInfo ( hWnd, SB_VERT, &si, TRUE ) ; 
      ::GetScrollInfo ( hWnd, SB_VERT, &si ) ; 
      *pnVScroll = si.nPos ; 
      // horizontal scroll 
      ::GetScrollInfo ( hWnd, SB_HORZ, &si ) ; 
      si.nMin  = 0 ; 
      si.nMax  = BITMAPWIDTH ( pBitmap ) ; 
      si.nPage = MulDiv ( cx, 100, nZoom ) ; 
      ::SetScrollInfo ( hWnd, SB_HORZ, &si, TRUE ) ; 
      ::GetScrollInfo ( hWnd, SB_HORZ, &si ) ; 
      *pnHScroll = si.nPos ; 
   } 
   else 
   { 
      si.cbSize = sizeof ( SCROLLINFO ) ; 
      si.fMask  = SIF_RANGE ; 
      si.nMin   = 0 ; 
      si.nMax   = 0 ; 
      ::SetScrollInfo ( hWnd, SB_VERT, &si, TRUE ) ; 
      ::SetScrollInfo ( hWnd, SB_HORZ, &si, TRUE ) ; 
      *pnHScroll = 0 ; 
      *pnVScroll = 0 ; 
   } 
   // set the painting rectangel. 
   SetRect ( prcView, 0, 0, BITMAPWIDTH ( pBitmap ), BITMAPHEIGHT ( pBitmap ) ) ; 
   if ( nZoom < 100 ) 
   { 
      nXOffset = MulDiv ( *pnHScroll, 100, nZoom ) ; 
      nYOffset = MulDiv ( *pnVScroll, 100, nZoom ) ; 
   } 
   else 
   { 
      nXOffset = *pnHScroll ; 
      nYOffset = *pnVScroll ; 
   } 
   OffsetRect ( prcView, - nXOffset, - nYOffset ) ; 
   prcView->left   = MulDiv ( prcView->left,   nZoom, 100 ) ; 
   prcView->top    = MulDiv ( prcView->top,    nZoom, 100 ) ; 
   prcView->right  = MulDiv ( prcView->right,  nZoom, 100 ) ; 
   prcView->bottom = MulDiv ( prcView->bottom, nZoom, 100 ) ; 
   lCont.SetOffset ( - prcView->top, 0 ) ; 
}

Help Version 19.0.2017.10.27

LEADTOOLS Container and Automation C++ Class Library Help

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Functions:	LContainer::SetScalar, LContainer::GetOffset
Topics:	Container Offsets