L_ContainerSetOffset

#include "LtCon.h"

L_LTCON_API L_INT L_ContainerSetOffset(pContainer, nXOffset, nYOffset, nZOffset)

Sets the container coordinates offset values.

Parameters

pCONTAINERHANDLE pContainer

Pointer to a container handle.

L_INT nXOffset

The X offset of the external representation.

L_INT nYOffset

The Y offset of the external representation.

L_INT nZOffset

The Z offset of the external representation.

Returns

Value Meaning
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 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 

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

Required DLLs and Libraries

See Also

Functions

Topics

Example

This will show to modify the container coordinates offset values to reflect the changes in the window offset.

L_INT ContainerSetOffsetExample(HWND             hWnd, 
                                                pCONTAINERHANDLE pContainer, 
                                                pBITMAPHANDLE    pBitmap, 
                                                LPRECT           prcView, 
                                                L_INT            cx, 
                                                L_INT            cy, 
                                                L_INT            nZoom, 
                                                L_INT*           pnHScroll, 
                                                L_INT*           pnVScroll) 
{ 
   L_INT nRet; 
   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 ) ; 
   nRet = L_ContainerSetOffset ( pContainer, - prcView->left, - prcView->top, 0 ) ; 
 
   return nRet; 
} 

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