ImageGear for C and C++ on Windows v19.10 - Updated
IG_dspl_scroll_handle
API Reference Guide > Core Component API Reference > Core Component Functions Reference > Display Functions > IG_dspl_scroll_handle

This function is designed to handle scrollbar messages from an hWnd window.

Declaration:

 
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AT_ERRCOUNT   ACCUAPI  IG_dspl_scroll_handle( 
        [IN] HIGEAR hIGear, 
        [IN] DWORD dwGrpID,
        [IN] HWND hWnd, 
        [IN] AT_MODE nScrlType,
        [IN] AT_MODE nScrlMode,
        [IN] LONG lScrlValue,
        [OUT] LPAT_SCROLL_INFO lpScrollInfo
);

Arguments:

Name Type Description
hIGear HIGEAR ImageGear handle of image.
dwGrpID DWORD Identifier of group that will be used to perform operation.
hWnd HWND Handle of window where image is displayed and where scrolling is performed.
nScrlType AT_MODE

Scroll command. Its value is platform dependent.

For Win32 platforms there should be LOWORD(wParam) and for Win16, wParam. Valid values are:

  • IG_DSPL_SCROLL_HORIZONTAL
  • IG_DSPL_SCROLL_VERTICAL
nScrlMode AT_MODE

Scroll command. Its value is platform dependent.

For Win32 platforms there should be LOWORD(wParam) and for Win16, wParam. Valid values are:

  • IG_DSPL_HSCROLLBAR
  • IG_DSPL_HSCROLLBAR_AUTO
  • IG_DSPL_HSCROLLBAR_ENABLE
  • IG_DSPL_HSCROLLBAR_DISABLE
  • IG_DSPL_VSCROLLBAR
  • IG_DSPL_VSCROLLBAR_AUTO
  • IG_DSPL_VSCROLLBAR_ENABLE
  • IG_DSPL_VSCROLLBAR_DISABLE
nScrlValue LONG Scroll value. It is also platform dependent and its value may have a different meaning from nScrlType. Under the Windows platform, it is not used because the scroll position is obtained directly from the scrollbars.
lpScrollInfo LPAT_SCROLL_INFO Receive updated scroll parameters (not scrollbar). If NULL then it is ignored.

Return Value:

Returns the number of ImageGear errors that occurred during this function call.

Supported Raster Image Formats:

All pixel formats supported by ImageGear for C and C++.

Sample:

ASCII, Display, Image Util, Magnify, Medical, MFC, Panning, ArtX, Vector, Filters, Flashpix

Example:

 
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HIGEAR           hIGear;       /* HIGEAR handle of image      */ 
DWORD           nGrpID;       /* display group identifier     */
 ...
case WM_HSCROLL:           /* horizontal scrolling   */
IG_dspl_scroll_handle( hIGear, nGrpID, hWnd, IG_DSPL_SCROLL_HORIZONTAL, LOWORD(wParam),
HIWORD(wParam), NULL );
        break;
case WM_VSCROLL: /* vertical scrolling */
IG_dspl_scroll_handle( hIGear, nGrpID, hWnd, IG_DSPL_SCROLL_VERTICAL, LOWORD(wParam),
HIWORD(wParam), NULL );
        break;
 ...

Remarks:

This function should not be used to set the absolute scroll position; function IG_dspl_scroll_to() should be used instead.