LEADTOOLS provides functions for drawing pages, with or without zones. The zones may or may not be selected. Before drawing a page, with or without its zones, that page must be set as "active."
Before drawing a page (with or without its zones), set the page as "active" by calling L_Doc2SetActivePage/l_doc2setactivepageext. After the active page has been set, draw the page by calling L_Doc2DrawPage/l_doc2drawpageext. This function gives you the option of drawing the page with or without the zones.
To draw a page "zoomed in", set the paint zoom factor before actually drawing the page. To set the paint zoom factor for a specific page, call L_Doc2SetPaintZoomFactor/l_doc2setpaintzoomfactorext. Get the current paint zoom factor for a specific page by calling L_Doc2GetPaintZoomFactor/l_doc2getpaintzoomfactorext.
Select and draw a zone in the HDC by calling L_Doc2SelectZone/L_Doc2SelectZoneExt or L_Doc2SelectZoneByPoint/l_doc2selectzonebypointext. L_Doc2SelectZone selects or deselects a zone by specifying a page index and a zone index. Set the pen to draw zones by calling L_Doc2SetZonePen. If the zone is selected, the zone is drawn with a "selection rectangle" around it. Set the pen used to draw the selected zone using L_Doc2SetSelectedZonePen.
The L_Doc2SelectZoneByPoint/l_doc2selectzonebypointext selects a zone by determining which zone on the page contains the specified point. If a zone containing that point is found, that zone is selected and the zone is redrawn with a "selection rectangle" around it. As with the L_Doc2SelectZone/L_Doc2SelectZoneExt function, the pen used to draw the zones is set using the L_Doc2SetZonePen. The pen used to draw the selected zone is set using L_Doc2SetSelectedZonePen.
When scrolling a page that contains zones, the zones must also be scrolled in order to display the zones at the proper location on the page. The L_Doc2OffsetZones function takes the amount the page was scrolled and scrolls the zones accordingly.
For more information refer to: