Tab Painting and Positioning

The tab pages provide a method for organizing the information in a notebook so that the user easily can see and navigate to that information. When a page is inserted with a major or minor tab attribute, the notebook displays a tab for that page, based on the orientation of the notebook. The contents of the tab can be painted either by the notebook control or the application.

If the notebook control is to paint the tabs, the application must associate a text string or bit map with the page whose tab is to be drawn. This is done by sending the BKM_SETTABTEXT or BKM_SETTABBITMAP message to the notebook control for the specified page. If neither of these messages is sent for an inserted page with a major or minor tab attribute, the application must draw the contents of the tab, through ownerdraw. The application receives a WM_DRAWITEM message whenever a tab page that has no text or bit map associated with it is to be drawn. The application can either draw the tab contents or return FALSE, in which case the notebook control fills the tab with the tab background color.

Positioning Tabs in Relation to the Top Tab:
There are seven page edges that define the back pages. The page attribute (BKA_MAJOR or BKA_MINOR) and the topmost page determine how the tabs are positioned. In most cases, the tabs must be drawn when their position changes. For example, this can happen when a page with a tab attribute is brought to the top of the notebook.

The new top major or minor tab will appear attached to the top page. The other tabs will appear as described in the following list. This information is provided to help you understand the relationship between the top tab and the other tabs so that you can organize the information you put into a notebook appropriately. The application has no control over tab positioning.

When the top page is a major tab page:
- Any major tabs prior to the top major tab are aligned on the last page of the notebook.
- Any major tabs after the top major tab are incrementally cascaded from the topmost edge to the last page.
- If the top major tab has minor tabs, no major tab is drawn on the page edge that immediately follows the top tab page. Instead, any major tabs that follow the top tab are incrementally cascaded, beginning on the second page, edge-down from the top tab. This is done to account for the minor tabs that are positioned between the top major tab and the major tab that follows it on the perpendicular notebook edge.
  The minor tabs are all positioned on the third page edge from the top, thereby giving the appearance of being between the top major tab and the next major tab.