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2.3.5 Working with Parts

   The following will guide you on how to works with parts.  To start, the 
   look of Document icons on the desktop look the same as today, even though 
   some of them, like the Text Part icon, represent OpenDoc documents. 
   Figure 15 shows some of the templates and document icons of the OpenDoc 
   parts. 


 


                                              



 
   Figure 15. OpenDoc Templates and OpenDoc Document Icons 

   From the user's point of view, there is no apparent distinction between an 
   OpenDoc document and a regular application document.  The menus are those 
   of the text part editor (because the root part, a text part, is active). 
   The menu names are those you would expect when editing text, except that 
   the File menu is named Document, and the Application System icon (top left 
   hand corner) is a document icon rather than an application icon.  Notice 
   the Templates folder (see Figure 15).  This contains the template icons 
   that the user drags to the document to create documents or parts. 

   An OpenDoc component can have the following different states: 

   °   Inactive but alive 
   °   Active 
   °   Selected 

   This state is indicated by the appearance (or absence) of a frame border. 

   An active part receives the focus for mouse and keyboard events.  It can 
   update the menu bar for example to add some part specific help and to 
   customize the edit menu items.  Only one part can have the focus at one 
   time.  The data of this part can then be changed or updated by the user. 

   Now suppose the user wants to edit the content of this document's embedded 
   graphics part.  The user would click inside the graphics part's frame. 
   The graphics part becomes active.  (A border appears around its frame, its 
   menus replace those of the text editor, and its tool palette appears.) 
   The text part is now inactive.  To select the circle, the user simply 
   clicks on the circle button on the tool palette.  As shown in Figure 16, a 
   number of things happen:  The graphics part editor highlights the selected 
   graphics object by displaying handles. 


 


                                              



 
   Figure 16. An Active OpenDoc Graphics Part 

   Note:  OpenDoc supports the in-out model of editing.  That means, you can 
   directly edit a nested object, although it may be embedded in another part 
   that is already embedded.  In OLE a part can only be activated in an 
   outside in order, which means to activate an embedded part the containing 
   part must be activated first. 

   Just as the content of a part may be activated for editing, an embedded 
   part (which is content of its containing part) may itself be selected for 
   certain operations.  To move or reseize a component, the component must be 
   selected.  To select an embedded component, the user drags across it or, 
   if the part is active, clicks its border.  The changed status is indicated 
   by a different pattern of the boarder.  Figure 17 shows what happens when 
   the user clicks the active frame border in Figure 16.  The graphics part 
   is selected and its border changes to show handles and the part that 
   contains it, the text part, becomes active again. It becomes active 
   because, if the graphic part is moved, the text flow of the containing 
   text part may have to change also.  The menus are replaced by the text 
   menus and the graphics palette goes away.  (The same thing happens to the 
   menus and palette when the user selects text in the text part or clicks 
   there to get an insertion point, and in all cases, content that resides in 
   the text part has been selected.) 


 


                                              

   Part 


 
   Figure 17. Resize a Selected Part 

   Parts viewed in frames can be active, inactive, or selected.  Parts viewed 
   as icons can be only inactive or selected.  The following describes the 
   three static (plural for status) of frames: 

   °   A part is active when it contains the current selection or the 
       insertion location (which could be a visible insertion point, as in 
       text, or an unmarked default location, as when the background in a 
       graphics part is clicked).  The selection may be within the part's 
       intrinsic content or it may be a part embedded in the active part. 
       When an embedded part becomes active, OpenDoc displays the active 
       frame border, a hashed line, around the part. 

   °   A part is inactive when the user is working in some other part.  When 
       viewed in a frame, an inactive part has no visible frame border around 
       it. 

       In OpenDoc several parts can be inactive but alive at the same time. 
       A clock showing the time and a moving ticker tape may update their 
       views concurrently. 

   °   A part is selected.  The user selects a part in a frame view by 
       dragging across it, or by clicking its border if it's the active part. 
       The containing part is responsible for the visual appearance of a 
       selected part's frame; typically, the frame shows handles, to allow 
       resizing.  To select a part viewed as an icon, the user simply clicks 
       the icon. 


   In general, as soon as the user clicks inside a part's frame, that part 
   becomes active.  The editor for the previously active part removes its 
   menus, palettes, and other user interface elements, and the new active 
   part's editor displays its user interface elements.  The active part 
   receives commands and keyboard events.  Only one part at a time may be 
   active within a document because, as in today's documents, there can be 
   only one selection at a time. 

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