Topic       : TOS - The Operating System
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View Ref-File13.8.29.9  CBDraw                                                  TOS

C notation:

        void cdecl (*CBDraw) (ObjectInfo *objectinfo,
                              int outScreen,
                              int outHandle,
                              int outDevID,
                              GRECT *Size,
                              GRECT *Clip);

PurePascal notation:
(d1..d5 are dummy values, here NULL or 0 shoul be passed)

        CBDraw: procedure(d1,d2: pointer; d3,d4,d5: longint;
                          objectinfo: POLGAObjectInfo;
                          outScreen,
                          outHandle,
                          outDevID: integer;
                          Size,
                          Clip: GRECTPtr);

If CBDraw is called by the Client, the Server should check whether the 
file OLGAObjectInfo.Filename (the OLGAObjectInfo pointer is passed by 
CBDraw) is already loaded - if not then it should do so now. Since the 
loading should actually have been ensured through OLGA_EMBED, one can 
in that case alternatively signal an error, for example by crossing 
out the object area using two red lines (or possibly by displaying the 
actual error as plain text in the object area).

Then the Server can draw the graphics with the help of the passed 
values (see below). Inside of this drawing routine the Server must not 
make any wind_update calls! The CBDraw parameters have the following 
meaning:

   . outScreen signals whether output is to be to the screen (<>0) or 
     not (=0). An on-screen preview is screen output too!

   . outHandle is the handle of the open workstation (screen, printer 
     etc.), to which the Server can output directly. If outScreen is 
     <>0, the Server can also alternatively output to its own screen 
     workstation.

   . outDevID gives the device number (from ASSIGN.SYS) of the driver 
     to output to. If outputting purely to screen this field contains 
     NULL. Although a preview is an output to the screen, outDevID in 
     that case specifies, for instance, the driver to which output 
     will be made later during printing. In that case the Server can 
     try to open that driver in order to better match the screen 
     output to subsequent printer output.

   . Size is the rectangle in which the passed graphic must fit 
     exactly, even if this leads to distortions. Clip is the Clipping 
     rectangle (set before the call).

Important: A Server must not make any AES calls during CBDraw! (Unless 
the AESPB pointer field has been adapted by the ClientGEMPB; 
nevertheless wind_update remains taboo for ID4-Servers). Additionally 
the colour palette in Callback must not be changed.

This function was added to OLGA in Rev 1.2 (1996-11-20).

See also: OLGA protocol   OLGA_EMBEDDED   OLGA_UNEMBED 
OLGA_INPLACEUPDATE   CBUnembed