Coder's Clinic 2:  Let's Print! 


      ******************************  
      * First of all let me state  *
      * that last months code was  *
      * mangled in the proccess of *
      * translating it to HTML     * 
      * (for WWW) and AmigaGuide,  *
      * if anyone would like the   *
      * c.source just email me     *
      * TOPIC:need CC1.c           *
      ******************************  
        
        This month, as promised, we will add text to our "AmigaHelloWorld"
 program.  Programming the Amiga, can be as much fun as playing a game on 
 your Amiga, if you have the right attitude.  So if you have the tute, 
 I'm the tutor...

        Printing text to the window is very simple and you have two ways
 of going about it.

      *****--------------------------------------------------       
      * N *   I STRONGLY SUGGEST INVESTING IN THE COMPLETE  |
      * O *   SET OF AMIGA ROM KERNEL MANUALS... AT THE     |
      * T *   VERY LEAST YOU SHOULD TRY TO GET THE LIBRARIES|       
      * E *   MANUAL ...THERE ARE MANY EXAMPLES/EXPLANATIONS|       
      *****--------------------------------------------------
        

 ==========================================================================

 FIRST WAY: INTUITEXT STRUCTURE
           To render text using Intuition, you must fill an IntuiText
           structure:
           
           struct IntuiText
           {
                UBYTE FrontPen, BackPen;
                UBYTE DrawMode;
                WORD  LeftEdge;
                WORD  TopEdge;
                struct TextAttr *ITextFont;
                UBYTE *IText;
                struct IntuiText *NextText;
           };     

        After filling the structure  you would call the PrintIText()
        function....
        
        *proto* 
        void PrintIText(struct RastPort *rp, 
                        struct IntuiText *iText,
                        long left, long top);
        
        I won't use this method for our simple program, but we will in the
 future.
        

 ==========================================================================

                          SECOND WAY: THE TEXT FUNCTION
                          
            The Text() function is in the graphics.library and is the
 method that we will use in our example program.  Since the funtion resides
 in the graphics.library we must open it.
            
       *proto*
       void Text(struct RastPort *rp,
                 STRPTR mystring, ULONG count);
                 
       ex.   C CODE
             .
             .
             .
             Text(rp,"Hello World",11);
             .
             .
             .
             END OF CODE
             
       In our example we simply called Text() passed a pointer to our
 RastPort, passed the string to print, and the number of characters
 in the string. Simple?
       
 ========================================================================

        
        With this knowledge, lets build on to our "AmigaHelloWorld" code. 


      *****-------------------------  *****-------------------------       
      * N *   ALL CODE IS INTENDED |  * N *   I COMPILED THIS CODE |
      * O *   FOR VERSION 2.0 OR   |  * O *   WITH SAS/C V6.0 AND  |
      * T *   ABOVE...             |  * T *   HAD NO ERRORS OR     |       
      * E *                        |  * E *   WARNINGS             |       
      *****-------------------------  *****-------------------------

//.C..C.O.D.E..............................................................


 #include <exec/types.h>                 /* THE INCLUDE FILES WE NEED */
 #include <intuition/intuition.h>
 #include <intuition/intuitionbase.h>
 #include <graphics/gfxmacros.h>
 #include <intuition/screens.h>
 #include <clib/exec_protos.h>
 #include <clib/dos_protos.h>
 #include <clib/graphics_protos.h>
 #include <clib/intuition_protos.h>

 #define INTUI_V36_NAMES_ONLY

 void handle_window_events(struct Window *window); /* FUNCTION PROTOTYPE */

 struct Library *IntuitionBase , *GfxBase = NULL;

 VOID main (int argc, char *argv[])
 {
 struct Window *window;
        
        /**************************************************************** 
        * Open the intuition.library so that we can access its funtions *
        * in our program                                                * 
        ****************************************************************/
        
        IntuitionBase = OpenLibrary ( "intuition.library",37); 
        if (IntuitionBase != NULL) /* did intuition.library open ? */
        { 
        
                GfxBase = OpenLibrary ( "graphics.library",37); 
                if (GfxBase != NULL) /* did graphics.library open ? */
                {
        /* YES it opened ! */
                         
                window = OpenWindowTags(NULL,
                            WA_Left,      20,
                            WA_Top,       20,
                            WA_Width,     400,
                            WA_Height,    80,
                            WA_CloseGadget,  TRUE,
                            WA_DragBar, TRUE,
                            WA_IDCMP,  IDCMP_CLOSEWINDOW,
                            WA_Title,  "Hello Amiga World",
                            TAG_DONE);
   
                if(window == NULL) /* Window filled? */
                {
                        /* NO, Window Failure */
                }
                else
                {
                        /* YES, do somthing */
                        /* LIKE PRINT SOME TEXT !!!!)*/
                        SetAPen(window->RPort,1);
                        Move(window->RPort,30,30);
                        Text(window->RPort,"Hello World",11);
                        handle_window_events(window);
                        CloseWindow(window); /* Need an explanation? */ 
                }
           CloseLibrary((struct Library *)GfxBase);
           }
                
        /* AllWays close the Libraries we opened */
        CloseLibrary((struct Library *)IntuitionBase);
        }
 }
 /******************************************************************* 
 This event loop is very simple they can get complex, but for our   *
 purpose this works fine....    (I will explain this soon)          *
 *******************************************************************/
 void handle_window_events(struct Window *window)
 {
        WaitPort(window->UserPort);
 }   


  

// END OF CODE -----------------------------------------------------------

That should do it ... a nice window with a nice greeting :)



                  NEXT MONTH: ADD A GADGET TO OUR WINDOW!!

        The gadget is the greatest invention known to man...at least in my
 book.
        
        Please let me know what you think of this column...I had one
 response to last month's article... one person in the whole world read the
 column???
        


                                       David Loeser   
                                    Synthesis Software