Path: utzoo!utgpu!news-server.csri.toronto.edu!cs.utexas.edu!oakhill!nddsun1!soleil.sps.mot.com!cowan
From: cowan@soleil.sps.mot.com (Andrew H Cowan)
Newsgroups: comp.windows.x
Subject: Can "widgetClass" widget do graphics? Really?
Message-ID: <957@nddsun1.sps.mot.com>
Date: 28 Mar 91 18:21:50 GMT
Sender: root@nddsun1.sps.mot.com
Reply-To: cowan@soleil.sps.mot.com (Andrew H Cowan)
Organization: ASIC
Lines: 162

A while back I saw mention of a "poor man's graphics" widget that
was created by using the core widget "widgetClass".  I've tried 
using this to create a simple graphics window in which I can
draw stuff, but to no avail.

The following program creates a core widget "widgetClass" and a
pixmap.  I draw a rectangle into the pixmap then "XCopyPlane" the
pixmap to the widget.  Am I way off base?

I get the widget up, but no graphics appear.  

Please give me a clue.

        **                   /   \                   **
     ** **                  |     |                  **
     ** ** **                \___/                   ** **
     ********                                        ** **
      ******         __                  **          ****
        **        \_/oo\_/              ****         **
........**..........\||/................****.........**...........
Andy Cowan...........||.............cowan@soleil.sps.mot.com......

Define these resources:
	ClueMe*drawingarea.height: 300
	ClueMe*drawingarea.width: 600

Compile with (on a Sun4 or Solbourne): 
	cc -o ClueMe main.c -g -DXAW_BC -Dsun -DDEBUG -DX11R4 -I. -lXaw -lXmu -lXext -lXt -lX11

============ program start ===========

#include <stdio.h>
#include <X11/Intrinsic.h>
#include <X11/IntrinsicP.h>
#include <X11/StringDefs.h>
#include <X11/Xaw/Form.h>
#include <X11/Xaw/Label.h>
#include <X11/Xaw/Command.h>
#include <X11/Xaw/Box.h>
#include <X11/Xaw/Text.h>
#include <X11/Xaw/AsciiText.h>

Display *AppDisplay;
Widget Toplevel;     /* The Top of the widget hierarchy */
Widget drawingarea;  /* Global Core widget "widgetClass" drawing area widget */
Pixmap drawpixmap;   /* Pixmap for drawing graphics */
GC cleargc,drawgc;   /* GCs for clearing the pixmap, and drawing into the pixmap */

main(argc, argv)
int argc;
char *argv[];
{
   int i;
   Window win;
   XtAppContext ClueMeappcon;	

   Toplevel = XtAppInitialize( &ClueMeappcon, "ClueMe",
			       NULL, 0,
			       &argc, argv,
                               NULL, 
                               NULL, 0 );

   initdrawingarea( Toplevel );  /* inits drawingarea widget & drawgc GC */

   XtRealizeWidget( Toplevel );

   /* Draw a rectangle in the pixmap */
   XDrawRectangle( XtDisplay( drawingarea ),  
		   drawpixmap, 
		   drawgc, 
		   15,15, 10, 10 );

   updatescreen();                   /* Copy the pixmap to the screen */

   XtAppMainLoop(ClueMeappcon);

}

initdrawingarea( parent )
Widget parent;
{
   Arg widgetargs[15];
   XGCValues values;
   XtGCMask mask = GCForeground | GCBackground;
   char *fontname = "9x15";
   XFontStruct *fontinfo;

   int j,width;

   /* Core widget "widgetClass" to create drawing area */
   j=0;
   printf( "Creating drawing area.\n" );
   drawingarea = XtCreateManagedWidget( "drawingarea",
      widgetClass,
      parent,
      widgetargs, j );

   /* Offscren pixmap to draw stuff into.  Pixmap is then     */
   /* copied to the window so that you can see fucking thing. */

   if ( drawpixmap == NULL ){
      /* allocate pixmap, and allocate a GC to clear the pixmap */
      drawpixmap = XCreatePixmap( XtDisplay( drawingarea ),
			RootWindow( XtDisplay(drawingarea),DefaultScreen( XtDisplay( drawingarea ))),
			drawingarea->core.width,
			drawingarea->core.height,
			1 );
      values.foreground = 0;
      values.background = 0;
      cleargc = XCreateGC(XtDisplay(drawingarea),
			drawpixmap,
			mask, &values);
		
      /* Now clear out the pixmap */
      XFillRectangle( XtDisplay(drawingarea),
			drawpixmap,
			cleargc,
			0, 0,
			drawingarea->core.width,
			drawingarea->core.height );

      /* Now making a GC for use when drawing into the pixmap */
      fontinfo = XLoadQueryFont( XtDisplay(drawingarea), fontname);
      
      mask = GCForeground | GCBackground | GCDashOffset | GCDashList | GCLineStyle | GCFillStyle | GCFont;
      values.foreground = 1;
      values.background = 0;
      values.dashes = 1;
      values.dash_offset = 0;
      values.line_style = LineSolid;
      values.fill_style = FillSolid;
      values.font = fontinfo->fid;
      drawgc = XCreateGC( XtDisplay(drawingarea),
			  drawpixmap,
			  mask,
			  &values );

   }
}
updatescreen()
{
   GC copygc;
   XtGCMask mask_copygc = GCForeground | GCBackground;
   XGCValues values_copygc;

   values_copygc.background = drawingarea->core.background_pixel;
   values_copygc.foreground = 1;

   copygc = XtGetGC( drawingarea, mask_copygc, &values_copygc );

   if ( XtIsRealized( drawingarea )){ 
      printf( "Updating screen. %d x %d\n", drawingarea->core.width, drawingarea->core.height );
      /* Use XCopyArea on mono-chrome displays */
      XCopyPlane( XtDisplay( drawingarea ), 
		  drawpixmap, 
		  XtWindow(drawingarea), 
		  copygc, 
		  0,0, drawingarea->core.width, drawingarea->core.height,
	          0, 0, 1 );
   }

}