Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!uwm.edu!cs.utexas.edu!tut.cis.ohio-state.edu!ucbvax!bloom-beacon!athena.mit.edu!jstravis
From: jstravis@athena.mit.edu (John S. Travis)
Newsgroups: comp.windows.x
Subject: XDrawLine
Message-ID: <1989Dec2.193728.2991@athena.mit.edu>
Date: 2 Dec 89 19:37:28 GMT
Sender: root@athena.mit.edu (Wizard A. Root)
Reply-To: jstravis@athena.mit.edu (John S. Travis)
Distribution: usa
Organization: Massachusetts Institute of Technology
Lines: 120

Can anyone help me with what must be an obvious(to others) error
I am merely trying to read in some data ponts and draw lines
connecting them. The window pops up, but nothing is drawn, not even
the XDrawLines i threw in randomly throughout the program. What's the deal?
Thanks for any help!

john travis
jstravis@athena.mit.edu

---------------------------------------------------
#include <X11/Intrinsic.h>
#include <X11/StringDefs.h>
#include <Xw/Xw.h>
#include <Xw/WorkSpace.h>
#include <stdio.h>

#define MAXPOINTS 100
#define MAXLINES 100

void get_data();
void draw_data();

typedef struct {
  int line_num;
  int num_line_points;
  double points[MAXPOINTS];
} data_struct;

int TOTAL_LINES;

main(argc,argv)
     int    argc;
     char   *argv[];
{
  Widget  toplevel,canvas;
  GC gc;
  XGCValues values;
  Arg wargs[2];
  data_struct data[MAXLINES];

  toplevel = XtInitialize(argv[0],"Stream",NULL,0,&argc,argv);

  canvas = XtCreateManagedWidget("canvas",XwworkSpaceWidgetClass,toplevel,NULL,0);

  XtRealizeWidget(toplevel);

/* get the colors user has set for the widget */
  XtSetArg(wargs[0],XtNforeground, &values.foreground);
  XtSetArg(wargs[1],XtNbackground, &values.background);
  XtGetValues(canvas,wargs,2);
  values.line_width =4;
  gc = XtGetGC(canvas,GCForeground | GCLineWidth | GCBackground, &values);

  XDrawLine(XtDisplay(canvas), XtWindow(canvas),gc, 24,89,30,133);

  get_data(data);
  draw_data(data,XtDisplay(canvas),XtWindow(canvas),gc);
  
  XtMainLoop();
}

void get_data(data)
     data_struct  data[];   /* 100 streamlines is the max! */
{
  FILE *fin;
  int i,j,num_line_points;

  fin = fopen("str.dat","r");
  if (fin == NULL){
    printf("Unable to open %s\n","str.dat");
    exit(1);
  }

  i=0;
  printf("entering while\n");
  while (fscanf(fin,"%d", &num_line_points) != EOF)
    {
      data[i].line_num = i;
      printf("line %d", data[i].line_num);

      data[i].num_line_points = num_line_points;
      printf(" has %d points\n",data[i].num_line_points);

      for (j=0; j < (2*num_line_points); j++){
        fscanf(fin,"%lf",&data[i].points[j]);
        printf("%lf ",data[i].points[j]);
      }
      printf("\n");   i++;

    }
  TOTAL_LINES = i;
  printf("out of while\n");
}



void draw_data(data,dpy,win,gc)
     data_struct data[];
     Display *dpy;
     Window win;
     GC gc;
{
  int j,i;

  printf("lines are %d\n",TOTAL_LINES);
  printf("first two point are %lf , %lf and  %lf , %lf \n",data[0].points[0],
             data[0].points[1],data[0].points[2],data[0].points[3]);

  XDrawLine(dpy,win,gc,20,35,45,70);
  for (i=0; i<(TOTAL_LINES-1); i++)
    {
      XDrawLine(dpy,win,gc,data[i].points[0],data[i].points[1],
                data[i].points[2],data[i].points[3]);

      for(j=2; j < (data[i].num_line_points - 1); j++)
        XDrawLine(dpy,win,gc,data[i].points[j],data[i].points[j+1],
                  data[i].points[j+2], data[i].points[j+3]);

    }
}