BUG: PG Chart Displays May Have Uneven Spacing Between Bars

MS-DOS                 | WINDOWS

The information in this article applies to:

• The C Run-time (CRT), included with:

      - Microsoft C for MS-DOS, versions 6.0, 6.0a, and 6.0ax
      - Microsoft C/C++ for MS-DOS, version 7.0
      - Microsoft Visual C++ for Windows, version 1.0
  

SYMPTOMS

If a large number of bars or pie slices are displayed in a Presentation Graphics chart, the spacing between the bars or pie slices may be inconsistent. In most situations, any variation between the sizes of bar separations is minimal and generally unnoticeable. The sample program below demonstrates this problem on a bar, column, and pie chart.

STATUS

Microsoft has confirmed this to be a problem in C versions 6.0, 6.0a, 6.0ax, 7.0, and Visual C++ version 1.0. We are researching this problem and will post new information here as it becomes available.

In general, this problem really has to do with the resolution of the video system. As the bars or pie wedges get closer together the differences of width become more apparent. Since the widths are based on an average, eventually a difference of one or two pixels becomes noticable.

MORE INFORMATION

Sample Code

#include <conio.h>
#include <stdlib.h>
#include <graph.h>
#include <string.h>
#include <pgchart.h>

#define COUNTRIES 25

                                21.3F, 42.5F, 14.3F, 35.2F, 21.3F,
                                42.5F, 14.3F, 35.2F, 21.3F, 32.6F,
                                42.5F, 14.3F, 35.2F, 21.3F, 32.6F,
                                42.5F, 14.3F, 35.2F, 21.3F, 32.6F };
char _far *category[COUNTRIES] = { "AB","YZ","UR","GD","USA","UK",
                                   "UR","GD","USA","UK","UR","GD",
                                   "USA","UK","Other","UR","GD",
                                   "USA","UK","Other","UR","GD",
                                   "USA","UK","Other" };

                                  1, 0, 1, 0, 0, 1, 0, 1, 0, 1, 1,
                                  1, 1, 1 };

void main(void)

   chartenv env;

   if( !_setvideomode( _MAXRESMODE ) )
           exit( 1 );

   _pg_initchart();              // Initialize chart system

   // Single-series bar chart

   _pg_defaultchart( &env, _PG_BARCHART, _PG_PLAINBARS );
   strcpy( env.maintitle.title, "Widget Production" );
   _pg_chart( &env, category, value, COUNTRIES );
   getch();
   _clearscreen( _GCLEARSCREEN );

   // Single-series column chart

   _pg_defaultchart( &env, _PG_COLUMNCHART, _PG_PLAINBARS );
   strcpy( env.maintitle.title, "Widget Production" );
   _pg_chart( &env, category, value, COUNTRIES );
   getch();
   _clearscreen( _GCLEARSCREEN );

   // Pie chart

   _pg_defaultchart( &env, _PG_PIECHART, _PG_PERCENT );
   strcpy( env.maintitle.title, "Widget Production" );
   _pg_chartpie( &env, category, value, explode, COUNTRIES );
   getch();

   _setvideomode( _DEFAULTMODE );