Chart Design Overview

This page describes the basic steps and related subroutine calls for creating a simple chart.

Description:

Designing a chart can be as simple as calling two subroutines - one to initialize a new chart specification (.CHART INITIALIZE) and one to render the chart (.CHART RENDER). The following example illustrates the ILF statements needed to initialize and render a default pie chart (/tmp/piechart.png) using a previously defined dataset consisting of seven data values.

      *        Initialize Pie Chart
      PASS         PIE CHART                  FIELD            SHARE? N
      GOSUB    0CD .CHART INITIALIZE
      *        Note: We aren't showing the steps to supply the data, 
      *        see the next example
      *        Render chart
      SET      --- TEMP 256                   =      /tmp/piechart.png
      PASS     --- TEMP 256                   FIELD            SHARE? Y
      SUBR     0CD .CHART RENDER                    SUBPROCESS   END? N  FAIL 0

By adding a few additional subroutine calls to set a title, seven data values with sector labels, and a 3D view, a more useful chart can be rendered.

      *        ================================================================
      *        Create Pie Chart
      *        ================================================================
      *        Initialize a Pie Chart
      PASS         PIE CHART                  FIELD            SHARE? N
      GOSUB    0CD .CHART INITIALIZE
      *        Set a title
      PASS         Sales % By Day of Week     FIELD            SHARE? N
      GOSUB    0CD .CHART SET TITLE
      *        Set 3D view
      PASS         3D                         FIELD            SHARE? N
      GOSUB    0CD .PIE SET VIEW
      *        Add pie sectors with day of week labels and data values
      PASS         25                         FIELD            SHARE? N
      PASS         Monday                     FIELD            SHARE? N
      GOSUB    0CD .PIE SECT ADD NEXT
      PASS         14                         FIELD            SHARE? N
      PASS         Tuesday                    FIELD            SHARE? N
      GOSUB    0CD .PIE SECT ADD NEXT
      PASS         36                         FIELD            SHARE? N
      PASS         Wednesday                  FIELD            SHARE? N
      GOSUB    0CD .PIE SECT ADD NEXT
      PASS         2                          FIELD            SHARE? N
      PASS         Thursday                   FIELD            SHARE? N
      GOSUB    0CD .PIE SECT ADD NEXT
      PASS         12                         FIELD            SHARE? N
      PASS         Friday                     FIELD            SHARE? N
      GOSUB    0CD .PIE SECT ADD NEXT
      PASS         33                         FIELD            SHARE? N
      PASS         Saturday                   FIELD            SHARE? N
      GOSUB    0CD .PIE SECT ADD NEXT
      PASS         5                          FIELD            SHARE? N
      PASS         Sunday                     FIELD            SHARE? N
      GOSUB    0CD .PIE SECT ADD NEXT
      *        ================================================================
      *        Render chart
      *        ================================================================
      SET      --- TEMP 256                   =      /tmp/piechart.png
      PASS     --- TEMP 256                   FIELD            SHARE? Y
      SUBR     0CD .CHART RENDER                    SUBPROCESS   END? N  FAIL 0

Also notice the use of SUBR instead of GOSUB to call the chart rendering subroutine. This is a large process and compile times/sizes will be reduced if you call it as a separate process instead of including it in your process with a GOSUB.

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-- SteveFrizzell - 2010-04-01