The main steps you need to carry out to create a chart are as follows:
Create a Chart
object, typically setting the chart type using the type
property, and as appropriate setting labels for the chart title,
axis labels, etc.
Create one or
more Series objects, as children of the Chart object, and use these
to specify the data which the chart will display. You can specify
the data in various ways, typically using the values
property, or the xvalues
and yvalues properties
separately.
Optionally,
customize the chart's appearance by setting various properties
of the Chart object. You can also set various properties of the
child Series objects (for example, to set the colors used to display
each series).
The Chart object responds dynamically to each change you make. (You can
switch this off using the update
property). So, having created a chart, you can for example convert a
line chart to an area chart by changing the type
property.
Here
is an example of a function which produces a simple chart showing two
different series:
’Chart_Microsoft;MS;data;years;revenue;income;ŒIO [1] © Sample line chart [2] MS„'Œ' ŒNEW 'Window' ª MS.title„'Sample chart' [3] MS.Chart.New 'Chart' ª MS.Chart.align„¯1 ª MS.Chart.type„'line' [4] MS.Chart.title„'Microsoft Financials FY 1985-2004' [5] MS.Chart.yaxislabel„'$ Millions' [6] © [7] MS.Chart.s1.New 'series' ª MS.Chart.s1.caption„'Revenue' [8] MS.Chart.s2.New 'series' ª MS.Chart.s2.caption„'Net Income' [9] © [10] © Set up data [11] ŒIO„0 [12] years„1985+¼20 [13] revenue„140 198 346 591 805 1186 1847 2777 3786 4714 6075 [14] revenue„revenue,9050 11936 15262 19747 22956 25296 28365 32187 36835 [15] income„24 39 72 124 171 279 463 708 953 1146 1453 [16] income„income,2195 3454 4490 7785 9421 7346 5355 7531 8168 [17] © [18] MS.Chart.s1.yvalues„revenue ª MS.Chart.s1.xvalues„years [19] MS.Chart.s2.yvalues„income ª MS.Chart.s2.xvalues„years ’
This
produces a window which contains the following chart:
(Note
that the number of ticks and labels shown may vary as the window is
resized).
We
can now customize the Chart object in various ways. For example, we
can use the style property
to display a grid, the subtitle
property to add a subtitle, and the note
property to add a note:
MS.Chart.subtitle„'(since IPO)' MS.Chart.note„'Source: Microsoft Inc' MS.Chart.style„(1+8)
The graph will now look like this:
We can also set attributes of the individual series. For example, we
might want the 'Net Income' line to be displayed as a
dotted line, in green:
MS.Chart.s2.linetype„2 MS.Chart.s2.color„0 180 0