Bar charts are one of several linear data series charts
available in Visualforce. Linear series charts are charts plotted against a standard rectangular
grid.
Each data element in a linear series is described by an X,Y coordinate. The data series defines how to draw the
coordinate on the grid. The <apex:barSeries> charts draw bars stretching between an origin axis and the X,Y coordinates. The orientation attribute determines whether the origin axis is the left axis (Y)
or the bottom axis (X). Set <apex:barSeries
orientation="horizontal"> for bars that originate on the
left side of the chart, and <apex:barSeries
orientation="vertical"> for a column chart with bars that
rise from the bottom of the chart.
To plot multiple data points for each bar interval, group or stack
the bars within a single
<apex:barSeries> tag. Multiple
<apex:barSeries> tags in a single chart draw on top of each other, obscuring all
but the last data series. To create a vertical column chart, add all
fields to be grouped or stacked to the
yField attribute:
By
default, data fields in an
<apex:barSeries> are grouped on a chart. To stack them on top of each other, set
stacked="true".
Use the gutter attribute
to adjust spacing between grouped bars. Use the groupGutter attribute to adjust spacing
between groups. Use the xPadding and yPadding attributes
to adjust the spacing between the chart axes and the bars themselves.
By default, legend titles for stacked or grouped bar charts use
the names of fields in the
yField attribute. In the previous example, the default titles are “data1”,
“data2”, and “data3”. To give the legend
more meaningful titles, use the
title attribute of the
<apex:barSeries> component. Use commas to separate items. For example,
title="MacDonald,Promas,Worle":