The setColumnSpacing( spacing ) function allows you to specify how much space there is between each column. The function has the same effect for a graph with a single series or with multiple series.

A spacing value of 0 means no spacing.

A spacing value of 100 means the spacing within each column either side of the bar(s) will be the same width as each bar.

Bars next to each other
setColumnSpacing( 0 )

Some spacing
setColumnSpacing( 50 )

More spacing
setColumnSpacing( 100 )

Series spacing

When there are multiple series you can control how they are positioned inside each column using the setStackedBarSpacing( spacing ) and setStackedBarOverlap( overlap ) functions.

Spacing
setStackedBarSpacing( 50 )
or setStackedBarOverlap( -50 )

No Spacing
setStackedBarSpacing( 0 )
or setStackedBarOverlap( 0 )

Overlap
setStackedBarSpacing( -50 )
or setStackedBarOverlap( 50 )

Displaying values

The setValueStyle function allows you to display values above or inside of the bars:

<?php
  include( 'chartlogix.inc.php' );

  $chart = new BarChart();

  $chart->setLegendWidth( 0 );

  $chart->setColumnSpacing( 50 );

  $chart->doBarSeries( 'MP3 Player Sales', 'FFCC00' );
  $chart->addData( 'Jan', 191 );
  $chart->addData( 'Feb', 217 );
  $chart->addData( 'Mar', 178 );
  $chart->addData( 'Apr', 263 );
  $chart->addData( 'May', 321 );

  $chart->setValueStyle( 'arial.ttf', 17, '000000', 1, 90 );

  $chart->drawPNG( 500, 400 );

The values can be placed above the bars, or at various positions inside the bars, and can be rotated as necessary. The above example uses a position of 1 and an angle of 90 to place the values vertically above the bars. See the function reference for more details.

Next Steps

The Customizing Axes Tutorial tells you about controlling and positioning the axes.

The Function Reference Page gives you a complete list of functions which you can use to customise the deisgn of the bar graph.

The Bar Graph Designer allows you to interactively customise a bar graph and see the PHP code.

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