Same here, but it does work when "Project=All Projects"

Ed

Apache error-log shows:

PHP Fatal error: Uncaught exception 'ezcGraphUnregularStepsException' with message 'Bar charts do not support axis with unregular steps sizes.' in /srv/www/htdocs/mantis/library/ezc/Graph/src/charts/line.php:250\nStack trace:\n#0 /srv/www/htdocs/mantis/library/ezc/Graph/src/charts/line.php(668): ezcGraphLineChart->renderData(Object(ezcGraphRenderer2d), Object(ezcGraphBoundings), Object(ezcGraphBoundings))\n#1 /srv/www/htdocs/mantis/library/ezc/Graph/src/charts/line.php(711): ezcGraphLineChart->renderElements(450, 405)\n#2 /srv/www/htdocs/mantis/plugins/MantisGraph/core/graph_api.php(139): ezcGraphLineChart->renderToOutput(450, 405)\n#3 /srv/www/htdocs/mantis/plugins/MantisGraph/pages/summary_graph_bycategory.php(42): graph_bar(Array, 'By Category', 450, 405)\n#4 /srv/www/htdocs/mantis/plugin.php(52): include('/srv/www/htdocs...')\n#5 {main}\n thrown in /srv/www/htdocs/mantis/library/ezc/Graph/src/charts/line.php on line 250, referer: http://-------/mantis/plugin.php?page=MantisGraph/summary_graph_imp_category.php

I had the same problem with my Mantis 1.2.1 installation and made some progress.

I found that on projects where there were more than about 10 reporters, developers or categories, any or all of summary_graph_bydeveloper.php, summary_graph_byreporter.php and summary_graph_bycategory.php will fail to render, showing a "broken image" icon. Right-clicking the "broken image" icon and opening it in a new tab reveals the 'ezcGraphUnregularStepsException' error.

This is a known constraint of the library.

Sources here: http://issues.ez.no/IssueView.php?Id=11168&activeItem=47
and here: http://ezcomponents.org/docs/tutorials/Graph (section titled "Lots of bars")

To solve this we need to manually set the label count on the X-axis.

I am currently trialing the following changes:

(a) graph_api.php in graph_bar():

$graph->xAxis->axisLabelRenderer = new ezcGraphAxisRotatedLabelRenderer();
$graph->xAxis->axisLabelRenderer->angle = 45;
<b>#--BEGIN ADDITION
$t_label_count = count( $graph->data[0] );
$graph->xAxis->labelCount = $t_label_count;
#--END ADDITION</b>

(b) graph_api.php in graph_group():

$graph->xAxis->axisLabelRenderer = new ezcGraphAxisRotatedLabelRenderer();
$graph->xAxis->axisLabelRenderer->angle = 45;
<b>#--BEGIN ADDITION
$t_label_count = 0;
foreach( array( 'open', 'resolved', 'closed' ) as $t_label ) {
    if( isset( $p_metrics[$t_label] ) && is_array( $p_metrics[$t_label] ) ) {
        $t_label_count = max( $t_label_count, count( $graph->data[$t_label] ) );
    }
}
$graph->xAxis->labelCount = $t_label_count;
#--END ADDITION</b>

These changes now set the label count correctly. However, graphs with many labels will now fail to render the "tiny fonts" needed.

This produces a new error such as:

Uncaught exception 'ezcGraphFontRenderingException' with message 'Could not fit string 'mystring' with font size '6' in box '33.13223192291 * 2.3902201054193'. Possible solutions to solve this problem: - Decrease the amount of steps on the axis. - Increase the size of the chart. - Decrease the minimum font size. - Use a font which consumes less space for each character.'

I found the easiest way to address this was to exclude the developers and reporters with low levels of activity.

summary_graph_bydeveloper.php:

<b>#--BEGIN ADDITION
$t_largest_count = 0;
foreach( array( 'open', 'resolved', 'closed' ) as $t_label ) {
    if( isset( $t_metrics[$t_label] ) && is_array( $t_metrics[$t_label] ) ) {
        foreach( $t_metrics[$t_label] as $t_developer => $t_count ) {
            $t_largest_count = max( $t_largest_count, $t_count );
        }
    }
}
$t_cutoff_count = $t_largest_count * 0.1;   # exclude bottom 10%  
foreach( $t_metrics['open'] as $t_developer => $t_count ) {
    if ( ( $t_metrics['open'][$t_developer] < $t_cutoff_count ) 
      and ( $t_metrics['resolved'][$t_developer] < $t_cutoff_count )
      and ( $t_metrics['closed'][$t_developer] < $t_cutoff_count ) ) {
        unset( $t_metrics['open'][$t_developer] );
        unset( $t_metrics['resolved'][$t_developer] );
        unset( $t_metrics['closed'][$t_developer] );
    }
}
#--END ADDITION</b>
graph_group( $t_metrics, lang_get( 'by_developer' ), $f_width, $f_width * $t_ar );

summary_graph_byreporter.php:

<b>#--BEGIN ADDITION
$t_largest_count = 0;
foreach( $t_metrics as $t_reporter => $t_count ) {
    $t_largest_count = max( $t_largest_count, $t_count );
}
$t_cutoff_count = $t_largest_count * 0.10;  # exclude bottom 10% 
foreach( $t_metrics as $t_reporter => $t_count ) {
    if ( $t_count < $t_cutoff_count ) {
        unset( $t_metrics[$t_reporter] );
    }
}
#--END ADDITION</b>
graph_bar( $t_metrics, lang_get( 'by_reporter' ), $f_width, $f_width * $t_ar );

In this way you can exclude the users that don't contribute much to the graph.

If this still doesn't help, you will then need to increase the graph width and size until you achieve a successful render.

For a more robust Mantis implementation, I would suggest letting these graphs have their own row and spread across all the columns, in other words have them ignore the "graphs per row" configuration. This gives them the extra width they need for their X-axis.

Note that changing from the bundled ezComponents library to a JpGraph installation gives better looking graphs and does not suffer from the same scalability issues.

Have commited the graph api for 1.3 - i need to think about the 'best' robust way to fix the actual graphs