Description: ------------ When you have datasets with only one value no bar will show upp. I know it's kind of silly to have a graph with only one bar... but it's not my call. I've been trying to fix it and think I've come up with a solution. By changing the lines 705-707 in Axis.php from: if ($this->_axisValueSpan == 0) { $this->_delta = false; } elseif ($this->_type == IMAGE_GRAPH_AXIS_X) { to: /* if ($this->_axisValueSpan == 0) { $this->_delta = false; } elseif ($this->_type == IMAGE_GRAPH_AXIS_X) { */ if ($this->_type == IMAGE_GRAPH_AXIS_X) { In other words, by removing the first if-satement. Test script: --------------- <?php require_once 'Image/Graph.php'; // Create the graph $Graph =& Image_Graph::factory('graph', array(400, 300)); // Add a TrueType font $Font =& $Graph->addNew('font', 'Verdana'); // Set the font size to 11 pixels $Font->setSize(8); $Graph->setFont($Font); $Graph->add( Image_Graph::vertical( Image_Graph::factory('title', array('Bar Chart Sample', 12)), Image_Graph::vertical( $Plotarea = Image_Graph::factory('plotarea'), $Legend = Image_Graph::factory('legend'), 90 ), 5 ) ); $Legend->setPlotarea($Plotarea); // Create the dataset $Dataset =& Image_Graph::factory('random', array(1, 2, 15, false)); // Create the 1st plot as smoothed area chart using the 1st dataset $Plot =& $Plotarea->addNew('bar', array(&$Dataset)); // Set a line color $Plot->setLineColor('gray'); // Set a standard fill style $Plot->setFillColor('blue@0.2'); // Output the Graph $Graph->done(); ?> Expected result: ---------------- A graph with one centered bar. Actual result: -------------- A graph with no bar at all.

I want to provide my testing result for generating a graph with only one bar in it for v0.7.2. If the x-axis is a Image_Graph_Axis_Category or Image_Graph_Axis, the bar does get plotted. However, the bar is plotted right on the y-axis. If you change the color of the bar graph you will be able to view this. For a logarithmic axis, the single bar is generated correctly. There are existing work arounds for this behavior. If the x-axis is linear, Image_Graph_Axis, then force a minimum and maximum x-axis value and the bar will display nicely. If the x-axis is a category type, Image_Graph_Axis_Category, then add additional value to the dataset with x and y value (y's set to zero) in the desired order to have it appear on the x-axis. A possible appropriate behavior is to modify the code to let users input an offset value from the y-axis for the first value on the x-axis or vice versa, something like, setAxisOffset. This would also be beneficial for logarithmic axis as well. Alex

hello, i have the same problem - a bar chart and only one value. i've read alexs post, but i just don't get it. i want the one bar i have to be displyed and using the whole width of the "chartboard"/plotarea. somebody can please post a sample code? thank you very much!

I just wanted to confirm that christoffer's solution worked for me - my single data point graphs now plot properly as expected. Thanks!

For one graph, this fix resolved the problem. But for another graph, this fix caused the error "Division by zero in /usr/share/php/Image/Graph/Axis.php." So I changed the code from: function _calcDelta() { if ($this->_axisValueSpan == 0) { $this->_delta = false; } elseif ($this->_type == IMAGE_GRAPH_AXIS_X) { $this->_delta = (($this->_transpose ? $this->height() : $this->width()) - ($this->_axisPadding['low'] + $this->_axisPadding['high'])) / ($this->_axisValueSpan + ($this->_pushValues ? 1 : 0)); } else { $this->_delta = (($this->_transpose ? $this->width() : $this->height()) - ($this->_axisPadding['low'] + $this->_axisPadding['high'])) / ($this->_axisValueSpan + ($this->_pushValues ? 1 : 0)); } } to: function _calcDelta() { $div = $this->_axisValueSpan + ($this->_pushValues ? 1 : 0); $div = $div ? $div : 1; if ($this->_type == IMAGE_GRAPH_AXIS_X) { $this->_delta = (($this->_transpose ? $this->height() : $this->width()) - ($this->_axisPadding['low'] + $this->_axisPadding['high'])) / $div; } else { $this->_delta = (($this->_transpose ? $this->width() : $this->height()) - ($this->_axisPadding['low'] + $this->_axisPadding['high'])) / $div; } } I don't know what does _pushValues mean, but in my application, this code works well.