1 files changed, 88 insertions, 0 deletions
diff --git a/library/Icinga/Chart/Graph/StackedGraph.php b/library/Icinga/Chart/Graph/StackedGraph.php
new file mode 100644
index 0000000..49801a9
--- /dev/null
+++ b/library/Icinga/Chart/Graph/StackedGraph.php
@@ -0,0 +1,88 @@
+<?php
+/* Icinga Web 2 | (c) 2013 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Chart\Graph;
+
+use DOMElement;
+use Icinga\Chart\Primitive\Drawable;
+use Icinga\Chart\Render\RenderContext;
+
+/**
+ * Graph implementation that stacks several graphs and displays them in a cumulative way
+ */
+class StackedGraph implements Drawable
+{
+    /**
+     * All graphs displayed in this stackedgraph
+     *
+     * @var array
+     */
+    private $stack = array();
+
+    /**
+     * An associative array containing x points as the key and an array of y values as the value
+     *
+     * @var array
+     */
+    private $points = array();
+
+    /**
+     * Add a graph to this stack and aggregate the values on the fly
+     *
+     * This modifies the dataset as a side effect
+     *
+     * @param array $subGraph
+     */
+    public function addGraph(array &$subGraph)
+    {
+        foreach ($subGraph['data'] as &$point) {
+            $x = $point[0];
+            if (!isset($this->points[$x])) {
+                $this->points[$x] = 0;
+            }
+            // store old y-value for displaying the actual (non-aggregated)
+            // value in the tooltip
+            $point[2] = $point[1];
+
+            $this->points[$x] += $point[1];
+            $point[1] = $this->points[$x];
+        }
+    }
+
+    /**
+     * Add a graph to the stack
+     *
+     * @param $graph
+     */
+    public function addToStack($graph)
+    {
+        $this->stack[] = $graph;
+    }
+
+    /**
+     * Empty the stack
+     *
+     * @return bool
+     */
+    public function stackEmpty()
+    {
+        return empty($this->stack);
+    }
+
+    /**
+     * Render this stack in the correct order
+     *
+     * @param   RenderContext $ctx  The context to use for rendering
+     *
+     * @return  DOMElement          The SVG representation of this graph
+     */
+    public function toSvg(RenderContext $ctx)
+    {
+        $group = $ctx->getDocument()->createElement('g');
+        $renderOrder = array_reverse($this->stack);
+        foreach ($renderOrder as $stackElem) {
+            $group->appendChild($stackElem->toSvg($ctx));
+        }
+        return $group;
+    }
+}