1 files changed, 102 insertions, 0 deletions
diff --git a/library/Icinga/Chart/Legend.php b/library/Icinga/Chart/Legend.php
new file mode 100644
index 0000000..ab1c9e0
--- /dev/null
+++ b/library/Icinga/Chart/Legend.php
@@ -0,0 +1,102 @@
+<?php
+/* Icinga Web 2 | (c) 2013 Icinga Development Team | GPLv2+ */
+
+namespace Icinga\Chart;
+
+use DOMElement;
+use Icinga\Chart\Palette;
+use Icinga\Chart\Primitive\Canvas;
+use Icinga\Chart\Primitive\Drawable;
+use Icinga\Chart\Primitive\Rect;
+use Icinga\Chart\Primitive\Text;
+use Icinga\Chart\Render\LayoutBox;
+use Icinga\Chart\Render\RenderContext;
+
+/**
+ * Drawable for creating a Graph Legend on the bottom of a graph.
+ *
+ * Usually used by the GridChart class internally.
+ */
+class Legend implements Drawable
+{
+
+    /**
+     * Internal counter for unnamed label identifiers
+     *
+     * @var int
+     */
+    private $internalCtr = 0;
+
+    /**
+     *
+     * Content of this legend
+     *
+     * @var array
+     */
+    private $dataset = array();
+
+
+    /**
+     * Set the content to be displayed by this legend
+     *
+     * @param array $dataset An array of datasets in the form they are provided to the graphing implementation
+     */
+    public function addDataset(array $dataset)
+    {
+        if (!isset($dataset['label'])) {
+            $dataset['label'] = 'Dataset ' . (++$this->internalCtr);
+        }
+        if (!isset($dataset['color'])) {
+            return;
+        }
+        $this->dataset[$dataset['color']] = $dataset['label'];
+    }
+
+    /**
+     * Render the legend to an SVG object
+     *
+     * @param   RenderContext $ctx  The context to use for rendering this legend
+     *
+     * @return  DOMElement          The SVG representation of this legend
+     */
+    public function toSvg(RenderContext $ctx)
+    {
+        $outer = new Canvas('legend', new LayoutBox(0, 0, 100, 100));
+        $outer->getLayout()->setPadding(2, 2, 2, 2);
+        $nrOfColumns = 4;
+
+        $topstep = 10 / $nrOfColumns + 2;
+
+        $top = 0;
+        $left = 0;
+        $lastLabelEndPos = -1;
+        foreach ($this->dataset as $color => $text) {
+            $leftstep = 100 / $nrOfColumns + strlen($text);
+
+            // Make sure labels don't overlap each other
+            while ($lastLabelEndPos >= $left) {
+                $left += $leftstep;
+            }
+            // When a label is longer than the available space, use the next line
+            if ($left + strlen($text) > 100) {
+                $top += $topstep;
+                $left = 0;
+            }
+
+            $colorBox = new Rect($left, $top, 2, 2);
+            $colorBox->setFill($color)->setStrokeWidth(2);
+            $colorBox->keepRatio();
+            $outer->addElement($colorBox);
+
+            $textBox = new Text($left+5, $top+2, $text);
+            $textBox->setFontSize('2em');
+            $outer->addElement($textBox);
+
+            // readjust layout
+            $lastLabelEndPos = $left + strlen($text);
+            $left += $leftstep;
+        }
+        $svg = $outer->toSvg($ctx);
+        return $svg;
+    }
+}