From 2283a216a32493450adf1b35462e985767b5bf54 Mon Sep 17 00:00:00 2001
From: Fabian Meyer <3982806+meyfa@users.noreply.github.com>
Date: Wed, 31 Jan 2018 13:48:10 +0100
Subject: [PATCH] Add getElementsByTagName method to nodes

---
 src/Nodes/SVGNode.php                | 19 +++++++++++++++
 src/Nodes/SVGNodeContainer.php       | 12 ++++++++++
 tests/Nodes/SVGNodeContainerTest.php | 36 ++++++++++++++++++++++++++++
 3 files changed, 67 insertions(+)

diff --git a/src/Nodes/SVGNode.php b/src/Nodes/SVGNode.php
index 7125dab..e4a8a4a 100644
--- a/src/Nodes/SVGNode.php
+++ b/src/Nodes/SVGNode.php
@@ -263,4 +263,23 @@ public function getViewBox()
      * @return void
      */
     abstract public function rasterize(SVGRasterizer $rasterizer);
+
+    /**
+     * Returns all descendants of this node (excluding this node) having the
+     * given tag name. '*' matches all nodes.
+     *
+     * Example: getElementsByTagName('rect')
+     * would return all <rect /> nodes that are descendants of this node.
+     *
+     * @param string $tagName The tag name to search for ('*' to match all).
+     * @param SVGNode[] $result The array to fill. Can be omitted.
+     *
+     * @return SVGNode[] An array of matching elements.
+     *
+     * @SuppressWarnings("unused")
+     */
+    public function getElementsByTagName($tagName, array &$result = array())
+    {
+        return $result;
+    }
 }
diff --git a/src/Nodes/SVGNodeContainer.php b/src/Nodes/SVGNodeContainer.php
index 6aba95b..ef09098 100644
--- a/src/Nodes/SVGNodeContainer.php
+++ b/src/Nodes/SVGNodeContainer.php
@@ -196,4 +196,16 @@ private function pregGrepStyle($pattern)
     {
         return preg_grep($pattern, array_keys($this->containerStyles));
     }
+
+    public function getElementsByTagName($tagName, array &$result = array())
+    {
+        foreach ($this->children as $child) {
+            if ($tagName === '*' || $child->getName() === $tagName) {
+                $result[] = $child;
+            }
+            $child->getElementsByTagName($tagName, $result);
+        }
+
+        return $result;
+    }
 }
diff --git a/tests/Nodes/SVGNodeContainerTest.php b/tests/Nodes/SVGNodeContainerTest.php
index 60f2212..4f7473e 100644
--- a/tests/Nodes/SVGNodeContainerTest.php
+++ b/tests/Nodes/SVGNodeContainerTest.php
@@ -80,4 +80,40 @@ public function testRasterize()
         $obj->setStyle('display', 'none');
         $obj->rasterize($rast);
     }
+
+    public function testGetElementsByTagName()
+    {
+        $obj = new SVGNodeContainerSubclass();
+        $obj->addChild(
+            ($root_0 = new \SVG\Nodes\Structures\SVGGroup())->addChild(
+                $root_0_0 = new \SVG\Nodes\Shapes\SVGLine()
+            )->addChild(
+                $root_0_1 = new \SVG\Nodes\Shapes\SVGRect()
+            )
+        );
+        $obj->addChild(
+            ($root_1 = new \SVG\Nodes\Structures\SVGGroup())->addChild(
+                ($root_1_0 = new \SVG\Nodes\Structures\SVGGroup())->addChild(
+                    $root_1_0_0 = new \SVG\Nodes\Shapes\SVGRect()
+                )
+            )->addChild(
+                $root_1_1 = new \SVG\Nodes\Shapes\SVGRect()
+            )
+        );
+
+        // should not return itself
+        $this->assertSame(array(), $obj->getElementsByTagName('test_subclass'));
+        $this->assertNotContains($obj, $obj->getElementsByTagName('*'));
+
+        // should return specific tags
+        $this->assertSame(array(
+            $root_0_1, $root_1_0_0, $root_1_1,
+        ), $obj->getElementsByTagName('rect'));
+
+        // should return all descendants for '*'
+        $this->assertSame(array(
+            $root_0, $root_0_0, $root_0_1,
+            $root_1, $root_1_0, $root_1_0_0, $root_1_1,
+        ), $obj->getElementsByTagName('*'));
+    }
 }