Added merge() to SVG.BBox

3 files changed, 86 insertions, 43 deletions

diff --git a/src/bbox.js b/src/bbox.js
index 22c5bcf..b05e90c 100644
--- a/src/bbox.js
+++ b/src/bbox.js
@@ -1,29 +1,61 @@
 
 SVG.BBox = function(element) {
   var box
+
+  /* initialize zero box */
+  this.x      = 0
+  this.y      = 0
+  this.width  = 0
+  this.height = 0
   
-  /* actual, native bounding box */
-  try {
-    box = element.node.getBBox()
-  } catch(e) {
-    box = {
-      x:      element.node.clientLeft
-    , y:      element.node.clientTop
-    , width:  element.node.clientWidth
-    , height: element.node.clientHeight
+  /* get values if element is given */
+  if (element) {
+    try {
+      /* actual, native bounding box */
+      box = element.node.getBBox()
+    } catch(e) {
+      /* fallback for some browsers */
+      box = {
+        x:      element.node.clientLeft
+      , y:      element.node.clientTop
+      , width:  element.node.clientWidth
+      , height: element.node.clientHeight
+      }
     }
+    
+    /* include translations on x an y */
+    this.x = box.x + element.trans.x
+    this.y = box.y + element.trans.y
+    
+    /* plain width and height */
+    this.width  = box.width  * element.trans.scaleX
+    this.height = box.height * element.trans.scaleY
   }
   
-  /* include translations on x an y */
-  this.x = box.x + element.trans.x
-  this.y = box.y + element.trans.y
-  
-  /* plain width and height */
-  this.width  = box.width  * element.trans.scaleX
-  this.height = box.height * element.trans.scaleY
-  
   /* add the center */
   this.cx = this.x + this.width / 2
   this.cy = this.y + this.height / 2
   
-}
\ No newline at end of file
+}
+
+//
+SVG.extend(SVG.BBox, {
+  // merge bounding box with another, return a new instance
+  merge: function(box) {
+    var b = new SVG.BBox()
+
+    /* merge box */
+    b.x      = Math.min(this.x, box.x)
+    b.y      = Math.min(this.y, box.y)
+    b.width  = Math.max(this.x + this.width,  box.x + box.width)  - b.x
+    b.height = Math.max(this.y + this.height, box.y + box.height) - b.y
+
+    /* add the center */
+    b.cx = b.x + b.width / 2
+    b.cy = b.y + b.height / 2
+
+    return b
+  }
+
+})
+
diff --git a/src/element.js b/src/element.js
index 3149d22..8d07762 100644
--- a/src/element.js
+++ b/src/element.js
@@ -178,6 +178,7 @@ SVG.extend(SVG.Element, {
   }
   // Manage transformations
 , transform: function(o, v) {
+    
     if (arguments.length == 0) {
       /* act as a getter if no argument is given */
       return this.trans
diff --git a/src/rbox.js b/src/rbox.js
index 02405b0..5eb474f 100644
--- a/src/rbox.js
+++ b/src/rbox.js
@@ -1,32 +1,42 @@
 // Get the rectangular box of a given element
 SVG.RBox = function(element) {
-  var box, zoom
-    , e = element.doc().parent
-    , zoom = element.doc().viewbox().zoom
-  
-  /* actual, native bounding box */
-  box = element.node.getBoundingClientRect()
-  
-  /* get screen offset */
-  this.x = box.left
-  this.y = box.top
-  
-  /* subtract parent offset */
-  this.x -= e.offsetLeft
-  this.y -= e.offsetTop
-  
-  while (e = e.offsetParent) {
+  var e, zoom
+    , box = {}
+
+  /* initialize zero box */
+  this.x      = 0
+  this.y      = 0
+  this.width  = 0
+  this.height = 0
+  
+  if (element) {
+    e = element.doc().parent
+    zoom = element.doc().viewbox().zoom
+    
+    /* actual, native bounding box */
+    box = element.node.getBoundingClientRect()
+    
+    /* get screen offset */
+    this.x = box.left
+    this.y = box.top
+    
+    /* subtract parent offset */
     this.x -= e.offsetLeft
     this.y -= e.offsetTop
-  }
-  
-  /* calculate cumulative zoom from svg documents */
-  e = element
-  while (e = e.parent) {
-    if (e.type == 'svg' && e.viewbox) {
-      zoom *= e.viewbox().zoom
-      this.x -= e.x() || 0
-      this.y -= e.y() || 0
+    
+    while (e = e.offsetParent) {
+      this.x -= e.offsetLeft
+      this.y -= e.offsetTop
+    }
+    
+    /* calculate cumulative zoom from svg documents */
+    e = element
+    while (e = e.parent) {
+      if (e.type == 'svg' && e.viewbox) {
+        zoom *= e.viewbox().zoom
+        this.x -= e.x() || 0
+        this.y -= e.y() || 0
+      }
     }
   }