1 files changed, 13 insertions, 11 deletions

diff --git a/src/line.js b/src/line.js
index 7407983..893fe62 100644
--- a/src/line.js
+++ b/src/line.js
@@ -11,35 +11,37 @@ SVG.extend(SVG.Line, {
   x: function(x) {
     var b = this.bbox()
     
-    return this.attr({
-      x1: this.attrs.x1 - b.x + x
-    , x2: this.attrs.x2 - b.x + x
+    return x == null ? b.x : this.attr({
+      x1: this.attr('x1') - b.x + x
+    , x2: this.attr('x2') - b.x + x
     })
   }
   // Move over y-axis
 , y: function(y) {
     var b = this.bbox()
     
-    return this.attr({
-      y1: this.attrs.y1 - b.y + y
-    , y2: this.attrs.y2 - b.y + y
+    return y == null ? b.y : this.attr({
+      y1: this.attr('y1') - b.y + y
+    , y2: this.attr('y2') - b.y + y
     })
   }
   // Move by center over x-axis
 , cx: function(x) {
-    return this.x(x - this.bbox().width / 2)
+    var half = this.bbox().width / 2
+    return x == null ? this.x() + half : this.x(x - half)
   }
   // Move by center over y-axis
 , cy: function(y) {
-    return this.y(y - this.bbox().height / 2)
+    var half = this.bbox().height / 2
+    return y == null ? this.y() + half : this.y(y - half)
   }
   // Set line size by width and height
 , size: function(width, height) {
     var b = this.bbox()
     
     return this
-      .attr(this.attrs.x1 < this.attrs.x2 ? 'x2' : 'x1', b.x + width)
-      .attr(this.attrs.y1 < this.attrs.y2 ? 'y2' : 'y1', b.y + height)
+      .attr(this.attr('x1') < this.attr('x2') ? 'x2' : 'x1', b.x + width)
+      .attr(this.attr('y1') < this.attr('y2') ? 'y2' : 'y1', b.y + height)
   }
   
-})
\ No newline at end of file
+})