1 files changed, 87 insertions, 56 deletions

diff --git a/src/transform.js b/src/transform.js
index ded67fb..da2bf37 100644
--- a/src/transform.js
+++ b/src/transform.js
@@ -1,68 +1,99 @@
 SVG.extend(SVG.Element, SVG.FX, {
-	// Add transformations
-	transform: function(o) {
-		// get target in case of the fx module, otherwise reference this
-		var target = this.target || this
+  // Add transformations
+  transform: function(o, relative) {
+    // get target in case of the fx module, otherwise reference this
+    var target = this.target || this
 
-		// full getter
-		if (o == null)
-			return target.ctm().extract()
+    // full getter
+    if (o == null)
+      return target.ctm().extract()
 
-		// singular getter
-		else if (typeof o === 'string')
-			return target.ctm().extract()[o]
-		
-		// get current matrix
-		var matrix = new SVG.Matrix(o.add === true ? target : {})
-		
-		// act on matrix
-		if (o.a != null)
-			matrix = matrix.multiply(new SVG.Matrix(o))
-		
-		// act on rotate
-		else if (o.rotation)
-			matrix = matrix.rotate(
-				o.rotation
-			, o.cx == null ? target.bbox().cx : o.cx
-			, o.cy == null ? target.bbox().cy : o.cy
-			)
-		
-		// act on scale
-		else if (o.scale != null || o.scaleX != null || o.scaleY != null)
-			matrix = matrix.scale(
-				o.scale != null ? o.scale : o.scaleX != null ? o.scaleX : 1
-			, o.scale != null ? o.scale : o.scaleY != null ? o.scaleY : 1
-			, o.cx 		== null ? target.bbox().x : o.cx
-			, o.cy 		== null ? target.bbox().y : o.cy
-			)
+    // singular getter
+    else if (typeof o === 'string')
+      return target.ctm().extract()[o]
 
-		// act on skew
-		else if (o.skewX || o.skewY)
-			matrix = matrix.skew(
-				o.skewX
-			, o.skewY
-			, o.cx == null ? target.bbox().cx : o.cx
-			, o.cy == null ? target.bbox().cy : o.cy
-			)
+    // get current matrix
+    var matrix = new SVG.Matrix(target)
 
-		// act on flip
-		else if (o.flip)
-			matrix = matrix.flip(
-				o.flip
-			, o.offset == null ? target.bbox()['c' + o.flip] : o.offset
-			)
+    // ensure relative flag
+    relative = !!relative || !!o.relative
+    
+    // act on matrix
+    if (o.a != null) {
+      matrix = relative ?
+        // relative
+        matrix.multiply(new SVG.Matrix(o)) :
+        // absolute
+        new SVG.Matrix(o)
+    
+    // act on rotate
+    } else if (o.rotation != null) {
+      o.cx = o.cx == null ? target.bbox().cx : o.cx
+      o.cy = o.cy == null ? target.bbox().cy : o.cy
 
-		// act on translate
-		else if (o.x || o.y)
-			matrix = matrix.translate(o.x, o.y)
+      matrix = relative ?
+        // relative
+        target.attr('transform', matrix + ' rotate(' + [o.rotation, o.cx, o.cy].join() + ')').ctm() :
+        // absolute
+        matrix.rotate(o.rotation - matrix.extract().rotation, o.cx, o.cy)
+    
+    // act on scale
+    } else if (o.scale != null || o.scaleX != null || o.scaleY != null) {
+      o.scaleX = o.scale != null ? o.scale : o.scaleX != null ? o.scaleX : 1
+      o.scaleY = o.scale != null ? o.scale : o.scaleY != null ? o.scaleY : 1
+      o.cx = o.cx == null ? target.bbox().cx : o.cx
+      o.cy = o.cy == null ? target.bbox().cy : o.cy
 
-		return this.attr('transform', matrix)
-	}
+      if (!relative) {
+        // absolute; multiply inversed values
+        var e = matrix.extract()
+        o.scaleX = o.scaleX * 1 / e.scaleX
+        o.scaleY = o.scaleY * 1 / e.scaleY
+      }
+
+      matrix = matrix.scale(o.scaleX, o.scaleY, o.cx, o.cy)
+
+    // act on skew
+    } else if (o.skewX != null || o.skewY != null) {
+      o.skewX = o.skewX != null ? o.skewX : 0
+      o.skewY = o.skewY != null ? o.skewY : 0
+      o.cx = o.cx == null ? target.bbox().cx : o.cx
+      o.cy = o.cy == null ? target.bbox().cy : o.cy
+
+      if (!relative) {
+        // absolute; reset skew values
+        var e = matrix.extract()
+        matrix = matrix.multiply(new SVG.Matrix().skew(e.skewX, e.skewY, o.cx, o.cy).inverse())
+      }
+      
+      matrix = matrix.skew(o.skewX, o.skewY, o.cx, o.cy)
+
+    // act on flip
+    } else if (o.flip) {
+      matrix = matrix.flip(
+        o.flip
+      , o.offset == null ? target.bbox()['c' + o.flip] : o.offset
+      )
+
+    // act on translate
+    } else if (o.x != null || o.y != null) {
+      if (relative) {
+        // relative
+        matrix = matrix.translate(o.x, o.y)
+      } else {
+        // absolute
+        if (o.x != null) matrix.e = o.x
+        if (o.y != null) matrix.f = o.y
+      }
+    }
+
+    return this.attr('transform', matrix)
+  }
 })
 
 SVG.extend(SVG.Element, {
-	// Reset all transformations
+  // Reset all transformations
   untransform: function() {
-		return this.attr('transform', null)
-	}
+    return this.attr('transform', null)
+  }
 })
\ No newline at end of file