Adding support to -distort command

README.md

@@ -126,6 +126,22 @@ gm(200, 400, "#ddff99f3")
 .write("/path/to/brandNewImg.jpg", function (err) {
   // ...
 });
+
+// distorting an image
+// array of arrays with from -> to objects
+// fx,fy -> tx,ty
+
+// It will only works with imageMagick subclass
+gm("image.jpg")
+.distort([
+    [{x:99,y:71}, {x:0,y:0}],
+    [{x:299,y:71}, {x:479,y:0}],
+    [{x:100,y:270}, {x:0,y:477}],
+    [{x:299,y:270}, {x:479,y:476}],
+])
+.write("/path/to/brandNewImg.jpg", function (err) {
+  // ...
+});
 ```
 
 ## Streams

lib/args.js

@@ -1103,6 +1103,28 @@ module.exports = function (proto) {
   proto.background = function background (color) {
     return this.in("-background", color);
   }
+
+  //http://www.imagemagick.org/Usage/distorts/
+  proto.distort = function distort(pers, method){
+    if(!method){
+       method = "BilinearForward";
+    }
+    if(!this._options.imageMagick){
+      console.warn('Graphics Magick appears not to support the -distort option. Please use {imageMagick: true}\nDistort command was ignored!');
+      return this;
+    }
+    var perspectiveFrom = "";
+    pers.forEach(function(coordinate){
+      perspectiveFrom  += coordinate[0].x.toString();
+      perspectiveFrom  += ","
+      perspectiveFrom  += coordinate[0].y.toString() +" ";
+      perspectiveFrom  += coordinate[1].x.toString();
+      perspectiveFrom  += ","
+      perspectiveFrom  += coordinate[1].y.toString() +" ";
+    });
+
+    return this.out("-distort",method, perspectiveFrom.trim() );
+  }
 };
 
 /**