Added .skewX() & skewY() shortcuts

CHANGELOG.md

@@ -1,3 +1,11 @@
+2.2.0 / WIP
+------------------
+
+- Added `.skewX()` & `.skewY()` shortcuts.
+- Dropped `Makefile`, use npm instead.
+- Deps bump & cleanup.
+
+
 2.1.6 / 2016-03-09
 ------------------
 

README.md

@@ -70,10 +70,20 @@ Rescale path (the same as SVG `translate` transformation). `y` = 0 by default.
 
 ### .rotate(angle [, rx, ry]) -> self
 
-Rotate path to `angle` degree around (rx, ry) point. If rotation center not set,
+Rotate path to `angle` degrees around (rx, ry) point. If rotation center not set,
 (0, 0) used. The same as SVG `rotate` transformation.
 
 
+### .skewX(degrees) -> self
+
+Skew path along the X axis by `degrees` angle.
+
+
+### .skewY(degrees) -> self
+
+Skew path along the Y axis by `degrees` angle.
+
+
 ### .matrix([ m1, m2, m3, m4, m5, m6 ]) -> self
 
 Apply 2x3 affine transform matrix to path. Params - array. The same as SVG

lib/svgpath.js

@@ -216,6 +216,22 @@ SvgPath.prototype.rotate = function (angle, rx, ry) {
 };
 
 
+// Skew path along the X axis by `degrees` angle
+//
+SvgPath.prototype.skewX = function (degrees) {
+  this.__stack.push(matrix().skewX(degrees));
+  return this;
+};
+
+
+// Skew path along the Y axis by `degrees` angle
+//
+SvgPath.prototype.skewY = function (degrees) {
+  this.__stack.push(matrix().skewY(degrees));
+  return this;
+};
+
+
 // Apply matrix transform (array of 6 elements)
 //
 SvgPath.prototype.matrix = function (m) {

test/api.js

@@ -269,6 +269,28 @@ describe('API', function () {
     });
   });
 
+  describe('skew', function () {
+    // SkewX matrix [ 1, 0, 4, 1, 0, 0 ],
+    // x = x*1 + y*4 + 0 = x + y*4
+    // y = x*0 + y*1 + 0 = y
+    it('skewX', function () {
+      assert.equal(
+        svgpath('M5 5L15 20').skewX(75.96).round(0).toString(),
+        'M25 5L95 20'
+      );
+    });
+
+    // SkewY matrix [ 1, 4, 0, 1, 0, 0 ],
+    // x = x*1 + y*0 + 0 = x
+    // y = x*4 + y*1 + 0 = y + x*4
+    it('skewY', function () {
+      assert.equal(
+        svgpath('M5 5L15 20').skewY(75.96).round(0).toString(),
+        'M5 25L15 80'
+      );
+    });
+  });
+
 
   describe('matrix', function () {
     // x = x*1.5 + y/2 + ( absolute ? 10 : 0)