add SetMiterLimit functionality to pdf and context2d (#2162)

* Update jspdf.js

* Update context2d.js

* Update jspdf.unit.spec.js

* Add files via upload

* Add files via upload

Author: Uzlopak

src/jspdf.js

@@ -3155,6 +3155,28 @@ var jsPDF = (function (global) {
       return this;
     };
 
+    var miterLimit;
+    /**
+     * Sets the miterLimit property, which effects the maximum miter length.
+     *
+     * @param {number} length The length of the miter
+     * @function
+     * @instance
+     * @returns {jsPDF}
+     * @memberOf jsPDF
+     * @name setMiterLimit
+     */
+    var setMiterLimit = API.__private__.setMiterLimit = API.setMiterLimit = function (length) {
+      length = length || 0;
+      if (isNaN(length)) {
+        throw new Error('Invalid argument passed to jsPDF.setMiterLimit');
+      }
+      miterLimit = parseFloat(f2(length * k));
+      out(miterLimit + ' M');
+
+      return this;
+    };
+
     /**
      * Saves as PDF document. An alias of jsPDF.output('save', 'filename.pdf').
      * Uses FileSaver.js-method saveAs.

src/modules/context2d.js

@@ -352,6 +352,7 @@
             set: function (value) {
                 if (!isNaN(value)) {
                     this.ctx.miterLimit = value;
+                    this.pdf.setMiterLimit(value);
                 }
             }
         });

tests/context2d/reference/bar_graph_with_text_and_lines.pdf

@@ -1171,6 +1171,19 @@ break`, 10, 10, {scope: doc});
 
   })
 
+  it('jsPDF private function setMiterLimit', () => {
+    var doc = jsPDF();
+
+    var writeArray;
+    
+    //miter/butt
+    doc = jsPDF();
+    writeArray = [];
+    doc.__private__.setCustomOutputDestination(writeArray);
+    doc.__private__.setMiterLimit(1);
+    expect(writeArray).toEqual(['2.83 M']);
+    expect(function() {doc.__private__.setMiterLimit('invalid');}).toThrow(new Error('Invalid argument passed to jsPDF.setMiterLimit')); 
+  })
   it('jsPDF private function putHeader', () => {
     var doc = jsPDF();