Compare distance between cursor with absolute value. (#4295)

* fix with Math.abs

* ok this works

* added test

* added test file

* linting tests

* wrong test

src/mixins/itext_click_behavior.mixin.js

@@ -196,10 +196,11 @@ fabric.util.object.extend(fabric.IText.prototype, /** @lends fabric.IText.protot
    * @private
    */
   _getNewSelectionStartFromOffset: function(mouseOffset, prevWidth, width, index, jlen) {
-
+    // we need Math.abs because when width is after the last char, the offset is given as 1, while is 0
     var distanceBtwLastCharAndCursor = mouseOffset.x - prevWidth,
         distanceBtwNextCharAndCursor = width - mouseOffset.x,
-        offset = distanceBtwNextCharAndCursor > distanceBtwLastCharAndCursor ? 0 : 1,
+        offset = distanceBtwNextCharAndCursor > distanceBtwLastCharAndCursor ||
+          distanceBtwNextCharAndCursor < 0 ? 0 : 1,
         newSelectionStart = index + offset;
     // if object is horizontally flipped, mirror cursor location from the end
     if (this.flipX) {

test.js

@@ -39,6 +39,7 @@ testrunner.run({
       './test/unit/object_geometry.js',
       './test/unit/object_origin.js',
       './test/unit/itext.js',
+      './test/unit/itext_click_behaviour.js',
       './test/unit/itext_key_behaviour.js',
       './test/unit/collection.js',
       './test/unit/point.js',

test/unit/itext_click_behaviour.js

@@ -0,0 +1,30 @@
+(function(){
+  test('_getNewSelectionStartFromOffset end of line', function() {
+    var iText = new fabric.IText('test need some word\nsecond line');
+    var index = 10;
+    var jlen = 20;
+    var selection = iText._getNewSelectionStartFromOffset({ y: 1, x: 1000 }, 500, 520, index, jlen);
+    equal(selection, index, 'index value did not change');
+  });
+  test('_getNewSelectionStartFromOffset middle of line', function() {
+    var iText = new fabric.IText('test need some word\nsecond line');
+    var index = 10;
+    var jlen = 20;
+    var selection = iText._getNewSelectionStartFromOffset({ y: 1, x: 519 }, 500, 520, index, jlen);
+    equal(selection, index + 1, 'index value was moved to next char, since is very near');
+  });
+  test('_getNewSelectionStartFromOffset middle of line', function() {
+    var iText = new fabric.IText('test need some word\nsecond line');
+    var index = 10;
+    var jlen = 20;
+    var selection = iText._getNewSelectionStartFromOffset({ y: 1, x: 502 }, 500, 520, index, jlen);
+    equal(selection, index, 'index value was NOT moved to next char, since is very near to first one');
+  });
+  test('_getNewSelectionStartFromOffset middle of line', function() {
+    var iText = new fabric.IText('test need some word\nsecond line');
+    var index = 10;
+    var jlen = 10;
+    var selection = iText._getNewSelectionStartFromOffset({ y: 1, x: 1000 }, 500, 520, index, jlen);
+    equal(selection, index, 'index value was NOT moved to next char, since is already at end of text');
+  });
+})();