From: Evert Timberg <evert.timberg+github@gmail.com>
Date: Sat, 9 Jul 2016 21:24:41 +0000 (-0400)
Subject: Bring back capping of bezier curve points and have an option to disable it (#2948)
X-Git-Tag: v2.2.0-rc.1~8
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=49c4169010048d1fb4add298ec1f680b6dd6d30a;p=thirdparty%2FChart.js.git

Bring back capping of bezier curve points and have an option to disable it (#2948)
---

diff --git a/docs/01-Chart-Configuration.md b/docs/01-Chart-Configuration.md
index 57c06284d..5a8627456 100644
--- a/docs/01-Chart-Configuration.md
+++ b/docs/01-Chart-Configuration.md
@@ -369,6 +369,7 @@ borderCapStyle | String | 'butt' | Default line cap style. See [MDN](https://dev
 borderDash | Array | `[]` | Default line dash. See [MDN](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/setLineDash)
 borderDashOffset | Number | 0.0 | Default line dash offset. See [MDN](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/lineDashOffset)
 borderJoinStyle | String | 'miter' | Default line join style. See [MDN](https://developer.mozilla.org/en-US/docs/Web/API/CanvasRenderingContext2D/lineJoin)
+capBezierPoints | Boolean | true | If true, bezier control points are kept inside the chart. If false, no restriction is enforced.
 fill | Boolean | true | If true, the line is filled.
 stepped | Boolean | false | If true, the line is shown as a steeped line and 'tension' will be ignored
 
diff --git a/src/controllers/controller.line.js b/src/controllers/controller.line.js
index caee9c683..b184aff03 100644
--- a/src/controllers/controller.line.js
+++ b/src/controllers/controller.line.js
@@ -244,10 +244,17 @@ module.exports = function(Chart) {
 		},
 
 		updateBezierControlPoints: function() {
-			var meta = this.getMeta();
+			var me = this;
+			var meta = me.getMeta();
+			var area = me.chart.chartArea;
 			var points = meta.data || [];
 			var i, ilen, point, model, controlPoints;
 
+			var needToCap = me.chart.options.elements.line.capBezierPoints;
+			function capIfNecessary(pt, min, max) {
+				return needToCap ? Math.max(Math.min(pt, max), min) : pt;
+			}
+
 			for (i=0, ilen=points.length; i<ilen; ++i) {
 				point = points[i];
 				model = point._model;
@@ -258,10 +265,10 @@ module.exports = function(Chart) {
 					meta.dataset._model.tension
 				);
 
-				model.controlPointPreviousX = controlPoints.previous.x;
-				model.controlPointPreviousY = controlPoints.previous.y;
-				model.controlPointNextX = controlPoints.next.x;
-				model.controlPointNextY = controlPoints.next.y;
+				model.controlPointPreviousX = capIfNecessary(controlPoints.previous.x, area.left, area.right);
+				model.controlPointPreviousY = capIfNecessary(controlPoints.previous.y, area.top, area.bottom);
+				model.controlPointNextX = capIfNecessary(controlPoints.next.x, area.left, area.right);
+				model.controlPointNextY = capIfNecessary(controlPoints.next.y, area.top, area.bottom);
 			}
 		},
 
diff --git a/src/elements/element.line.js b/src/elements/element.line.js
index 21a609544..dc8228feb 100644
--- a/src/elements/element.line.js
+++ b/src/elements/element.line.js
@@ -14,6 +14,7 @@ module.exports = function(Chart) {
 		borderDash: [],
 		borderDashOffset: 0.0,
 		borderJoinStyle: 'miter',
+		capBezierPoints: true,
 		fill: true // do we fill in the area between the line and its base axis
 	};