Add support for Tooltip positioners for Chart.Js

types/chart.js/chart.js-tests.ts

@@ -65,3 +65,23 @@ if (chart.chartArea) {
     console.log(chart.chartArea.bottom);
     console.log(chart.chartArea.left);
 }
+
+// http://www.chartjs.org/docs/latest/configuration/tooltip.html#position-modes
+/**
+ * Custom positioner
+ * @function Chart.Tooltip.positioners.custom
+ * @param elements {Chart.Element[]} the tooltip elements
+ * @param eventPosition {Point} the position of the event in canvas coordinates
+ * @returns {Point} the tooltip position
+ */
+Chart.Tooltip.positioners.custom = function(elements: any, eventPosition: any) {
+    /** @type {Chart.Tooltip} */
+    var tooltip = this;
+
+    /* ... */
+
+    return {
+        x: 0,
+        y: 0
+    };
+}

types/chart.js/index.d.ts

@@ -44,6 +44,9 @@ declare class Chart {
     static controllers: {
         [key: string]: any;
     };
+
+    // Tooltip Static Options
+    static Tooltip: Chart.ChartTooltipsStaticConfiguartion;
 }
 declare class PluginServiceStatic {
     register(plugin: PluginServiceRegistrationOptions): void;
@@ -275,6 +278,10 @@ declare namespace Chart {
         borderWidth?: number;
     }
 
+    interface ChartTooltipsStaticConfiguartion {
+        positioners: any;
+    }
+
     interface ChartHoverOptions {
         mode?: string;
         animationDuration?: number;