From 3ca46cc49eba509392e5d1f170dd68528567c9d1 Mon Sep 17 00:00:00 2001
From: Ahmed Ali <kingcocomango@gmail.com>
Date: Thu, 26 Jul 2018 10:16:22 +0200
Subject: [PATCH] Allow tooltip on label, hide labels for small slices,
 innerlabels for big slices

---
 src/classes.js     |  8 +++++---
 src/plugin.js      | 43 ++++++++++++++++++++++++++++++++++++++++++-
 src/positioners.js |  4 ++--
 3 files changed, 49 insertions(+), 6 deletions(-)

diff --git a/src/classes.js b/src/classes.js
index 0122910..68782b4 100644
--- a/src/classes.js
+++ b/src/classes.js
@@ -94,14 +94,15 @@ export default {
 			this.predictedOffset = this.offset;
 
 			var angle = -((el._model.startAngle + el._model.endAngle) / 2) / (Math.PI);
+			let innerLabel = el._model.circumference > 0.5;
 			var val = Math.abs(angle - Math.trunc(angle));
 
 			if (val > 0.45 && val < 0.55) {
 				this.predictedOffset.x = 0;
 			} else if (angle <= 0.45 && angle >= -0.45) {
-				this.predictedOffset.x = this.size.width / 2;
+				this.predictedOffset.x = this.size.width / (innerLabel ? -2 : 2);
 			} else if (angle >= -1.45 && angle <= -0.55) {
-				this.predictedOffset.x = -this.size.width / 2;
+				this.predictedOffset.x = -this.size.width / (innerLabel ? -2 : 2);
 			}
 		};
 
@@ -255,7 +256,8 @@ export default {
 
 
 		this.update = function(view, elements, max) {
-			this.center = positioners.center(view, this.stretch);
+			let innerLabel = el._model.circumference > 0.5;
+			this.center = positioners.center(view, this.stretch, innerLabel);
 			this.moveLabelToOffset();
 
 			this.center.x += this.offset.x;
diff --git a/src/plugin.js b/src/plugin.js
index fa3a16a..546933d 100644
--- a/src/plugin.js
+++ b/src/plugin.js
@@ -13,6 +13,7 @@ outlabeledCharts.init();
 Chart.defaults.global.plugins.outlabels = defaults;
 
 var LABEL_KEY = defaults.LABEL_KEY;
+let activeTooltip = null;
 
 function configure(dataset, options) {
 	var override = dataset.outlabels;
@@ -35,6 +36,46 @@ Chart.plugins.register({
 		chart.sizeChanged = true;
 	},
 
+	beforeEvent: function(chart, event, options) {
+		const {
+			x,
+			y
+		} = event;
+
+		const {
+			tooltipToggle,
+			toggleOffDistance
+		} = options;
+
+		const elems = chart.getDatasetMeta(0).data;
+		let center, data;
+
+		if (activeTooltip && (Math.abs(activeTooltip.x - x) > toggleOffDistance || Math.abs(activeTooltip.y - y) > toggleOffDistance)) {
+			tooltipToggle(null, null);
+			activeTooltip = null;
+		}
+		for (let i = 0; i < elems.length; i++) {
+			if (!elems[i].$outlabels) {
+				continue;
+			}
+			const within = elems[i].$outlabels.containsPoint({
+				x: event.x,
+				y: event.y,
+			});
+			if (within) {
+				center = elems[i].$outlabels.center;
+				const index = elems[i]._index;
+				data = chart.data.labels[index];
+				tooltipToggle(center, data);
+				activeTooltip = center;
+				return;
+			}
+		}
+
+		return;
+	},
+
+
 	afterDatasetUpdate: function(chart, args, options) {
 		var labels = chart.config.data.labels;
 		var dataset = chart.data.datasets[args.index];
@@ -52,7 +93,7 @@ Chart.plugins.register({
 			percent = dataset.data[i] / args.meta.total;
 			newLabel = null;
 
-			if (display && el && !el.hidden) {
+			if (display && el && !el.hidden && el._model.circumference > options.tooltipCutoff) {
 				try {
 					context = {
 						chart: chart,
diff --git a/src/positioners.js b/src/positioners.js
index b1d3dbd..8c917aa 100644
--- a/src/positioners.js
+++ b/src/positioners.js
@@ -1,13 +1,13 @@
 'use strict';
 
 export default {
-	center: function(arc, stretch) {
+	center: function(arc, stretch, invert) {
 		var angle = (arc.startAngle + arc.endAngle) / 2;
 		var cosA = Math.cos(angle);
 		var sinA = Math.sin(angle);
 		var d = arc.outerRadius;
 
-		var stretchedD = d + stretch;
+		var stretchedD = invert ? d - stretch : d + stretch;
 		return {
 			x: arc.x + cosA * stretchedD,
 			y: arc.y + sinA * stretchedD,