fastline controller

Author: benmccann

src/controllers/controller.fastline.js

@@ -0,0 +1,74 @@
+'use strict';
+
+const Line = require('../elements/element.line');
+const LineController = require('./controller.line');
+const defaults = require('../core/core.defaults');
+
+defaults.fastline = defaults.line;
+
+module.exports = LineController.extend({
+
+	addElements: function() {},
+
+	insertElements: function(start, count) {
+		this._parse(start, count);
+	},
+
+	/**
+	 * @private
+	 */
+	_getMinMax: function(scale) {
+		const meta = this._cachedMeta;
+		const {_parsed} = meta;
+		const ilen = _parsed.length;
+		const isIndexScale = scale === meta.iScale;
+		let min = Number.POSITIVE_INFINITY;
+		let max = Number.NEGATIVE_INFINITY;
+		let i, value;
+
+
+		if (isIndexScale) {
+			if (ilen > 0) {
+				min = _parsed[0][scale.axis];
+				max = _parsed[ilen - 1][scale.axis];
+			}
+		} else {
+			for (i = 0; i < ilen; ++i) {
+				value = _parsed[i][scale.id];
+				min = Math.min(min, value);
+				max = Math.max(max, value);
+			}
+		}
+
+		return {min, max};
+	},
+
+	update: function() {
+		const me = this;
+		me._cachedMeta._options = me._resolveDatasetElementOptions();
+	},
+
+	draw: function() {
+		const me = this;
+		const ctx = me._ctx;
+		const meta = me._cachedMeta;
+		const {xScale, yScale, _stacked} = meta;
+		const options = meta._options;
+		let i = 0;
+
+		ctx.save();
+		Line._setStyle(ctx, options);
+		ctx.beginPath();
+
+		for (i = 0; i < meta._parsed.length; ++i) {
+			const parsed = me._getParsed(i);
+			const x = xScale.getPixelForValue(parsed[xScale.id]);
+			const y = yScale.getPixelForValue(_stacked ? me._applyStack(yScale, parsed) : parsed[yScale.id]);
+
+			ctx.lineTo(x, y);
+		}
+
+		ctx.stroke();
+		ctx.restore();
+	}
+});

src/controllers/index.js

@@ -5,6 +5,7 @@ var bubble = require('./controller.bubble');
 var doughnut = require('./controller.doughnut');
 var horizontalBar = require('./controller.horizontalBar');
 var line = require('./controller.line');
+var fastline = require('./controller.fastline');
 var polarArea = require('./controller.polarArea');
 var pie = require('./controller.pie');
 var radar = require('./controller.radar');
@@ -19,6 +20,7 @@ module.exports = {
 	bubble: bubble,
 	doughnut: doughnut,
 	horizontalBar: horizontalBar,
+	fastline: fastline,
 	line: line,
 	polarArea: polarArea,
 	pie: pie,

src/core/core.interaction.js

@@ -3,6 +3,16 @@
 import helpers from '../helpers/index';
 import {isNumber} from '../helpers/helpers.math';
 
+function getOrCreateElement(metaset, index) {
+	let element = metaset.data[index];
+	if (!element) {
+		const controller = metaset.controller;
+		element = new controller.dataElementType();
+		controller.updateElements([element], index);
+	}
+	return element;
+}
+
 /**
  * Helper function to get relative position for an event
  * @param {Event|IEvent} event - The event to get the position for
@@ -65,7 +75,7 @@ function evaluateItemsAtIndex(chart, axis, position, handler) {
 	for (let i = 0, ilen = metasets.length; i < ilen; ++i) {
 		const metaset = metasets[i];
 		const index = indices[i];
-		const element = metaset.data[index];
+		let element = getOrCreateElement(metaset, index);
 		if (!element.skip) {
 			handler(element, metaset.index, index);
 		}
@@ -190,7 +200,7 @@ export default {
 
 			chart._getSortedVisibleDatasetMetas().forEach(function(meta) {
 				const index = items[0].index;
-				const element = meta.data[index];
+				const element = getOrCreateElement(meta, index);
 
 				// don't count items that are skipped (null data)
 				if (element && !element.skip) {

src/elements/element.line.js

@@ -24,15 +24,6 @@ defaults._set('elements', {
 	}
 });
 
-function setStyle(ctx, vm) {
-	ctx.lineCap = vm.borderCapStyle;
-	ctx.setLineDash(vm.borderDash);
-	ctx.lineDashOffset = vm.borderDashOffset;
-	ctx.lineJoin = vm.borderJoinStyle;
-	ctx.lineWidth = vm.borderWidth;
-	ctx.strokeStyle = vm.borderColor;
-}
-
 function lineTo(ctx, previous, target) {
 	ctx.lineTo(target.x, target.y);
 }
@@ -324,7 +315,7 @@ class Line extends Element {
 
 		ctx.save();
 
-		setStyle(ctx, me.options);
+		Line._setStyle(ctx, me.options);
 
 		ctx.beginPath();
 
@@ -335,6 +326,15 @@ class Line extends Element {
 		ctx.stroke();
 		ctx.restore();
 	}
+
+	static _setStyle(ctx, options) {
+		ctx.lineCap = options.borderCapStyle;
+		ctx.setLineDash(options.borderDash);
+		ctx.lineDashOffset = options.borderDashOffset;
+		ctx.lineJoin = options.borderJoinStyle;
+		ctx.lineWidth = options.borderWidth;
+		ctx.strokeStyle = options.borderColor;
+	}
 }
 
 Line.prototype._type = 'line';