fastline controller

src/controllers/controller.fastline.js

@@ -0,0 +1,69 @@
+import Line from '../elements/element.line';
+import LineController from './controller.line';
+import defaults from '../core/core.defaults';
+
+defaults.fastline = defaults['line'];
+
+export default class FastLineController extends LineController {
+
+	addElements() {}
+
+	insertElements(start, count) {
+		this.parse(start, count);
+	}
+
+	getMinMax(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() {
+		const me = this;
+		me._cachedMeta._options = me.resolveDatasetElementOptions();
+	}
+
+	draw() {
+		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

@@ -1,6 +1,7 @@
 export {default as bar} from './controller.bar';
 export {default as bubble} from './controller.bubble';
 export {default as doughnut} from './controller.doughnut';
+export {default as fastline} from './controller.fastline';
 export {default as line} from './controller.line';
 export {default as polarArea} from './controller.polarArea';
 export {default as pie} from './controller.pie';

src/core/core.interaction.js

@@ -9,6 +9,16 @@ import {getRelativePosition as helpersGetRelativePosition} from '../helpers/help
  * @typedef {{datasetIndex: number, index: number, element: import("./core.element").default}} InteractionItem
  */
 
+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} e - The event to get the position for
@@ -93,7 +103,7 @@ function optimizedEvaluateItems(chart, axis, position, handler, intersect) {
 		const {index, data} = metasets[i];
 		const {lo, hi} = binarySearch(metasets[i], axis, value, intersect);
 		for (let j = lo; j <= hi; ++j) {
-			const element = data[j];
+			const element = getOrCreateElement(metasets[i], j);
 			if (!element.skip) {
 				handler(element, index, j);
 			}
@@ -213,7 +223,7 @@ export default {
 
 			chart.getSortedVisibleDatasetMetas().forEach((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

@@ -23,15 +23,6 @@ defaults.set(scope, {
 
 defaults.route(scope, ['backgroundColor', 'borderColor'], '', 'color');
 
-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);
 }
@@ -346,7 +337,7 @@ class Line extends Element {
 
 		ctx.save();
 
-		setStyle(ctx, me.options);
+		Line._setStyle(ctx, me.options);
 
 		ctx.beginPath();
 
@@ -359,6 +350,15 @@ class Line extends Element {
 	}
 }
 
+Line._setStyle = function(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;
+};
+
 Line._type = 'line';
 
 export default Line;