From c6c4d2ca64ccf86ee3d3dee0c4d758604da89439 Mon Sep 17 00:00:00 2001
From: Luca Falasco <falasco.luca@gmail.com>
Date: Tue, 11 Feb 2020 16:26:39 +0100
Subject: [PATCH] add ruler and axis tooltip

---
 packages/core/src/components/axes/grid.ts     | 71 ++++++++++++++++++-
 packages/core/src/configuration.ts            |  4 +-
 .../core/src/styles/components/_grid.scss     | 13 ++++
 3 files changed, 85 insertions(+), 3 deletions(-)

diff --git a/packages/core/src/components/axes/grid.ts b/packages/core/src/components/axes/grid.ts
index 824684e704..45310caa5e 100644
--- a/packages/core/src/components/axes/grid.ts
+++ b/packages/core/src/components/axes/grid.ts
@@ -5,7 +5,7 @@ import { DOMUtils } from "../../services";
 
 // D3 Imports
 import { axisBottom, axisLeft } from "d3-axis";
-import { mouse, select } from "d3-selection";
+import { mouse, select, event } from "d3-selection";
 import { TooltipTypes } from "../../interfaces";
 
 export class Grid extends Component {
@@ -140,6 +140,71 @@ export class Grid extends Component {
 		return gridlinesX;
 	}
 
+	showRuler([x, y]: [number, number]) {
+		const height = Number(this.backdrop.attr("height"));
+		const svg = this.parent;
+		const line = DOMUtils.appendOrSelect(svg, "line.ruler");
+
+		const data = Array.prototype.concat(
+			...this.model.getData().datasets.map(dataset => dataset.data.map(d => d.date))
+		);
+		const scale = this.services.cartesianScales.getMainXScale();
+		const dataPoints = data.map(d => Number(scale(d)));
+
+		const values = dataPoints.filter(d => d > x - 3 && d < x + 3);
+		const highlightItems = values.map(v =>
+			this.services.cartesianScales.getDataFromDomain(scale.invert(v))
+		)[0];
+
+		if (highlightItems && highlightItems.length > 0) {
+			this.services.events.dispatchEvent("show-tooltip", {
+				hoveredElement: line,
+				multidata: highlightItems,
+				type: TooltipTypes.GRIDLINE
+			});
+		}
+		line.attr("y1", 0)
+			.attr("y2", height)
+			.attr("x1", x)
+			.attr("x2", x);
+
+		// if scale can't be inverted don't show axis tooltip
+		if (!scale.invert) {
+			return;
+		}
+
+		// append axis tooltip
+		const axisTooltipValue = `${scale.invert(x)}`.substring(0, 10);
+		const axisTooltip = DOMUtils.appendOrSelect(svg, "g.axis-tooltip").attr("opacity", 1);
+		const axisTooltipWidth = 70;
+		const axisTooltipHeight = 20;
+		const axisTooltipOffset = 5;
+
+		DOMUtils.appendOrSelect(axisTooltip, "rect.axis-tooltip-box")
+			.attr("x", x - axisTooltipWidth / 2)
+			.attr("y", height + axisTooltipOffset)
+			.attr("width", axisTooltipWidth)
+			.attr("height", axisTooltipHeight);
+
+		DOMUtils.appendOrSelect(axisTooltip, "text.axis-tooltip-text")
+			.attr("x", x)
+			.attr("y", height + axisTooltipOffset + axisTooltipHeight / 2)
+			.text(axisTooltipValue);
+	}
+
+	hideRuler() {
+		const svg = this.parent;
+		const line = DOMUtils.appendOrSelect(svg, "line.ruler");
+		const axisTooltip = DOMUtils.appendOrSelect(svg, "g.axis-tooltip");
+
+		line.attr("y1", null)
+			.attr("y2", null)
+			.attr("x1", null)
+			.attr("x2", null);
+
+		axisTooltip.attr("opacity", 0);
+	}
+
 	/**
 	 * Adds the listener on the X grid to trigger multiple point tooltips along the x axis.
 	 */
@@ -161,9 +226,12 @@ export class Grid extends Component {
 			const activeGridline = self.getActiveGridline(pos);
 			if (activeGridline.empty()) {
 				self.services.events.dispatchEvent("hide-tooltip", {});
+				self.showRuler(pos);
 				return;
 			}
 
+			self.hideRuler();
+
 			// set active class to control dasharray and theme colors
 			activeGridline
 			.classed("active", true);
@@ -186,6 +254,7 @@ export class Grid extends Component {
 			svg.selectAll(".x.grid .tick")
 			.classed("active", false);
 
+			self.hideRuler();
 			self.services.events.dispatchEvent("hide-tooltip", {});
 		});
 	}
diff --git a/packages/core/src/configuration.ts b/packages/core/src/configuration.ts
index b0e388e02a..d7e6ebae2d 100644
--- a/packages/core/src/configuration.ts
+++ b/packages/core/src/configuration.ts
@@ -79,8 +79,8 @@ export const baseTooltip: TooltipOptions = {
 export const axisChartTooltip: AxisTooltipOptions = Tools.merge({}, baseTooltip, {
 	gridline: {
 		enabled: true,
-		threshold: 0.25
-	}
+		threshold: 0.15
+	},
 } as AxisTooltipOptions);
 
 export const barChartTooltip: BarTooltipOptions = Tools.merge({}, axisChartTooltip , {
diff --git a/packages/core/src/styles/components/_grid.scss b/packages/core/src/styles/components/_grid.scss
index 0a9993ec3d..11bbc81ecc 100644
--- a/packages/core/src/styles/components/_grid.scss
+++ b/packages/core/src/styles/components/_grid.scss
@@ -1,4 +1,17 @@
 .#{$prefix}--#{$charts-prefix}--grid {
+	line.ruler {
+		stroke: #009bef;
+		stroke-width: 1px;
+		stroke-dasharray: 2;
+		pointer-events: none;
+	}
+
+	text.axis-tooltip-text {
+		fill: white;
+		alignment-baseline: middle;
+		text-anchor: middle;
+	}
+
 	rect.chart-grid-backdrop {
 		@if $carbon--theme == $carbon--theme--g10 {
 			fill: $ui-01;