Vertically align history charts on left axis (#14919)

Co-authored-by: Bram Kragten <mail@bramkragten.nl>
fixes undefined

src/components/chart/ha-chart-base.ts

@@ -10,6 +10,8 @@ import { customElement, property, state } from "lit/decorators";
 import { classMap } from "lit/directives/class-map";
 import { styleMap } from "lit/directives/style-map";
 import { clamp } from "../../common/number/clamp";
+import { computeRTL } from "../../common/util/compute_rtl";
+import { HomeAssistant } from "../../types";
 
 export const MIN_TIME_BETWEEN_UPDATES = 60 * 5 * 1000;
 
@@ -22,6 +24,8 @@ interface Tooltip extends TooltipModel<any> {
 export default class HaChartBase extends LitElement {
   public chart?: Chart;
 
+  @property({ attribute: false }) public hass!: HomeAssistant;
+
   @property({ attribute: "chart-type", reflect: true })
   public chartType: ChartType = "line";
 
@@ -33,6 +37,8 @@ export default class HaChartBase extends LitElement {
 
   @property({ type: Number }) public height?: number;
 
+  @property({ type: Number }) public paddingYAxis = 0;
+
   @state() private _chartHeight?: number;
 
   @state() private _tooltip?: Tooltip;
@@ -128,6 +134,8 @@ export default class HaChartBase extends LitElement {
         style=${styleMap({
           height: `${this.height ?? this._chartHeight}px`,
           overflow: this._chartHeight ? "initial" : "hidden",
+          "padding-left": `${computeRTL(this.hass) ? 0 : this.paddingYAxis}px`,
+          "padding-right": `${computeRTL(this.hass) ? this.paddingYAxis : 0}px`,
         })}
       >
         <canvas></canvas>

src/components/chart/state-history-chart-line.ts

@@ -2,6 +2,8 @@ import type { ChartData, ChartDataset, ChartOptions } from "chart.js";
 import { html, LitElement, PropertyValues } from "lit";
 import { property, state } from "lit/decorators";
 import { getGraphColorByIndex } from "../../common/color/colors";
+import { fireEvent } from "../../common/dom/fire_event";
+import { computeRTL } from "../../common/util/compute_rtl";
 import {
   formatNumber,
   numberFormatToLocale,
@@ -30,17 +32,25 @@ class StateHistoryChartLine extends LitElement {
 
   @property({ attribute: false }) public endTime!: Date;
 
+  @property({ type: Number }) public paddingYAxis = 0;
+
+  @property({ type: Number }) public chartIndex?;
+
   @state() private _chartData?: ChartData<"line">;
 
   @state() private _chartOptions?: ChartOptions;
 
+  @state() private _yWidth = 0;
+
   private _chartTime: Date = new Date();
 
   protected render() {
     return html`
       <ha-chart-base
+        .hass=${this.hass}
         .data=${this._chartData}
         .options=${this._chartOptions}
+        .paddingYAxis=${this.paddingYAxis - this._yWidth}
         chart-type="line"
       ></ha-chart-base>
     `;
@@ -84,6 +94,16 @@ class StateHistoryChartLine extends LitElement {
               display: true,
               text: this.unit,
             },
+            afterUpdate: (y) => {
+              if (this._yWidth !== Math.floor(y.width)) {
+                this._yWidth = Math.floor(y.width);
+                fireEvent(this, "y-width-changed", {
+                  value: this._yWidth,
+                  chartIndex: this.chartIndex,
+                });
+              }
+            },
+            position: computeRTL(this.hass) ? "right" : "left",
           },
         },
         plugins: {

src/components/chart/state-history-chart-timeline.ts

@@ -2,6 +2,7 @@ import type { ChartData, ChartDataset, ChartOptions } from "chart.js";
 import { css, CSSResultGroup, html, LitElement, PropertyValues } from "lit";
 import { customElement, property, state } from "lit/decorators";
 import { formatDateTimeWithSeconds } from "../../common/datetime/format_date_time";
+import { fireEvent } from "../../common/dom/fire_event";
 import { numberFormatToLocale } from "../../common/number/format_number";
 import { computeRTL } from "../../common/util/compute_rtl";
 import { TimelineEntity } from "../../data/history";
@@ -32,18 +33,26 @@ export class StateHistoryChartTimeline extends LitElement {
 
   @property({ attribute: false }) public endTime!: Date;
 
+  @property({ type: Number }) public paddingYAxis = 0;
+
+  @property({ type: Number }) public chartIndex?;
+
   @state() private _chartData?: ChartData<"timeline">;
 
   @state() private _chartOptions?: ChartOptions<"timeline">;
 
+  @state() private _yWidth = 0;
+
   private _chartTime: Date = new Date();
 
   protected render() {
     return html`
       <ha-chart-base
+        .hass=${this.hass}
         .data=${this._chartData}
         .options=${this._chartOptions}
         .height=${this.data.length * 30 + 30}
+        .paddingYAxis=${this.paddingYAxis - this._yWidth}
         chart-type="timeline"
       ></ha-chart-base>
     `;
@@ -131,6 +140,15 @@ export class StateHistoryChartTimeline extends LitElement {
               scaleInstance.width = narrow ? 105 : 185;
             }
           },
+          afterUpdate: (y) => {
+            if (this._yWidth !== Math.floor(y.width)) {
+              this._yWidth = Math.floor(y.width);
+              fireEvent(this, "y-width-changed", {
+                value: this._yWidth,
+                chartIndex: this.chartIndex,
+              });
+            }
+          },
           position: computeRTL(this.hass) ? "right" : "left",
         },
       },

src/components/chart/state-history-charts.ts

@@ -31,6 +31,12 @@ const chunkData = (inputArray: any[], chunks: number) =>
     return results;
   }, []);
 
+declare global {
+  interface HASSDomEvents {
+    "y-width-changed": { value: number; chartIndex: number };
+  }
+}
+
 @customElement("state-history-charts")
 class StateHistoryCharts extends LitElement {
   @property({ attribute: false }) public hass!: HomeAssistant;
@@ -56,6 +62,12 @@ class StateHistoryCharts extends LitElement {
 
   @state() private _computedEndTime!: Date;
 
+  @state() private _maxYWidth = 0;
+
+  @state() private _childYWidths: number[] = [];
+
+  @state() private _chartCount = 0;
+
   // @ts-ignore
   @restoreScroll(".container") private _savedScrollPos?: number;
 
@@ -99,6 +111,8 @@ class StateHistoryCharts extends LitElement {
         ).concat(this.historyData.line)
       : this.historyData.line;
 
+    this._chartCount = combinedItems.length;
+
     return this.virtualize
       ? html`<div class="container ha-scrollbar" @scroll=${this._saveScrollPos}>
           <lit-virtualizer
@@ -130,7 +144,10 @@ class StateHistoryCharts extends LitElement {
           .identifier=${item.identifier}
           .showNames=${this.showNames}
           .endTime=${this._computedEndTime}
+          .paddingYAxis=${this._maxYWidth}
           .names=${this.names}
+          .chartIndex=${index}
+          @y-width-changed=${this._yWidthChanged}
         ></state-history-chart-line>
       </div> `;
     }
@@ -144,6 +161,9 @@ class StateHistoryCharts extends LitElement {
         .names=${this.names}
         .narrow=${this.narrow}
         .chunked=${this.virtualize}
+        .paddingYAxis=${this._maxYWidth}
+        .chartIndex=${index}
+        @y-width-changed=${this._yWidthChanged}
       ></state-history-chart-timeline>
     </div> `;
   };
@@ -152,6 +172,21 @@ class StateHistoryCharts extends LitElement {
     return !(changedProps.size === 1 && changedProps.has("hass"));
   }
 
+  protected updated(changedProps: PropertyValues) {
+    if (changedProps.has("_chartCount")) {
+      if (this._chartCount < this._childYWidths.length) {
+        this._childYWidths.length = this._chartCount;
+        this._maxYWidth =
+          this._childYWidths.length === 0 ? 0 : Math.max(...this._childYWidths);
+      }
+    }
+  }
+
+  private _yWidthChanged(e: CustomEvent<HASSDomEvents["y-width-changed"]>) {
+    this._childYWidths[e.detail.chartIndex] = e.detail.value;
+    this._maxYWidth = Math.max(...this._childYWidths);
+  }
+
   private _isHistoryEmpty(): boolean {
     const historyDataEmpty =
       !this.historyData ||