Add zoom & pan to charts

package.json

@@ -102,6 +102,7 @@
     "app-datepicker": "5.1.1",
     "barcode-detector": "2.3.1",
     "chart.js": "4.4.7",
+    "chartjs-plugin-zoom": "2.2.0",
     "color-name": "2.0.0",
     "comlink": "4.4.2",
     "core-js": "3.39.0",

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

@@ -14,6 +14,7 @@ import { fireEvent } from "../../common/dom/fire_event";
 import { clamp } from "../../common/number/clamp";
 import type { HomeAssistant } from "../../types";
 import { debounce } from "../../common/util/debounce";
+import { isMac } from "../../util/is_mac";
 
 export const MIN_TIME_BETWEEN_UPDATES = 60 * 5 * 1000;
 
@@ -64,6 +65,8 @@ export class HaChartBase extends LitElement {
 
   @state() private _hiddenDatasets: Set<number> = new Set();
 
+  @state() private _showZoomHint = false;
+
   private _paddingUpdateCount = 0;
 
   private _paddingUpdateLock = false;
@@ -201,7 +204,9 @@ export class HaChartBase extends LitElement {
       }
       this.chart.data = this.data;
     }
-    if (changedProps.has("options")) {
+    if (changedProps.has("options") && !this.chart.isZoomedOrPanned()) {
+      // this resets the chart zoom because min/max scales changed
+      // so we only do it if the user is not zooming or panning
       this.chart.options = this._createOptions();
     }
     this.chart.update("none");
@@ -249,7 +254,7 @@ export class HaChartBase extends LitElement {
         })}
       >
         <div
-          class="chartContainer"
+          class="chart-container"
           style=${styleMap({
             height: `${
               this.height ?? this._chartHeight ?? this.clientWidth / 2
@@ -259,8 +264,22 @@ export class HaChartBase extends LitElement {
             "padding-inline-start": `${this._paddingYAxisInternal}px`,
             "padding-inline-end": 0,
           })}
+          @wheel=${this._handleChartScroll}
         >
           <canvas></canvas>
+          <div
+            class="zoom-hint ${classMap({
+              visible: this._showZoomHint,
+            })}"
+          >
+            <div>
+              ${isMac
+                ? this.hass.localize(
+                    "ui.components.history_charts.zoom_hint_mac"
+                  )
+                : this.hass.localize("ui.components.history_charts.zoom_hint")}
+            </div>
+          </div>
           ${this._tooltip
             ? html`<div
                 class="chartTooltip ${classMap({
@@ -343,7 +362,8 @@ export class HaChartBase extends LitElement {
     }
   }
 
-  private _createOptions() {
+  private _createOptions(): ChartOptions {
+    const modifierKey = isMac ? "meta" : "ctrl";
     return {
       maintainAspectRatio: false,
       ...this.options,
@@ -358,6 +378,36 @@ export class HaChartBase extends LitElement {
           ...this.options?.plugins?.legend,
           display: false,
         },
+        zoom: {
+          ...this.options?.plugins?.zoom,
+          pan: {
+            enabled: true,
+          },
+          zoom: {
+            pinch: {
+              enabled: true,
+            },
+            drag: {
+              enabled: true,
+              modifierKey,
+            },
+            wheel: {
+              enabled: true,
+              modifierKey,
+            },
+            mode: "x",
+          },
+          limits: {
+            x: {
+              min: "original",
+              max: "original",
+            },
+            y: {
+              min: "original",
+              max: "original",
+            },
+          },
+        },
       },
     };
   }
@@ -382,6 +432,16 @@ export class HaChartBase extends LitElement {
     ];
   }
 
+  private _handleChartScroll(ev: MouseEvent) {
+    const modifier = isMac ? "metaKey" : "ctrlKey";
+    if (!ev[modifier] && !this._showZoomHint) {
+      this._showZoomHint = true;
+      setTimeout(() => {
+        this._showZoomHint = false;
+      }, 1000);
+    }
+  }
+
   private _legendClick(ev) {
     if (!this.chart) {
       return;
@@ -450,6 +510,9 @@ export class HaChartBase extends LitElement {
         height: 0;
         transition: height 300ms cubic-bezier(0.4, 0, 0.2, 1);
       }
+      .chart-container {
+        position: relative;
+      }
       canvas {
         max-height: var(--chart-max-height, 400px);
       }
@@ -539,6 +602,31 @@ export class HaChartBase extends LitElement {
         font-weight: 300;
         word-break: break-all;
       }
+      .zoom-hint {
+        position: absolute;
+        top: 0;
+        left: 0;
+        right: 0;
+        bottom: 0;
+        display: flex;
+        align-items: center;
+        justify-content: center;
+        opacity: 0;
+        transition: opacity 500ms cubic-bezier(0.4, 0, 0.2, 1);
+        pointer-events: none;
+      }
+      .zoom-hint.visible {
+        opacity: 1;
+      }
+      .zoom-hint > div {
+        color: white;
+        font-size: 1.5em;
+        font-weight: 500;
+        padding: 8px;
+        border-radius: 8px;
+        background: rgba(0, 0, 0, 0.3);
+        box-shadow: 0 0 32px 32px rgba(0, 0, 0, 0.3);
+      }
     `;
   }
 }

src/resources/chartjs.ts

@@ -1,3 +1,4 @@
+import ZoomPlugin from "chartjs-plugin-zoom";
 import {
   LineController,
   TimeScale,
@@ -35,5 +36,6 @@ Chart.register(
   TextBarElement,
   TimelineController,
   CategoryScale,
-  LogarithmicScale
+  LogarithmicScale,
+  ZoomPlugin
 );

src/translations/en.json

@@ -828,7 +828,9 @@
         "error": "Unable to load history",
         "duration": "Duration",
         "source_history": "Source: History",
-        "source_stats": "Source: Long term statistics"
+        "source_stats": "Source: Long term statistics",
+        "zoom_hint": "Use ctrl + scroll to zoom in/out",
+        "zoom_hint_mac": "Use ⌘ + scroll to zoom in/out"
       },
       "map": {
         "error": "Unable to load map"

src/util/is_mac.ts

@@ -0,0 +1 @@
+export const isMac = /Mac/i.test(navigator.userAgent);

yarn.lock

@@ -4585,10 +4585,10 @@ __metadata:
   languageName: node
   linkType: hard
 
-"@types/hammerjs@npm:^2.0.36":
-  version: 2.0.45
-  resolution: "@types/hammerjs@npm:2.0.45"
-  checksum: 10/8d7f8791789853a9461f6445e625f18922a823a61042161dde5513f4a2c15ecd6361fa6f9b457ce13bfb6b518489b892fedb9e2cebb4420523cb45f1cbb4ee88
+"@types/hammerjs@npm:^2.0.36, @types/hammerjs@npm:^2.0.45":
+  version: 2.0.46
+  resolution: "@types/hammerjs@npm:2.0.46"
+  checksum: 10/1b6502d668f45ca49fb488c01f7938d3aa75e989d70c64801c8feded7d659ca1a118f745c1b604d220efe344c93231767d5cc68c05e00e069c14539b6143cfd9
   languageName: node
   linkType: hard
 
@@ -6417,6 +6417,18 @@ __metadata:
   languageName: node
   linkType: hard
 
+"chartjs-plugin-zoom@npm:2.2.0":
+  version: 2.2.0
+  resolution: "chartjs-plugin-zoom@npm:2.2.0"
+  dependencies:
+    "@types/hammerjs": "npm:^2.0.45"
+    hammerjs: "npm:^2.0.8"
+  peerDependencies:
+    chart.js: ">=3.2.0"
+  checksum: 10/4a549b1b21ed5433f9ba67038d6176ed545b2881521e12d6b8024cd2ab08fb008c36fe388ab2ac7ee2ac334bf44a8d785703570388fa0e0b4c22c18602536f9c
+  languageName: node
+  linkType: hard
+
 "check-error@npm:^2.1.1":
   version: 2.1.1
   resolution: "check-error@npm:2.1.1"
@@ -9019,6 +9031,13 @@ __metadata:
   languageName: node
   linkType: hard
 
+"hammerjs@npm:^2.0.8":
+  version: 2.0.8
+  resolution: "hammerjs@npm:2.0.8"
+  checksum: 10/9155d056f252ef35e8ca258dbb5ee2c9d8794f6805d083da7d1d9763d185e3e149459ecc2b36ccce584e3cd5f099fd9fa55056e3bcc7724046390f2e5ae25815
+  languageName: node
+  linkType: hard
+
 "handle-thing@npm:^2.0.0":
   version: 2.0.1
   resolution: "handle-thing@npm:2.0.1"
@@ -9229,6 +9248,7 @@ __metadata:
     barcode-detector: "npm:2.3.1"
     browserslist-useragent-regexp: "npm:4.1.3"
     chart.js: "npm:4.4.7"
+    chartjs-plugin-zoom: "npm:2.2.0"
     color-name: "npm:2.0.0"
     comlink: "npm:4.4.2"
     core-js: "npm:3.39.0"