From 32ed3e8009761cba74e36177a71077d22f567426 Mon Sep 17 00:00:00 2001
From: Leon Sorokin <leeoniya@gmail.com>
Date: Tue, 26 Sep 2023 18:12:45 -0500
Subject: [PATCH] TimeSeries: Implement ad hoc y-zoom via Shift-drag (#75408)

---
 .../components/uPlot/plugins/ZoomPlugin.tsx   | 91 ++++++++++++++-----
 .../panel/candlestick/CandlestickPanel.tsx    |  2 +-
 .../panel/timeseries/TimeSeriesPanel.tsx      |  2 +-
 3 files changed, 70 insertions(+), 25 deletions(-)

diff --git a/packages/grafana-ui/src/components/uPlot/plugins/ZoomPlugin.tsx b/packages/grafana-ui/src/components/uPlot/plugins/ZoomPlugin.tsx
index d0697334379..415d000d303 100644
--- a/packages/grafana-ui/src/components/uPlot/plugins/ZoomPlugin.tsx
+++ b/packages/grafana-ui/src/components/uPlot/plugins/ZoomPlugin.tsx
@@ -1,10 +1,10 @@
 import { useLayoutEffect } from 'react';
 
 import { UPlotConfigBuilder } from '../config/UPlotConfigBuilder';
-import { pluginLog } from '../utils';
 
 interface ZoomPluginProps {
   onZoom: (range: { from: number; to: number }) => void;
+  withZoomY?: boolean;
   config: UPlotConfigBuilder;
 }
 
@@ -14,41 +14,86 @@ const MIN_ZOOM_DIST = 5;
 /**
  * @alpha
  */
-export const ZoomPlugin = ({ onZoom, config }: ZoomPluginProps) => {
+export const ZoomPlugin = ({ onZoom, config, withZoomY = false }: ZoomPluginProps) => {
   useLayoutEffect(() => {
-    config.addHook('setSelect', (u) => {
-      const min = u.posToVal(u.select.left, 'x');
-      const max = u.posToVal(u.select.left + u.select.width, 'x');
+    let yZoomed = false;
+    let yDrag = false;
 
-      if (u.select.width >= MIN_ZOOM_DIST) {
-        pluginLog('ZoomPlugin', false, 'selected', {
-          min,
-          max,
-          bbox: {
-            left: u.bbox.left / window.devicePixelRatio + u.select.left,
-            top: u.bbox.top / window.devicePixelRatio,
-            height: u.bbox.height / window.devicePixelRatio,
-            width: u.select.width,
+    if (withZoomY) {
+      config.addHook('init', (u) => {
+        u.root!.addEventListener(
+          'mousedown',
+          (e) => {
+            if (e.button === 0 && e.shiftKey) {
+              yDrag = true;
+
+              u.cursor!.drag!.x = false;
+              u.cursor!.drag!.y = true;
+
+              let onUp = (e: MouseEvent) => {
+                u.cursor!.drag!.x = true;
+                u.cursor!.drag!.y = false;
+                document.removeEventListener('mouseup', onUp, true);
+              };
+
+              document.addEventListener('mouseup', onUp, true);
+            }
           },
-        });
-        onZoom({ from: min, to: max });
+          true
+        );
+      });
+    }
+
+    config.addHook('setSelect', (u) => {
+      if (withZoomY && yDrag) {
+        if (u.select.height >= MIN_ZOOM_DIST) {
+          for (let key in u.scales!) {
+            if (key !== 'x') {
+              const maxY = u.posToVal(u.select.top, key);
+              const minY = u.posToVal(u.select.top + u.select.height, key);
+
+              u.setScale(key, { min: minY, max: maxY });
+            }
+          }
+
+          yZoomed = true;
+        }
+
+        yDrag = false;
+      } else {
+        if (u.select.width >= MIN_ZOOM_DIST) {
+          const minX = u.posToVal(u.select.left, 'x');
+          const maxX = u.posToVal(u.select.left + u.select.width, 'x');
+
+          onZoom({ from: minX, to: maxX });
+        }
       }
 
       // manually hide selected region (since cursor.drag.setScale = false)
-      /* @ts-ignore */
-      u.setSelect({ left: 0, width: 0 }, false);
+      u.setSelect({ left: 0, width: 0, top: 0, height: 0 }, false);
     });
 
     config.setCursor({
       bind: {
         dblclick: (u) => () => {
-          let xScale = u.scales.x;
+          if (withZoomY && yZoomed) {
+            for (let key in u.scales!) {
+              if (key !== 'x') {
+                // @ts-ignore (this is not typed correctly in uPlot, assigning nulls means auto-scale / reset)
+                u.setScale(key, { min: null, max: null });
+              }
+            }
 
-          const frTs = xScale.min!;
-          const toTs = xScale.max!;
-          const pad = (toTs - frTs) / 2;
+            yZoomed = false;
+          } else {
+            let xScale = u.scales.x;
 
-          onZoom({ from: frTs - pad, to: toTs + pad });
+            const frTs = xScale.min!;
+            const toTs = xScale.max!;
+            const pad = (toTs - frTs) / 2;
+
+            onZoom({ from: frTs - pad, to: toTs + pad });
+          }
 
           return null;
         },
diff --git a/public/app/plugins/panel/candlestick/CandlestickPanel.tsx b/public/app/plugins/panel/candlestick/CandlestickPanel.tsx
index 2611c40d823..e0707a3820f 100644
--- a/public/app/plugins/panel/candlestick/CandlestickPanel.tsx
+++ b/public/app/plugins/panel/candlestick/CandlestickPanel.tsx
@@ -254,7 +254,7 @@ export const CandlestickPanel = ({
 
         return (
           <>
-            <ZoomPlugin config={config} onZoom={onChangeTimeRange} />
+            <ZoomPlugin config={config} onZoom={onChangeTimeRange} withZoomY={true} />
             <TooltipPlugin
               data={alignedDataFrame}
               config={config}
diff --git a/public/app/plugins/panel/timeseries/TimeSeriesPanel.tsx b/public/app/plugins/panel/timeseries/TimeSeriesPanel.tsx
index f77aba6abcb..752fc49ba3f 100644
--- a/public/app/plugins/panel/timeseries/TimeSeriesPanel.tsx
+++ b/public/app/plugins/panel/timeseries/TimeSeriesPanel.tsx
@@ -87,7 +87,7 @@ export const TimeSeriesPanel = ({
         return (
           <>
             <KeyboardPlugin config={config} />
-            <ZoomPlugin config={config} onZoom={onChangeTimeRange} />
+            <ZoomPlugin config={config} onZoom={onChangeTimeRange} withZoomY={true} />
             {options.tooltip.mode === TooltipDisplayMode.None || (
               <TooltipPlugin
                 frames={frames}