Fix splitter (#1307)

Use window for splitter resizing

Signed-off-by: Tilman Vatteroth <git@tilmanvatteroth.de>

src/components/editor-page/editor-page.tsx

@@ -10,7 +10,7 @@ import { useApplyDarkMode } from '../../hooks/common/use-apply-dark-mode'
 import { useDocumentTitleWithNoteTitle } from '../../hooks/common/use-document-title-with-note-title'
 import { useNoteMarkdownContent } from '../../hooks/common/use-note-markdown-content'
 import {
-  SetCheckboxInMarkdownContent,
+  setCheckboxInMarkdownContent,
   setNoteFrontmatter,
   setNoteMarkdownContent,
   updateNoteTitleByFirstHeading
@@ -115,7 +115,7 @@ export const EditorPage: React.FC = () => {
         markdownContent={markdownContent}
         onMakeScrollSource={setRendererToScrollSource}
         onFirstHeadingChange={updateNoteTitleByFirstHeading}
-        onTaskCheckedChange={SetCheckboxInMarkdownContent}
+        onTaskCheckedChange={setCheckboxInMarkdownContent}
         onFrontmatterChange={setNoteFrontmatter}
         onScroll={onMarkdownRendererScroll}
         scrollState={scrollState.rendererScrollState}
@@ -142,7 +142,7 @@ export const EditorPage: React.FC = () => {
               left={leftPane}
               showRight={editorMode === EditorMode.PREVIEW || editorMode === EditorMode.BOTH}
               right={rightPane}
-              containerClassName={'overflow-hidden'}
+              additionalContainerClassName={'overflow-hidden'}
             />
             <Sidebar />
           </div>

src/components/editor-page/splitter/splitter.scss

@@ -6,14 +6,9 @@
 
 .splitter {
   &.left {
-    flex: 0 1 100%;
     min-width: 200px;
   }
 
-  &.right {
-    flex: 1 0 200px;
-  }
-
   &.separator {
     display: flex;
   }

src/components/editor-page/splitter/splitter.tsx

@@ -4,7 +4,7 @@
  * SPDX-License-Identifier: AGPL-3.0-only
  */
 
-import React, { ReactElement, useCallback, useRef, useState } from 'react'
+import React, { ReactElement, useCallback, useEffect, useRef, useState } from 'react'
 import { ShowIf } from '../../common/show-if/show-if'
 import { SplitDivider } from './split-divider/split-divider'
 import './splitter.scss'
@@ -12,70 +12,136 @@ import './splitter.scss'
 export interface SplitterProps {
   left: ReactElement
   right: ReactElement
-  containerClassName?: string
+  additionalContainerClassName?: string
   showLeft: boolean
   showRight: boolean
 }
 
-export const Splitter: React.FC<SplitterProps> = ({ containerClassName, left, right, showLeft, showRight }) => {
-  const [split, setSplit] = useState(50)
-  const realSplit = Math.max(0, Math.min(100, showRight ? split : 100))
-  const [doResizing, setDoResizing] = useState(false)
+/**
+ * Checks if the given {@link Event} is a {@link MouseEvent}
+ * @param event the event to check
+ * @return {@code true} if the given event is a {@link MouseEvent}
+ */
+const isMouseEvent = (event: Event): event is MouseEvent => {
+  return (event as MouseEvent).buttons !== undefined
+}
+
+const isLeftMouseButtonClicked = (mouseEvent: MouseEvent): boolean => {
+  return mouseEvent.buttons === 1
+}
+
+/**
+ * Extracts the absolute horizontal position of the mouse or touch point from the event.
+ * If no position could be found or
+ *
+ * @param moveEvent
+ */
+const extractHorizontalPosition = (moveEvent: MouseEvent | TouchEvent): number => {
+  if (isMouseEvent(moveEvent)) {
+    return moveEvent.pageX
+  } else {
+    return moveEvent.touches[0]?.pageX
+  }
+}
+
+/**
+ * Creates a Left/Right splitter react component.
+ *
+ * @param additionalContainerClassName css classes that are added to the split container.
+ * @param left the react component that should be shown on the left side.
+ * @param right the react component that should be shown on the right side.
+ * @param showLeft defines if the left component should be shown or hidden. Settings this prop will hide the component with css.
+ * @param showRight defines if the right component should be shown or hidden. Settings this prop will hide the component with css.
+ * @return the created component
+ */
+export const Splitter: React.FC<SplitterProps> = ({
+  additionalContainerClassName,
+  left,
+  right,
+  showLeft,
+  showRight
+}) => {
+  const [relativeSplitValue, setRelativeSplitValue] = useState(50)
+  const cappedRelativeSplitValue = Math.max(0, Math.min(100, showRight ? relativeSplitValue : 100))
+  const resizingInProgress = useRef(false)
   const splitContainer = useRef<HTMLDivElement>(null)
 
-  const recalculateSize = (mouseXPosition: number): void => {
-    if (!splitContainer.current) {
-      return
-    }
-    const x = mouseXPosition - splitContainer.current.offsetLeft
-
-    const newSize = x / splitContainer.current.clientWidth
-    setSplit(newSize * 100)
-  }
-
-  const stopResizing = useCallback(() => {
-    setDoResizing(false)
+  /**
+   * Starts the splitter resizing
+   */
+  const onStartResizing = useCallback(() => {
+    resizingInProgress.current = true
   }, [])
 
-  const onMouseMove = useCallback(
-    (mouseEvent: React.MouseEvent<HTMLDivElement, MouseEvent>) => {
-      if (doResizing) {
-        recalculateSize(mouseEvent.pageX)
-        mouseEvent.preventDefault()
+  /**
+   * Stops the splitter resizing
+   */
+  const onStopResizing = useCallback(() => {
+    if (resizingInProgress.current) {
+      resizingInProgress.current = false
     }
-    },
-    [doResizing]
-  )
+  }, [])
 
-  const onTouchMove = useCallback(
-    (touchEvent: React.TouchEvent<HTMLDivElement>) => {
-      if (doResizing) {
-        recalculateSize(touchEvent.touches[0].pageX)
-        touchEvent.preventDefault()
+  /**
+   * Recalculates the panel split based on the absolute mouse/touch position.
+   *
+   * @param moveEvent is a {@link MouseEvent} or {@link TouchEvent} that got triggered.
+   */
+  const onMove = useCallback((moveEvent: MouseEvent | TouchEvent) => {
+    if (!resizingInProgress.current || !splitContainer.current) {
+      return
+    }
+    if (isMouseEvent(moveEvent) && !isLeftMouseButtonClicked(moveEvent)) {
+      resizingInProgress.current = false
+      moveEvent.preventDefault()
+      return undefined
     }
-    },
-    [doResizing]
-  )
 
-  const onGrab = useCallback(() => setDoResizing(true), [])
+    const horizontalPosition = extractHorizontalPosition(moveEvent)
+    const horizontalPositionInSplitContainer = horizontalPosition - splitContainer.current.offsetLeft
+    const newRelativeSize = horizontalPositionInSplitContainer / splitContainer.current.clientWidth
+    setRelativeSplitValue(newRelativeSize * 100)
+    moveEvent.preventDefault()
+  }, [])
+
+  /**
+   * Registers and unregisters necessary event listeners on the body so you can use the split even if the mouse isn't moving over it.
+   */
+  useEffect(() => {
+    const moveHandler = onMove
+    const stopResizeHandler = onStopResizing
+    window.addEventListener('touchmove', moveHandler)
+    window.addEventListener('mousemove', moveHandler)
+    window.addEventListener('touchcancel', stopResizeHandler)
+    window.addEventListener('touchend', stopResizeHandler)
+    window.addEventListener('mouseup', stopResizeHandler)
+
+    return () => {
+      window.removeEventListener('touchmove', moveHandler)
+      window.removeEventListener('mousemove', moveHandler)
+      window.removeEventListener('touchcancel', stopResizeHandler)
+      window.removeEventListener('touchend', stopResizeHandler)
+      window.removeEventListener('mouseup', stopResizeHandler)
+    }
+  }, [resizingInProgress, onMove, onStopResizing])
 
   return (
+    <div ref={splitContainer} className={`flex-fill flex-row d-flex ${additionalContainerClassName || ''}`}>
       <div
-      ref={splitContainer}
-      className={`flex-fill flex-row d-flex ${containerClassName || ''}`}
-      onMouseUp={stopResizing}
-      onTouchEnd={stopResizing}
-      onMouseMove={onMouseMove}
-      onTouchMove={onTouchMove}>
-      <div className={`splitter left ${!showLeft ? 'd-none' : ''}`} style={{ flexBasis: `calc(${realSplit}% - 5px)` }}>
+        className={`splitter left ${!showLeft ? 'd-none' : ''}`}
+        style={{ width: `calc(${cappedRelativeSplitValue}% - 5px)` }}>
         {left}
       </div>
       <ShowIf condition={showLeft && showRight}>
         <div className='splitter separator'>
-          <SplitDivider onGrab={onGrab} />
+          <SplitDivider onGrab={onStartResizing} />
         </div>
       </ShowIf>
-      <div className={`splitter right ${!showRight ? 'd-none' : ''}`}>{right}</div>
+      <div
+        className={`splitter right ${!showRight ? 'd-none' : ''}`}
+        style={{ width: `calc(100% - ${cappedRelativeSplitValue}%)` }}>
+        {right}
+      </div>
     </div>
   )
 }

src/components/markdown-renderer/markdown-renderer.scss

@@ -11,6 +11,17 @@
   font-family: 'Source Sans Pro', "Twemoji", sans-serif;
   word-break: break-word;
 
+  .svg-container {
+    overflow-x: auto;
+    width: 100%;
+    display: inline-block;
+    text-align: center;
+
+    svg {
+      max-width: 100%;
+    }
+  }
+
   .alert > p, .alert > ul {
     margin-bottom: 0;
   }

src/components/markdown-renderer/replace-components/abc/abc-frame.tsx

@@ -28,5 +28,5 @@ export const AbcFrame: React.FC<AbcFrameProps> = ({ code }) => {
       })
   }, [code])
 
-  return <div ref={container} className={'abcjs-score bg-white text-black text-center overflow-x-auto'} />
+  return <div ref={container} className={'abcjs-score bg-white text-black svg-container'} />
 }

src/components/markdown-renderer/replace-components/graphviz/graphviz-frame.tsx

@@ -63,7 +63,7 @@ export const GraphvizFrame: React.FC<GraphvizFrameProps> = ({ code }) => {
       <ShowIf condition={!!error}>
         <Alert variant={'warning'}>{error}</Alert>
       </ShowIf>
-      <div className={'text-center overflow-x-auto'} data-cy={'graphviz'} ref={container} />
+      <div className={'svg-container'} data-cy={'graphviz'} ref={container} />
     </Fragment>
   )
 }

src/components/markdown-renderer/replace-components/markmap/markmap-frame.tsx

@@ -64,7 +64,7 @@ export const MarkmapFrame: React.FC<MarkmapFrameProps> = ({ code }) => {
 
   return (
     <div data-cy={'markmap'}>
-      <div className={'text-center'} ref={diagramContainer} />
+      <div className={'svg-container'} ref={diagramContainer} />
       <div className={'text-right button-inside'}>
         <LockButton
           locked={disablePanAndZoom}

src/redux/note-details/methods.ts

@@ -48,7 +48,7 @@ export const setNoteFrontmatter = (frontmatter: NoteFrontmatter | undefined): vo
   } as SetNoteFrontmatterFromRenderingAction)
 }
 
-export const SetCheckboxInMarkdownContent = (lineInMarkdown: number, checked: boolean): void => {
+export const setCheckboxInMarkdownContent = (lineInMarkdown: number, checked: boolean): void => {
   store.dispatch({
     type: NoteDetailsActionType.SET_CHECKBOX_IN_MARKDOWN_CONTENT,
     checked: checked,