fix(files): Correctly scroll selected file into view

Signed-off-by: Ferdinand Thiessen <[email protected]>

apps/files/src/components/FilesListTableFooter.vue

@@ -141,7 +141,7 @@ export default defineComponent({
 <style scoped lang="scss">
 // Scoped row
 tr {
-	margin-bottom: max(25vh, var(--body-container-margin));
+	margin-bottom: var(--body-container-margin);
 	border-top: 1px solid var(--color-border);
 	// Prevent hover effect on the whole row
 	background-color: transparent !important;

apps/files/src/components/FilesListVirtual.vue

@@ -536,7 +536,6 @@ export default defineComponent({
 			flex-direction: column;
 			width: 100%;
 			background-color: var(--color-main-background);
-
 		}
 
 		// Table header
@@ -853,8 +852,7 @@ export default defineComponent({
 
 <style lang="scss">
 // Grid mode
-tbody.files-list__tbody.files-list__tbody--grid {
-	--half-clickable-area: calc(var(--clickable-area) / 2);
+.files-list--grid tbody.files-list__tbody {
 	--item-padding: 16px;
 	--icon-preview-size: 166px;
 	--name-height: 32px;
@@ -945,7 +943,7 @@ tbody.files-list__tbody.files-list__tbody--grid {
 
 	.files-list__row-actions {
 		position: absolute;
-		inset-inline-end: calc(var(--half-clickable-area) / 2);
+		inset-inline-end: calc(var(--clickable-area) / 4);
 		inset-block-end: calc(var(--mtime-height) / 2);
 		width: var(--clickable-area);
 		height: var(--clickable-area);

apps/files/src/components/VirtualList.vue

@@ -3,13 +3,16 @@
  - SPDX-License-Identifier: AGPL-3.0-or-later
  -->
 <template>
-	<div class="files-list" data-cy-files-list>
+	<div class="files-list"
+		:class="{ 'files-list--grid': gridMode }"
+		data-cy-files-list
+		@scroll.passive="onScroll">
 		<!-- Header -->
 		<div ref="before" class="files-list__before">
 			<slot name="before" />
 		</div>
 
-		<div class="files-list__filters">
+		<div ref="filters" class="files-list__filters">
 			<slot name="filters" />
 		</div>
 
@@ -31,7 +34,6 @@
 			<!-- Body -->
 			<tbody :style="tbodyStyle"
 				class="files-list__tbody"
-				:class="gridMode ? 'files-list__tbody--grid' : 'files-list__tbody--list'"
 				data-cy-files-list-tbody>
 				<component :is="dataComponent"
 					v-for="({key, item}, i) in renderedItems"
@@ -42,7 +44,7 @@
 			</tbody>
 
 			<!-- Footer -->
-			<tfoot v-show="isReady"
+			<tfoot ref="footer"
 				class="files-list__tfoot"
 				data-cy-files-list-tfoot>
 				<slot name="footer" />
@@ -118,6 +120,7 @@ export default defineComponent({
 		return {
 			index: this.scrollToIndex,
 			beforeHeight: 0,
+			footerHeight: 0,
 			headerHeight: 0,
 			tableHeight: 0,
 			resizeObserver: null as ResizeObserver | null,
@@ -145,16 +148,33 @@ export default defineComponent({
 			// 166px + 32px (name) + 16px (mtime) + 16px (padding top and bottom)
 			return this.gridMode ? (166 + 32 + 16 + 16 + 16) : 55
 		},
+
 		// Grid mode only
 		itemWidth() {
 			// 166px + 16px x 2 (padding left and right)
 			return 166 + 16 + 16
 		},
 
-		rowCount() {
-			return Math.ceil((this.tableHeight - this.headerHeight) / this.itemHeight) + (this.bufferItems / this.columnCount) * 2 + 1
+		/**
+		 * The number of rows currently (fully!) visible
+		 */
+		visibleRows(): number {
+			return Math.floor((this.tableHeight - this.headerHeight) / this.itemHeight)
+		},
+
+		/**
+		 * Number of rows that will be rendered.
+		 * This includes only visible + buffer rows.
+		 */
+		rowCount(): number {
+			return this.visibleRows + (this.bufferItems / this.columnCount) * 2 + 1
 		},
-		columnCount() {
+
+		/**
+		 * Number of columns.
+		 * 1 for list view otherwise depending on the file list width.
+		 */
+		columnCount(): number {
 			if (!this.gridMode) {
 				return 1
 			}
@@ -217,16 +237,18 @@ export default defineComponent({
 		 * The total number of rows that are available
 		 */
 		totalRowCount() {
-			return Math.floor(this.dataSources.length / this.columnCount)
+			return Math.ceil(this.dataSources.length / this.columnCount)
 		},
 
 		tbodyStyle() {
-			const isOverScrolled = this.startIndex + this.rowCount > this.dataSources.length
-			const lastIndex = this.dataSources.length - this.startIndex - this.shownItems
-			const hiddenAfterItems = Math.floor(Math.min(this.dataSources.length - this.startIndex, lastIndex) / this.columnCount)
+			// The number of (virtual) rows above the currently rendered ones.
+			// start index is aligned so this should always be an integer
+			const rowsAbove = Math.round(this.startIndex / this.columnCount)
+			// The number of (virtual) rows below the currently rendered ones.
+			const rowsBelow = Math.max(0, this.totalRowCount - rowsAbove - this.rowCount)
+
 			return {
-				paddingTop: `${Math.floor(this.startIndex / this.columnCount) * this.itemHeight}px`,
-				paddingBottom: isOverScrolled ? 0 : `${hiddenAfterItems * this.itemHeight}px`,
+				paddingBlock: `${rowsAbove * this.itemHeight}px ${rowsBelow * this.itemHeight}px`,
 				minHeight: `${this.totalRowCount * this.itemHeight}px`,
 			}
 		},
@@ -238,15 +260,14 @@ export default defineComponent({
 
 		totalRowCount() {
 			if (this.scrollToIndex) {
-				this.$nextTick(() => this.scrollTo(this.scrollToIndex))
+				this.scrollTo(this.scrollToIndex)
 			}
 		},
 
 		columnCount(columnCount, oldColumnCount) {
 			if (oldColumnCount === 0) {
-				// We're initializing, the scroll position
-				// is handled on mounted
-				console.debug('VirtualList: columnCount is 0, skipping scroll')
+				// We're initializing, the scroll position is handled on mounted
+				logger.debug('VirtualList: columnCount is 0, skipping scroll')
 				return
 			}
 			// If the column count changes in grid view,
@@ -256,30 +277,28 @@ export default defineComponent({
 	},
 
 	mounted() {
-		const before = this.$refs?.before as HTMLElement
-		const root = this.$el as HTMLElement
-		const thead = this.$refs?.thead as HTMLElement
+		this.$_recycledPool = {} as Record<string, DataSource[DataSourceKey]>
 
 		this.resizeObserver = new ResizeObserver(debounce(() => {
-			this.beforeHeight = before?.clientHeight ?? 0
-			this.headerHeight = thead?.clientHeight ?? 0
-			this.tableHeight = root?.clientHeight ?? 0
+			this.updateHeightVariables()
 			logger.debug('VirtualList: resizeObserver updated')
 			this.onScroll()
-		}, 100, { immediate: false }))
-
-		this.resizeObserver.observe(before)
-		this.resizeObserver.observe(root)
-		this.resizeObserver.observe(thead)
-
-		if (this.scrollToIndex) {
-			this.scrollTo(this.scrollToIndex)
-		}
-
-		// Adding scroll listener AFTER the initial scroll to index
-		this.$el.addEventListener('scroll', this.onScroll, { passive: true })
-
-		this.$_recycledPool = {} as Record<string, DataSource[DataSourceKey]>
+		}, 100))
+		this.resizeObserver.observe(this.$el)
+		this.resizeObserver.observe(this.$refs.before as HTMLElement)
+		this.resizeObserver.observe(this.$refs.filters as HTMLElement)
+		this.resizeObserver.observe(this.$refs.footer as HTMLElement)
+
+		this.$nextTick(() => {
+			// Make sure height values are initialized
+			this.updateHeightVariables()
+			// If we need to scroll to an index we do so in the next tick.
+			// This is needed to apply updates from the initialization of the height variables
+			// which will update the tbody styles until next tick.
+			if (this.scrollToIndex) {
+				this.scrollTo(this.scrollToIndex)
+			}
+		})
 	},
 
 	beforeDestroy() {
@@ -294,17 +313,56 @@ export default defineComponent({
 				return
 			}
 
-			// Check if the content is smaller than the viewport, meaning no scrollbar
-			const targetRow = Math.ceil(this.dataSources.length / this.columnCount)
-			if (targetRow < this.rowCount) {
-				logger.debug('VirtualList: Skip scrolling, nothing to scroll', { index, targetRow, rowCount: this.rowCount })
+			// Check if the content is smaller (not equal! keep the footer in mind) than the viewport
+			// meaning there is no scrollbar
+			if (this.totalRowCount < this.visibleRows) {
+				logger.debug('VirtualList: Skip scrolling, nothing to scroll', {
+					index,
+					totalRows: this.totalRowCount,
+					visibleRows: this.visibleRows,
+				})
 				return
 			}
 
-			// Scroll to one row and a half before the index
-			const scrollTop = this.indexToScrollPos(index)
-			logger.debug('VirtualList: scrolling to index ' + index, { scrollTop, columnCount: this.columnCount, beforeHeight: this.beforeHeight })
-			this.$el.scrollTop = scrollTop
+			// We can not scroll further as the last page of rows
+			// For the grid view we also need to account for all columns in that row (columnCount - 1)
+			const clampedIndex = (this.totalRowCount - this.visibleRows) * this.columnCount + (this.columnCount - 1)
+			// The scroll position
+			let scrollTop = this.indexToScrollPos(Math.min(index, clampedIndex))
+
+			// First we need to update the internal index for rendering.
+			// This will cause the <tbody> element to be resized allowing us to set the correct scroll position.
+			this.index = index
+
+			// If this is not the first row we can add a half row from above.
+			// This is to help users understand the table is scrolled and not items did not just disappear.
+			// But we also can only add a half row if we have enough rows below to scroll (visual rows / end of scrollable area)
+			if (index >= this.columnCount && index <= clampedIndex) {
+				scrollTop -= (this.itemHeight / 2)
+				// As we render one half row more we also need to adjust the internal index
+				this.index = index - this.columnCount
+			} else if (index > clampedIndex) {
+				// If we are on the last page we cannot scroll any further
+				// but we can at least scroll the footer into view
+				if (index <= (clampedIndex + this.columnCount)) {
+					// We only show have of the footer for the first of the last page
+					// To still show the previous row partly. Same reasoning as above:
+					// help the user understand that the table is scrolled not "magically trimmed"
+					scrollTop += this.footerHeight / 2
+				} else {
+					// We reached the very end of the files list and we are focussing not the first visible row
+					// so all we now can do is scroll to the end (footer)
+					scrollTop += this.footerHeight
+				}
+			}
+
+			// Now we need to wait for the <tbody> element to get resized so we can correctly apply the scrollTop position
+			this.$nextTick(() => {
+				this.$el.scrollTop = scrollTop
+				logger.debug(`VirtualList: scrolling to index ${index}`, {
+					clampedIndex, scrollTop, columnCount: this.columnCount, total: this.totalRowCount, visibleRows: this.visibleRows, beforeHeight: this.beforeHeight,
+				})
+			})
 		},
 
 		onScroll() {
@@ -333,7 +391,22 @@ export default defineComponent({
 		// Convert index to scroll position
 		// It should be the opposite of `scrollPosToIndex`
 		indexToScrollPos(index: number): number {
-			return (Math.floor(index / this.columnCount) - 0.5) * this.itemHeight + this.beforeHeight
+			return Math.floor(index / this.columnCount) * this.itemHeight + this.beforeHeight
+		},
+
+		/**
+		 * Update the height variables.
+		 * To be called by resize observer and `onMount`
+		 */
+		updateHeightVariables(): void {
+			this.tableHeight = this.$el?.clientHeight ?? 0
+			this.beforeHeight = (this.$refs.before as HTMLElement)?.clientHeight ?? 0
+			this.footerHeight = (this.$refs.footer as HTMLElement)?.clientHeight ?? 0
+
+			// Get the header height which consists of table header and filters
+			const theadHeight = (this.$refs.thead as HTMLElement)?.clientHeight ?? 0
+			const filterHeight = (this.$refs.filters as HTMLElement)?.clientHeight ?? 0
+			this.headerHeight = theadHeight + filterHeight
 		},
 	},
 })