alexandrusoare commented on code in PR #45090: URL: https://github.com/apache/superset/pull/45090#discussion_r4348001222
########## superset-frontend/src/features/canvas/CanvasGridSurface.tsx: ########## @@ -0,0 +1,666 @@ +/** + * Licensed to the Apache Software Foundation (ASF) under one + * or more contributor license agreements. See the NOTICE file + * distributed with this work for additional information + * regarding copyright ownership. The ASF licenses this file + * to you under the Apache License, Version 2.0 (the + * "License"); you may not use this file except in compliance + * with the License. You may obtain a copy of the License at + * + * http://www.apache.org/licenses/LICENSE-2.0 + * + * Unless required by applicable law or agreed to in writing, + * software distributed under the License is distributed on an + * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY + * KIND, either express or implied. See the License for the + * specific language governing permissions and limitations + * under the License. + */ + +/** + * @fileoverview One grid of a canvas, with drag and resize built in. + * + * There is no edit mode: a user who may edit gets a drag grip and a resize + * corner on each widget, on the canvas as they view it. A user who may not + * gets the same grid with no handles. Dragging never covers the widget's own + * surface, so a filter or chart underneath stays clickable. + * + * While a gesture is live the widget follows the pointer and a dashed outline + * marks the cells it would take; releasing persists exactly those cells. + */ + +import { + PointerEvent as ReactPointerEvent, + KeyboardEvent as ReactKeyboardEvent, + ReactNode, + useCallback, + useEffect, + useRef, + useState, +} from 'react'; +import { css, styled } from '@apache-superset/core/theme'; +import { t } from '@apache-superset/core/translation'; +import { Icons } from '@superset-ui/core/components'; +import { + GridMetrics, + gridDelta, + movedPlacement, + NO_DELTA, + RESIZE_CORNERS, + type ResizeCorner, + resizedPlacement, + samePlacement, +} from './gridGeometry'; +import { previewGrid } from './resolveGrid'; +import type { GridPlacement, SpanConstraints } from './types'; + +type GestureKind = 'move' | 'resize'; + +interface Gesture { + nodeId: string; + kind: GestureKind; + pointerId: number; + startX: number; + startY: number; + /** + * Page scroll when the widget was grabbed. Pointer coordinates are relative + * to the viewport, so scrolling mid-gesture moves the content under a still + * pointer; without this the drag would report no movement at all. + */ + startScrollX: number; + startScrollY: number; + dx: number; + dy: number; + /** + * Where the widget sat when it was grabbed. The gesture resolves against + * this, not against the current placement: a write landing mid-gesture (a + * sibling's drop pushing this one down, or a draft poll) would otherwise + * move the ground under the pointer and persist the drop relative to a row + * the user never aimed at. + */ + origin: GridPlacement; + /** + * Whether this gesture is actually dragging yet. One begun on a handle is + * armed at once; one begun on the widget body waits until the pointer has + * travelled `DRAG_THRESHOLD`, so a press that turns out to be a click + * reaches the widget underneath instead of nudging it. + */ + armed: boolean; + /** For a resize, the corner being dragged; the opposite one stays put. */ + corner: ResizeCorner; +} + +/** Pixels of travel before a press on a widget body becomes a drag. */ +const DRAG_THRESHOLD = 4; + +/** A gesture's movement over the page content, scrolling included. */ +const travelled = (gesture: Gesture, clientX: number, clientY: number) => ({ + dx: clientX - gesture.startX + (window.scrollX - gesture.startScrollX), + dy: clientY - gesture.startY + (window.scrollY - gesture.startScrollY), +}); + +const Grid = styled.div<GridMetrics>` + display: grid; + grid-template-columns: repeat(${({ columns }) => columns}, minmax(0, 1fr)); + grid-auto-rows: ${({ rowUnit }) => rowUnit}px; + gap: ${({ gap }) => gap}px; +`; + +const GridItem = styled.div<{ + placement?: GridPlacement; + dragging?: boolean; + offset?: { x: number; y: number }; +}>` + ${({ placement, dragging, offset }) => css` + min-width: 0; + min-height: 0; + position: relative; + ${ + placement && + css` + grid-column: ${placement.col} / span ${placement.colSpan}; + grid-row: ${placement.row} / span ${placement.rowSpan}; + ` + } + ${ + dragging && + offset && + css` + /* Follow the pointer without reflowing the grid under it. */ + transform: translate(${offset.x}px, ${offset.y}px); + z-index: 2; + opacity: 0.85; + ` + } + `} +`; + +/** + * Where the widget being dragged will land. No error state: the neighbours + * are already rendered where they will end up, so an overlap shows as them + * moving aside rather than as a warning colour here. + */ +const DropPreview = styled.div<{ placement: GridPlacement }>` + ${({ theme, placement }) => css` + grid-column: ${placement.col} / span ${placement.colSpan}; + grid-row: ${placement.row} / span ${placement.rowSpan}; + border: 2px dashed ${theme.colorPrimary}; + border-radius: ${theme.borderRadius}px; + background: ${theme.colorPrimaryBg}; + pointer-events: none; + z-index: 1; + `} +`; + +/** + * Wraps a widget so its handles can sit on top of it. The handles stay hidden + * until the pointer is over the widget or a handle has focus, so a canvas at + * rest looks the same whether or not the user may edit it. + * + * Only the innermost hovered widget shows its handles and its outline: + * `:hover` matches every ancestor, so a container would otherwise light up + * alongside whichever of its children the pointer is actually over. + */ +const Interactive = styled.div` + ${({ theme }) => css` + height: 100%; + position: relative; + border-radius: ${theme.borderRadius}px; + transition: box-shadow ${theme.motionDurationMid}; + + /* Direct children only: hovering a container must not reveal the + handles of every widget nested inside it. */ + & > .canvas-handle { + opacity: 0; + /* + * Transparent is not absent: without this a hidden handle still wins + * the hit test over whatever it happens to sit above. + */ + pointer-events: none; + transition: opacity ${theme.motionDurationMid}; + } + + &:hover:not(:has(.canvas-interactive:hover)) { + /* Borderless widgets (a metric tile, say) otherwise give no clue which + widget the handles belong to. */ + box-shadow: 0 0 0 1px ${theme.colorBorder}; + } + + &:hover:not(:has(.canvas-interactive:hover)) > .canvas-handle, + & > .canvas-handle:focus-visible { + opacity: 1; + pointer-events: auto; + } + `} +`; + +/** Step between a container's handles and its children's, in size units. */ +const HANDLE_STEP = 8; +/** Size units a handle itself needs, so an offset can leave room for it. */ +const HANDLE_BOX = 7; + +/** + * How far a nested grid's handles sit from the widget's edge. + * + * Nesting steps the offset so a container's handle never lands exactly on its + * child's, but it is clamped to the widget's own rendered box: pushing past + * that would put the handle over the *next* widget, where it would take + * presses meant for that one. + */ +const handleOffset = ( + sizeUnit: number, + depth: number, + extent: number, +): number => { + const room = Math.max(sizeUnit, extent - sizeUnit * HANDLE_BOX); + return Math.min(sizeUnit * (1 + depth * HANDLE_STEP), room); +}; + +/** + * The widget itself, kept inside the cells it was given. + * + * A widget renders at its natural height — a table with every row, say — so + * without this it spills past its own box and over whatever is below. The + * handles are siblings rather than children, so they stay pinned to the box + * while the content scrolls behind them. + */ +const Content = styled.div` + height: 100%; + overflow: auto; +`; + +const Grip = styled.button<{ depth: number; extent: number }>` + ${({ theme, depth, extent }) => css` + position: absolute; + top: ${handleOffset(theme.sizeUnit, depth, extent)}px; + /* Deeper handles above shallower ones: the innermost wins a shared spot. */ + z-index: ${3 + depth}; + /* + * Left of both the north-east resize corner (4 units at the corner) and a + * widget's own controls, which step aside to 5 units while a plan is open + * and are 8 units wide (see WithQuery's .canvas-widget-controls). These + * handles sit above them in the stack, so overlapping would swallow + * presses meant for the menu. + */ + right: ${theme.sizeUnit * 14}px; + display: flex; + align-items: center; + justify-content: center; + padding: ${theme.sizeUnit / 2}px; + border: 1px solid ${theme.colorBorder}; + border-radius: ${theme.borderRadiusSM}px; + background: ${theme.colorBgElevated}; + color: ${theme.colorTextSecondary}; + cursor: grab; + touch-action: none; + + &:active { + cursor: grabbing; + } + `} +`; + +/** Human-readable names for the four corners, for the handle labels. */ +const CORNER_NAMES: Record<ResizeCorner, () => string> = { + nw: () => t('top left'), + ne: () => t('top right'), + sw: () => t('bottom left'), + se: () => t('bottom right'), +}; + +const ResizeCorner = styled.button<{ + corner: ResizeCorner; + depth: number; + extent: number; +}>` + ${({ theme, corner, depth, extent }) => { + const west = corner === 'nw' || corner === 'sw'; + const north = corner === 'nw' || corner === 'ne'; + /* + * Stepped like the grip: a container's box shares its edges with its + * first and last child's, and the container's handles paint later, so + * sharing the pixel would make the child's corner unreachable. + */ + const inset = + depth === 0 ? 0 : handleOffset(theme.sizeUnit, depth - 1, extent); + return css` + position: absolute; + ${west ? 'left' : 'right'}: ${inset}px; + ${north ? 'top' : 'bottom'}: ${inset}px; + z-index: ${3 + depth}; + width: ${theme.sizeUnit * 4}px; + height: ${theme.sizeUnit * 4}px; + padding: 0; + border: none; + background: transparent; + cursor: ${west === north ? 'nwse-resize' : 'nesw-resize'}; + touch-action: none; + + /* A two-line corner, the conventional resize affordance. */ + &::after { + content: ''; + position: absolute; + ${west ? 'left' : 'right'}: ${theme.sizeUnit / 2}px; + ${north ? 'top' : 'bottom'}: ${theme.sizeUnit / 2}px; + width: ${theme.sizeUnit * 2}px; + height: ${theme.sizeUnit * 2}px; + border-${west ? 'left' : 'right'}: 2px solid ${theme.colorTextTertiary}; + border-${north ? 'top' : 'bottom'}: 2px solid + ${theme.colorTextTertiary}; + } + `; + }} +`; + +/** The grid's content width, kept current as the viewport changes. */ +function useElementWidth(): [(element: HTMLDivElement | null) => void, number] { + const [element, setElement] = useState<HTMLDivElement | null>(null); + const [width, setWidth] = useState(0); + + useEffect(() => { + if (!element) return undefined; + const measure = () => setWidth(element.clientWidth); + measure(); + if (typeof ResizeObserver === 'undefined') return undefined; + const observer = new ResizeObserver(measure); + observer.observe(element); + return () => observer.disconnect(); + }, [element]); + + return [setElement, width]; +} + +export interface CanvasGridSurfaceProps { + childIds: string[]; + columns: number; + gap: number; + rowUnit: number; + placements: Record<string, GridPlacement>; + constraints: Record<string, SpanConstraints>; + /** Whether the user may drag and resize these widgets. */ + editable: boolean; + /** + * How deeply this grid is nested. A container's box begins where its first + * child's does and its handles paint last, so without an offset per level a + * container's grip would sit over its child's and swallow the click. + */ + depth: number; + onPlace: (nodeId: string, placement: GridPlacement) => void; + renderNode: (nodeId: string) => ReactNode; +} + +export default function CanvasGridSurface({ + childIds, + columns, + gap, + rowUnit, + placements, + constraints, + editable, + depth, + onPlace, + renderNode, +}: CanvasGridSurfaceProps) { + const [gridRef, width] = useElementWidth(); + const [gesture, setGesture] = useState<Gesture>(); + // The handlers read the gesture directly, so committing never runs as a + // side effect inside a state updater. + const live = useRef<Gesture>(); + + const update = useCallback((next: Gesture | undefined) => { + live.current = next; + setGesture(next); + }, []); + + /** Where `from` would land given a pointer delta, in whole grid units. */ + const targetOf = useCallback( + ( + nodeId: string, + kind: GestureKind, + from: GridPlacement, + dx: number, + dy: number, + corner: ResizeCorner = 'se', + ) => { + const metrics: GridMetrics = { columns, gap, rowUnit }; + const delta = width > 0 ? gridDelta(dx, dy, width, metrics) : NO_DELTA; + return kind === 'move' + ? movedPlacement(from, delta, columns) + : resizedPlacement(from, delta, columns, constraints[nodeId], corner); + }, + [width, columns, gap, rowUnit, constraints], + ); + + /** + * Persists `next` for `nodeId`, where `from` is the placement the gesture + * resolved against. + * + * Both no-op checks matter. A gesture that moved nothing resolves back to + * `from`, and sending that would write the geometry the widget had when it + * was grabbed over anything that landed while the button was held -- a plain + * click on a handle would revert a draft poll or another editor's resize. + * Comparing with the current placement then drops a gesture that happens to + * land exactly where the widget already sits. + */ + const commit = useCallback( + (nodeId: string, next: GridPlacement | undefined, from: GridPlacement) => { + const placement = placements[nodeId]; + if (!next || !placement) return; + if (samePlacement(next, from) || samePlacement(next, placement)) return; + onPlace(nodeId, next); + }, + [onPlace, placements], + ); + + const begin = + ( + nodeId: string, + kind: GestureKind, + armed = true, + corner: ResizeCorner = 'se', + ) => + (event: ReactPointerEvent<HTMLElement>) => { + if (event.button !== 0) return; + // One gesture at a time. A second finger on another handle also reports + // button 0, and letting it replace the live gesture would strand the + // first pointer: its move and up events fail the pointerId guards, so + // its drag would be dropped without ever being committed. + if (live.current) return; + const origin = placements[nodeId]; + if (!origin) return; + // A deferred gesture must leave the press alone until it becomes a + // drag, or a click on a chart would never reach it. + if (armed) { Review Comment: Done. A deferred press can't stopPropagation (the click has to land), so there's now a WeakSet of claimed presses — the innermost grid runs first and takes it, the rest stand down. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. 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