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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,179 @@ | ||
| import { Events } from "../events"; | ||
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| type Point = { x: number, y: number }; | ||
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| class LassoSelection { | ||
| activate: () => void; | ||
| deactivate: () => void; | ||
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| constructor(events: Events, parent: HTMLElement, mask: { canvas: HTMLCanvasElement, context: CanvasRenderingContext2D }) { | ||
| let points: Point[] = []; | ||
| let currentPoint: Point = null; | ||
| let lastPointTime = 0; | ||
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| // create svg | ||
| const svg = document.createElementNS("http://www.w3.org/2000/svg", "svg"); | ||
| svg.id = 'lasso-select-svg'; | ||
| svg.classList.add('select-svg'); | ||
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| // create polyline element | ||
| const polyline = document.createElementNS(svg.namespaceURI, 'polyline') as SVGPolylineElement; | ||
| polyline.setAttribute('fill', 'none'); | ||
| polyline.setAttribute('stroke-width', '1'); | ||
| polyline.setAttribute('stroke-dasharray', '5, 5'); | ||
| polyline.setAttribute('stroke-dashoffset', '0'); | ||
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| // create canvas | ||
| const { canvas, context } = mask; | ||
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| const paint = () => { | ||
| polyline.setAttribute('points', [...points, currentPoint].reduce((prev, current) => prev + `${current.x}, ${current.y} `, "")); | ||
| polyline.setAttribute('stroke', isClosed() ? '#fa6' : '#f60'); | ||
| }; | ||
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| const dist = (a: Point, b: Point) => { | ||
| return Math.sqrt((a.x - b.x) ** 2 + (a.y - b.y) ** 2); | ||
| }; | ||
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| const isClosed = () => { | ||
| return points.length > 1 && dist(currentPoint, points[0]) < 8; | ||
| }; | ||
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| let dragId: number | undefined; | ||
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| const update = (e: PointerEvent) => { | ||
| currentPoint = {x: e.offsetX, y: e.offsetY}; | ||
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| const distance = points.length === 0 ? 0 : dist(currentPoint, points[points.length - 1]); | ||
| const millis = Date.now() - lastPointTime; | ||
| const preventCorners = distance > 20; | ||
| const slowNarrowSpacing = millis > 500 && distance > 2; | ||
| const fasterMediumSpacing = millis > 200 && distance > 10; | ||
| const firstPoints = points.length === 0; | ||
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| if (dragId !== undefined && (preventCorners || slowNarrowSpacing || fasterMediumSpacing || firstPoints)) { | ||
| points.push(currentPoint); | ||
| lastPointTime = Date.now(); | ||
| paint(); | ||
| } | ||
| }; | ||
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| const pointerdown = (e: PointerEvent) => { | ||
| if (dragId === undefined && (e.pointerType === 'mouse' ? e.button === 0 : e.isPrimary)) { | ||
| e.preventDefault(); | ||
| e.stopPropagation(); | ||
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| dragId = e.pointerId; | ||
| parent.setPointerCapture(dragId); | ||
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| // initialize canvas | ||
| if (canvas.width !== parent.clientWidth || canvas.height !== parent.clientHeight) { | ||
| canvas.width = parent.clientWidth; | ||
| canvas.height = parent.clientHeight; | ||
| } | ||
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| // clear canvas | ||
| context.clearRect(0, 0, canvas.width, canvas.height); | ||
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| // display it | ||
| canvas.style.display = 'inline'; | ||
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| update(e); | ||
| } | ||
| }; | ||
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| const pointermove = (e: PointerEvent) => { | ||
| if (dragId !== undefined) { | ||
| e.preventDefault(); | ||
| e.stopPropagation(); | ||
| } | ||
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| update(e); | ||
| }; | ||
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| const dragEnd = () => { | ||
| parent.releasePointerCapture(dragId); | ||
| dragId = undefined; | ||
| canvas.style.display = 'none'; | ||
| }; | ||
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| const pointerup = (e: PointerEvent) => { | ||
| if (e.pointerId === dragId) { | ||
| e.preventDefault(); | ||
| e.stopPropagation(); | ||
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| dragEnd(); | ||
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| commitSelection(e); | ||
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| events.fire( | ||
| 'select.byMask', | ||
| e.shiftKey ? 'add' : (e.ctrlKey ? 'remove' : 'set'), | ||
| canvas, | ||
| context | ||
| ); | ||
| } | ||
| }; | ||
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| const commitSelection = (e: PointerEvent) => { | ||
| // initialize canvas | ||
| if (canvas.width !== parent.clientWidth || canvas.height !== parent.clientHeight) { | ||
| canvas.width = parent.clientWidth; | ||
| canvas.height = parent.clientHeight; | ||
| } | ||
|
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| // clear canvas | ||
| context.clearRect(0, 0, canvas.width, canvas.height); | ||
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| context.beginPath(); | ||
| context.fillStyle = '#f60'; | ||
| context.beginPath(); | ||
| points.forEach((p, idx) => { | ||
| if (idx === 0) { | ||
| context.moveTo(p.x, p.y); | ||
| } | ||
| else { | ||
| context.lineTo(p.x, p.y); | ||
| } | ||
| }); | ||
| context.closePath(); | ||
| context.fill(); | ||
|
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| events.fire( | ||
| 'select.byMask', | ||
| e.shiftKey ? 'add' : (e.ctrlKey ? 'remove' : 'set'), | ||
| canvas, | ||
| context | ||
| ); | ||
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| points = []; | ||
| paint(); | ||
| }; | ||
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| this.activate = () => { | ||
| svg.style.display = 'inline'; | ||
| parent.style.display = 'block'; | ||
| parent.addEventListener('pointerdown', pointerdown); | ||
| parent.addEventListener('pointermove', pointermove); | ||
| parent.addEventListener('pointerup', pointerup); | ||
| }; | ||
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| this.deactivate = () => { | ||
| // cancel active operation | ||
| if (dragId !== undefined) { | ||
| dragEnd(); | ||
| } | ||
| svg.style.display = 'none'; | ||
| parent.style.display = 'none'; | ||
| parent.removeEventListener('pointerdown', pointerdown); | ||
| parent.removeEventListener('pointermove', pointermove); | ||
| parent.removeEventListener('pointerup', pointerup); | ||
| }; | ||
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| svg.appendChild(polyline); | ||
| parent.appendChild(svg); | ||
| } | ||
| } | ||
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| export { LassoSelection }; |
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