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panzoom.ts
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panzoom.ts
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/**
* Panzoom for panning and zooming elements using CSS transforms
* https://github.com/timmywil/panzoom
*
* Copyright Timmy Willison and other contributors
* Released under the MIT license
* https://github.com/timmywil/panzoom/blob/master/MIT-License.txt
*
*/
import { getDimensions, setStyle, setTransform } from './css'
import { destroyPointer, onPointer } from './events'
import isAttached from './isAttached'
import isSVGElement from './isSVGElement'
import { addPointer, getDistance, getMiddle, removePointer } from './pointers'
import './polyfills'
import shallowClone from './shallowClone'
import { PanOptions, PanzoomEvent, PanzoomObject, PanzoomOptions, ZoomOptions } from './types'
const defaultOptions: PanzoomOptions = {
animate: false,
cursor: 'move',
disablePan: false,
disableZoom: false,
disableXAxis: false,
disableYAxis: false,
duration: 200,
easing: 'ease-in-out',
exclude: [],
excludeClass: 'panzoom-exclude',
maxScale: 4,
minScale: 0.125,
panOnlyWhenZoomed: false,
relative: false,
setTransform,
startX: 0,
startY: 0,
startScale: 1,
step: 0.3
}
function Panzoom(
elem: HTMLElement | SVGElement,
options?: Omit<PanzoomOptions, 'force'>
): PanzoomObject {
if (!elem) {
throw new Error('Panzoom requires an element as an argument')
}
if (elem.nodeType !== 1) {
throw new Error('Panzoom requires an element with a nodeType of 1')
}
if (!isAttached(elem)) {
throw new Error('Panzoom should be called on elements that have been attached to the DOM')
}
options = {
...defaultOptions,
...options
}
const isSVG = isSVGElement(elem)
function setOptions(opts: Omit<PanzoomOptions, 'force'> = {}) {
for (const key in opts) {
if (opts.hasOwnProperty(key)) {
options[key] = opts[key]
}
}
// Handle option side-effects
if (opts.hasOwnProperty('cursor')) {
elem.style.cursor = opts.cursor
}
}
// Set overflow on the parent
const parent = elem.parentElement
parent.style.overflow = 'hidden'
parent.style.userSelect = 'none'
// This is important for mobile to
// prevent scrolling while panning
parent.style.touchAction = 'none'
// Set some default styles on the panzoom element
elem.style.cursor = options.cursor
elem.style.userSelect = 'none'
elem.style.touchAction = 'none'
// The default for HTML is '50% 50%'
// The default for SVG is '0 0'
// SVG can't be changed in IE
setStyle(
elem,
'transformOrigin',
typeof options.origin === 'string' ? options.origin : isSVG ? '0 0' : '50% 50%'
)
let x = 0
let y = 0
let scale = 1
let isPanning = false
zoom(options.startScale, { animate: false })
// Wait for scale to update
// for accurate dimensions
// to constrain initial values
setTimeout(() => {
pan(options.startX, options.startY, { animate: false })
})
function trigger(eventName: PanzoomEvent, detail: any, opts: PanzoomOptions) {
if (opts.silent) {
return
}
const event = new CustomEvent(eventName, { detail })
elem.dispatchEvent(event)
}
function setTransformWithEvent(eventName: PanzoomEvent, opts: PanzoomOptions) {
const value = { x, y, scale }
opts.setTransform(elem, value, opts)
trigger(eventName, value, opts)
trigger('panzoomchange', value, opts)
return value
}
function constrainXY(toX: number | string, toY: number | string, panOptions?: PanOptions) {
const opts = { ...options, ...panOptions }
const result = { x, y, opts }
if (!opts.force && (opts.disablePan || (opts.panOnlyWhenZoomed && scale === opts.startScale))) {
return result
}
toX = parseFloat(toX as string)
toY = parseFloat(toY as string)
if (!opts.disableXAxis) {
result.x = (opts.relative ? x : 0) + toX
}
if (!opts.disableYAxis) {
result.y = (opts.relative ? y : 0) + toY
}
if (opts.contain === 'inside') {
const dims = getDimensions(elem)
result.x = Math.max(
-dims.elem.margin.left - dims.parent.padding.left,
Math.min(
dims.parent.width -
dims.elem.width / scale -
dims.parent.padding.left -
dims.elem.margin.left -
dims.parent.border.left -
dims.parent.border.right,
result.x
)
)
result.y = Math.max(
-dims.elem.margin.top - dims.parent.padding.top,
Math.min(
dims.parent.height -
dims.elem.height / scale -
dims.parent.padding.top -
dims.elem.margin.top -
dims.parent.border.top -
dims.parent.border.bottom,
result.y
)
)
} else if (opts.contain === 'outside') {
const dims = getDimensions(elem)
const diffHorizontal = (dims.elem.width - dims.elem.width / scale) / 2
const diffVertical = (dims.elem.height - dims.elem.height / scale) / 2
result.x = Math.max(
Math.min(result.x, (diffHorizontal - dims.parent.padding.left) / scale),
(-(dims.elem.width - dims.parent.width) -
dims.parent.padding.left -
dims.parent.border.left -
dims.parent.border.right +
diffHorizontal) /
scale
)
result.y = Math.max(
Math.min(result.y, (diffVertical - dims.parent.padding.top) / scale),
(-(dims.elem.height - dims.parent.height) -
dims.parent.padding.top -
dims.parent.border.top -
dims.parent.border.bottom +
diffVertical) /
scale
)
}
return result
}
function constrainScale(toScale: number, zoomOptions?: ZoomOptions) {
const opts = { ...options, ...zoomOptions }
const result = { scale, opts }
if (!opts.force && opts.disableZoom) {
return result
}
result.scale = Math.min(Math.max(toScale, opts.minScale), opts.maxScale)
return result
}
function pan(toX: number | string, toY: number | string, panOptions?: PanOptions) {
const result = constrainXY(toX, toY, panOptions)
const opts = result.opts
x = result.x
y = result.y
return setTransformWithEvent('panzoompan', opts)
}
function zoom(toScale: number, zoomOptions?: ZoomOptions) {
const result = constrainScale(toScale, zoomOptions)
const opts = result.opts
if (!opts.force && opts.disableZoom) {
return
}
toScale = result.scale
if (opts.focal) {
// The difference between the point after the scale and the point before the scale
// plus the current translation after the scale
// neutralized to no scale (as the transform scale will apply to the translation)
const focal = opts.focal
const toX = (focal.x / toScale - focal.x / scale + x * toScale) / toScale
const toY = (focal.y / toScale - focal.y / scale + y * toScale) / toScale
const panResult = constrainXY(toX, toY, { relative: false })
x = panResult.x
y = panResult.y
}
scale = toScale
return setTransformWithEvent('panzoomzoom', opts)
}
function zoomInOut(isIn: boolean, zoomOptions?: ZoomOptions) {
const opts = { ...options, animate: true, ...zoomOptions }
return zoom(scale * Math.exp((isIn ? 1 : -1) * opts.step), opts)
}
function zoomIn(zoomOptions?: ZoomOptions) {
return zoomInOut(true, zoomOptions)
}
function zoomOut(zoomOptions?: ZoomOptions) {
return zoomInOut(false, zoomOptions)
}
function zoomToPoint(
toScale: number,
point: { clientX: number; clientY: number },
zoomOptions?: ZoomOptions
) {
const dims = getDimensions(elem)
// Instead of thinking of operating on the panzoom element,
// think of operating on the area inside the panzoom
// element's parent
// Subtract padding and border
const effectiveArea = {
width:
dims.parent.width -
dims.parent.padding.left -
dims.parent.padding.right -
dims.parent.border.left -
dims.parent.border.right,
height:
dims.parent.height -
dims.parent.padding.top -
dims.parent.padding.bottom -
dims.parent.border.top -
dims.parent.border.bottom
}
// Adjust the clientX/clientY to ignore the area
// outside the effective area
let clientX =
point.clientX -
dims.parent.left -
dims.parent.padding.left -
dims.parent.border.left -
dims.elem.margin.left
let clientY =
point.clientY -
dims.parent.top -
dims.parent.padding.top -
dims.parent.border.top -
dims.elem.margin.top
// Adjust the clientX/clientY for HTML elements,
// because they have a transform-origin of 50% 50%
if (!isSVG) {
clientX -= dims.elem.width / scale / 2
clientY -= dims.elem.height / scale / 2
}
// Convert the mouse point from it's position over the
// effective area before the scale to the position
// over the effective area after the scale.
const focal = {
x: (clientX / effectiveArea.width) * (effectiveArea.width * toScale),
y: (clientY / effectiveArea.height) * (effectiveArea.height * toScale)
}
return zoom(toScale, { ...zoomOptions, focal, animate: false })
}
function zoomWithWheel(event: WheelEvent, zoomOptions?: ZoomOptions) {
// Need to prevent the default here
// or it conflicts with regular page scroll
event.preventDefault()
const opts = { ...options, ...zoomOptions }
// Normalize to deltaX in case shift modifier is used on Mac
const delta = event.deltaY === 0 && event.deltaX ? event.deltaX : event.deltaY
const wheel = delta < 0 ? 1 : -1
const toScale = constrainScale(scale * Math.exp((wheel * opts.step) / 3), opts).scale
return zoomToPoint(toScale, event, opts)
}
function reset(resetOptions?: PanzoomOptions) {
const opts = { ...options, animate: true, ...resetOptions }
const panResult = constrainXY(opts.startX, opts.startY, opts)
x = panResult.x
y = panResult.y
scale = constrainScale(opts.startScale, opts).scale
return setTransformWithEvent('panzoomreset', opts)
}
let origX: number
let origY: number
let startClientX: number
let startClientY: number
let startScale: number
let startDistance: number
const pointers: PointerEvent[] = []
function handleDown(event: PointerEvent) {
// Don't handle this event if the target is excluded
if (
event.target &&
((event.target as Element).classList.contains(options.excludeClass) ||
options.exclude.indexOf(event.target as Element) > -1)
) {
return
}
addPointer(pointers, event)
isPanning = true
event.preventDefault()
event.stopPropagation()
origX = x
origY = y
trigger('panzoomstart', { x, y, scale }, options)
// This works whether there are multiple
// pointers or not
const point = getMiddle(pointers)
startClientX = point.clientX
startClientY = point.clientY
startScale = scale
startDistance = getDistance(pointers)
}
function move(event: PointerEvent) {
if (
!isPanning ||
origX === undefined ||
origY === undefined ||
startClientX === undefined ||
startClientY === undefined
) {
return
}
addPointer(pointers, event)
const current = getMiddle(pointers)
if (pointers.length > 1) {
// Use the distance between the first 2 pointers
// to determine the current scale
const diff = getDistance(pointers) - startDistance
const toScale = constrainScale((diff * options.step) / 80 + startScale).scale
zoomToPoint(toScale, current)
}
pan(
origX + (current.clientX - startClientX) / scale,
origY + (current.clientY - startClientY) / scale,
{
animate: false
}
)
}
function handleUp(event: PointerEvent) {
// Note: don't remove all pointers
// Can restart without having to reinitiate all of them
// Remove the pointer regardless of the isPanning state
removePointer(pointers, event)
if (!isPanning) {
return
}
// Only call panzoomend once
if (pointers.length === 1) {
trigger('panzoomend', { x, y, scale }, options)
}
isPanning = false
origX = origY = startClientX = startClientY = undefined
}
if (!options.disablePan) {
onPointer('down', elem, handleDown)
onPointer('move', document, move, { passive: true })
onPointer('up', document, handleUp, { passive: true })
}
function destroy() {
destroyPointer('down', elem, handleDown)
destroyPointer('move', document, move)
destroyPointer('up', document, handleUp)
}
return {
destroy,
getPan: () => ({ x, y }),
getScale: () => scale,
getOptions: () => shallowClone(options),
pan,
reset,
setOptions,
setStyle: (name: string, value: string) => setStyle(elem, name, value),
zoom,
zoomIn,
zoomOut,
zoomToPoint,
zoomWithWheel
}
}
Panzoom.defaultOptions = defaultOptions
export default Panzoom