Skip to content

fix: support pinch-to-zoom behavior #474

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Merged
rpearce merged 1 commit into from
Mar 26, 2024
Merged

fix: support pinch-to-zoom behavior #474

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
33 changes: 28 additions & 5 deletions source/Controlled.tsx
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -133,6 +133,7 @@ class ControlledBase extends Component<ControlledPropsWithDefaults, ControlledSt
private changeObserver: MutationObserver | undefined
private imgEl: SupportedImage | null = null
private imgElObserver: ResizeObserver | undefined
private isScaling = false
private prevBodyAttrs: BodyAttrs = defaultBodyAttrs
private styleModalImg: CSSProperties = {}
private touchYStart?: number
Expand Down Expand Up @@ -337,6 +338,7 @@ class ControlledBase extends Component<ControlledPropsWithDefaults, ControlledSt
window.removeEventListener('wheel', this.handleWheel)
window.removeEventListener('touchstart', this.handleTouchStart)
window.removeEventListener('touchmove', this.handleTouchMove)
window.removeEventListener('touchend', this.handleTouchEnd)
window.removeEventListener('touchcancel', this.handleTouchCancel)
window.removeEventListener('resize', this.handleResize)
document.removeEventListener('keydown', this.handleKeyDown, true)
Expand Down Expand Up @@ -532,20 +534,29 @@ class ControlledBase extends Component<ControlledPropsWithDefaults, ControlledSt
}

/**
* Start tracking the Y-axis
* Start tracking the Y-axis but abort if non-scroll
* gesture is detected (like pinch-to-zoom)
*/
handleTouchStart = (e: TouchEvent) => {
if (e.touches.length > 1) {
this.isScaling = true
return
}

if (e.changedTouches.length === 1 && e.changedTouches[0]) {
this.touchYStart = e.changedTouches[0].screenY
}
}

/**
* Track how far we've moved on the Y-axis
* and unzoom if we detect a "swipe"
* If the window isn't browser zoomed,
* track how far we've moved on the Y-axis
* and unzoom if we detect a swipe
*/
handleTouchMove = (e: TouchEvent) => {
if (this.touchYStart != null && e.changedTouches[0]) {
const browserScale = window.visualViewport?.scale ?? 1

if (!this.isScaling && browserScale <= 1 && this.touchYStart != null && e.changedTouches[0]) {
this.touchYEnd = e.changedTouches[0].screenY

const max = Math.max(this.touchYStart, this.touchYEnd)
Expand All @@ -562,9 +573,19 @@ class ControlledBase extends Component<ControlledPropsWithDefaults, ControlledSt
}

/**
* Reset the Y-axis start and end tracking points
* Reset the scaling check and the Y-axis start and end tracking points
*/
handleTouchEnd = () => {
this.isScaling = false
this.touchYStart = undefined
this.touchYEnd = undefined
}

/**
* Reset the scaling check and the Y-axis start and end tracking points
*/
handleTouchCancel = () => {
this.isScaling = false
this.touchYStart = undefined
this.touchYEnd = undefined
}
Expand Down Expand Up @@ -592,6 +613,7 @@ class ControlledBase extends Component<ControlledPropsWithDefaults, ControlledSt
window.addEventListener('wheel', this.handleWheel, { passive: true })
window.addEventListener('touchstart', this.handleTouchStart, { passive: true })
window.addEventListener('touchmove', this.handleTouchMove, { passive: true })
window.addEventListener('touchend', this.handleTouchEnd, { passive: true })
window.addEventListener('touchcancel', this.handleTouchCancel, { passive: true })
document.addEventListener('keydown', this.handleKeyDown, true)

Expand Down Expand Up @@ -620,6 +642,7 @@ class ControlledBase extends Component<ControlledPropsWithDefaults, ControlledSt
window.removeEventListener('wheel', this.handleWheel)
window.removeEventListener('touchstart', this.handleTouchStart)
window.removeEventListener('touchmove', this.handleTouchMove)
window.removeEventListener('touchend', this.handleTouchEnd)
window.removeEventListener('touchcancel', this.handleTouchCancel)
document.removeEventListener('keydown', this.handleKeyDown, true)

Expand Down