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Improve performance for separator #10258

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Merged
merged 2 commits into from
Nov 28, 2025
Merged

Improve performance for separator #10258

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c36acb3
Improve performance for separator
haiodo Nov 28, 2025
10b0cae
Prevent mouse events during separator move
haiodo Nov 28, 2025
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51 changes: 40 additions & 11 deletions packages/ui/src/components/Separator.svelte
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Original file line number Diff line number Diff line change
Expand Up @@ -73,6 +73,17 @@
const remToPx = (rem: number): number => rem * fs
const pxToRem = (px: number): number => px / fs

const disableUserSelect = (): void => {
document.body.style.userSelect = 'none'
document.body.style.webkitUserSelect = 'none'
document.body.style.pointerEvents = 'none'
}
const enableUserSelect = (): void => {
document.body.style.userSelect = ''
document.body.style.webkitUserSelect = ''
document.body.style.pointerEvents = ''
}

const fetchSeparators = (): void => {
const res = getSeparators(name, float)
if (res !== null && !Array.isArray(res)) panel = res
Expand Down Expand Up @@ -313,29 +324,32 @@

function floatMouseMove (event: PointerEvent): void {
if (!isSeparate || parentSize === null || parentElement === null) return
const coord: number = Math.round(direction === 'horizontal' ? event.x - offset : event.y - offset)
const parentCoord: number = coord - parentSize.start
const coord: number = Math.round(direction === 'horizontal' ? event.clientX - offset : event.clientY - offset)
let parentCoord: number = coord - parentSize.start
const min = remToPx(panel.minSize === 'auto' ? 10 : panel.minSize)
const max = remToPx(panel.maxSize === 'auto' ? 30 : panel.maxSize)
// Clamp parentCoord to valid range to prevent panel from going off-screen
if (parentCoord < 0) parentCoord = 0
if (parentCoord > parentSize.size - separatorSize) parentCoord = parentSize.size - separatorSize
const newCoord =
side === 'start'
? parentSize.size - parentCoord < min - separatorSize
? parentSize.size - parentCoord < min
? min
: parentSize.size - parentCoord > max - separatorSize
: parentSize.size - parentCoord > max
? max
: parentSize.size - parentCoord
: parentCoord < min - separatorSize
: parentCoord < min
? min
: parentCoord > max - separatorSize
: parentCoord > max
? max
: parentCoord - separatorSize
: parentCoord
panel.size = pxToRem(newCoord)
setSize(parentElement, newCoord)
}

function normalMouseMove (event: PointerEvent): void {
if (!isSeparate || separatorMap === undefined || parentSize === null || separatorsSizes === null) return
const coord: number = Math.round(direction === 'horizontal' ? event.x - offset : event.y - offset)
const coord: number = Math.round(direction === 'horizontal' ? event.clientX - offset : event.clientY - offset)
let parentCoord: number = coord - parentSize.start
let prevCoord: number = separatorMap
.filter((f) => f.begin)
Expand Down Expand Up @@ -411,14 +425,14 @@
if (needAdd > 0) needAdd = resizeContainer(box.id, box.size, box.maxSize, needAdd, true)
})
}
separatorMap = separatorMap
}
applyStyles()
if ($panelstore.panel?.refit !== undefined) $panelstore.panel.refit()
}

function pointerUp (): void {
finalSeparation()
enableUserSelect()
document.removeEventListener('pointermove', pointerMove)
document.removeEventListener('pointerup', pointerUp)
}
Expand Down Expand Up @@ -457,6 +471,8 @@

function pointerDown (event: PointerEvent): void {
if (checkFullWidth()) return
event.preventDefault()
disableUserSelect()
prepareSeparation(event)
document.addEventListener('pointermove', pointerMove)
document.addEventListener('pointerup', pointerUp)
Expand All @@ -470,7 +486,6 @@
checkSibling()
return
}
offset = Math.round(direction === 'horizontal' ? event.offsetX : event.offsetY)
const p = parentElement.getBoundingClientRect()
parentSize =
direction === 'horizontal'
Expand All @@ -480,7 +495,20 @@
calculateSeparators()
generateMap()
applyStyles(true)
} else if (sState === SeparatorState.FLOAT) preparePanel()
// Calculate offset based on separator's actual position after generateMap
// prevCoord is the sum of all elements before separator + separators before
const prevCoord: number =
separatorMap
.filter((f) => f.begin)
.map((m) => m.size)
.reduce((prev, a) => prev + a, 0) + separatorsWide.before
const mousePos = direction === 'horizontal' ? event.clientX : event.clientY
// offset = mouse position relative to where separator should be
offset = mousePos - parentSize.start - prevCoord
} else if (sState === SeparatorState.FLOAT) {
offset = Math.round(direction === 'horizontal' ? event.offsetX : event.offsetY)
preparePanel()
}
document.body.style.cursor = direction === 'horizontal' ? 'col-resize' : 'row-resize'
}

Expand Down Expand Up @@ -658,6 +686,7 @@
.antiSeparator {
position: relative;
flex-shrink: 0;
touch-action: none;

&::after,
&::before {
Expand Down
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