--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/.cms/lib/codemirror/src/display/scrolling.js	Fri Oct 11 22:40:23 2024 +0000
@@ -0,0 +1,186 @@
+import { Pos } from "../line/pos.js"
+import { cursorCoords, displayHeight, displayWidth, estimateCoords, paddingTop, paddingVert, scrollGap, textHeight } from "../measurement/position_measurement.js"
+import { gecko, phantom } from "../util/browser.js"
+import { elt } from "../util/dom.js"
+import { signalDOMEvent } from "../util/event.js"
+
+import { startWorker } from "./highlight_worker.js"
+import { alignHorizontally } from "./line_numbers.js"
+import { updateDisplaySimple } from "./update_display.js"
+
+// SCROLLING THINGS INTO VIEW
+
+// If an editor sits on the top or bottom of the window, partially
+// scrolled out of view, this ensures that the cursor is visible.
+export function maybeScrollWindow(cm, rect) {
+  if (signalDOMEvent(cm, "scrollCursorIntoView")) return
+
+  let display = cm.display, box = display.sizer.getBoundingClientRect(), doScroll = null
+  let doc = display.wrapper.ownerDocument
+  if (rect.top + box.top < 0) doScroll = true
+  else if (rect.bottom + box.top > (doc.defaultView.innerHeight || doc.documentElement.clientHeight)) doScroll = false
+  if (doScroll != null && !phantom) {
+    let scrollNode = elt("div", "\u200b", null, `position: absolute;
+                         top: ${rect.top - display.viewOffset - paddingTop(cm.display)}px;
+                         height: ${rect.bottom - rect.top + scrollGap(cm) + display.barHeight}px;
+                         left: ${rect.left}px; width: ${Math.max(2, rect.right - rect.left)}px;`)
+    cm.display.lineSpace.appendChild(scrollNode)
+    scrollNode.scrollIntoView(doScroll)
+    cm.display.lineSpace.removeChild(scrollNode)
+  }
+}
+
+// Scroll a given position into view (immediately), verifying that
+// it actually became visible (as line heights are accurately
+// measured, the position of something may 'drift' during drawing).
+export function scrollPosIntoView(cm, pos, end, margin) {
+  if (margin == null) margin = 0
+  let rect
+  if (!cm.options.lineWrapping && pos == end) {
+    // Set pos and end to the cursor positions around the character pos sticks to
+    // If pos.sticky == "before", that is around pos.ch - 1, otherwise around pos.ch
+    // If pos == Pos(_, 0, "before"), pos and end are unchanged
+    end = pos.sticky == "before" ? Pos(pos.line, pos.ch + 1, "before") : pos
+    pos = pos.ch ? Pos(pos.line, pos.sticky == "before" ? pos.ch - 1 : pos.ch, "after") : pos
+  }
+  for (let limit = 0; limit < 5; limit++) {
+    let changed = false
+    let coords = cursorCoords(cm, pos)
+    let endCoords = !end || end == pos ? coords : cursorCoords(cm, end)
+    rect = {left: Math.min(coords.left, endCoords.left),
+            top: Math.min(coords.top, endCoords.top) - margin,
+            right: Math.max(coords.left, endCoords.left),
+            bottom: Math.max(coords.bottom, endCoords.bottom) + margin}
+    let scrollPos = calculateScrollPos(cm, rect)
+    let startTop = cm.doc.scrollTop, startLeft = cm.doc.scrollLeft
+    if (scrollPos.scrollTop != null) {
+      updateScrollTop(cm, scrollPos.scrollTop)
+      if (Math.abs(cm.doc.scrollTop - startTop) > 1) changed = true
+    }
+    if (scrollPos.scrollLeft != null) {
+      setScrollLeft(cm, scrollPos.scrollLeft)
+      if (Math.abs(cm.doc.scrollLeft - startLeft) > 1) changed = true
+    }
+    if (!changed) break
+  }
+  return rect
+}
+
+// Scroll a given set of coordinates into view (immediately).
+export function scrollIntoView(cm, rect) {
+  let scrollPos = calculateScrollPos(cm, rect)
+  if (scrollPos.scrollTop != null) updateScrollTop(cm, scrollPos.scrollTop)
+  if (scrollPos.scrollLeft != null) setScrollLeft(cm, scrollPos.scrollLeft)
+}
+
+// Calculate a new scroll position needed to scroll the given
+// rectangle into view. Returns an object with scrollTop and
+// scrollLeft properties. When these are undefined, the
+// vertical/horizontal position does not need to be adjusted.
+function calculateScrollPos(cm, rect) {
+  let display = cm.display, snapMargin = textHeight(cm.display)
+  if (rect.top < 0) rect.top = 0
+  let screentop = cm.curOp && cm.curOp.scrollTop != null ? cm.curOp.scrollTop : display.scroller.scrollTop
+  let screen = displayHeight(cm), result = {}
+  if (rect.bottom - rect.top > screen) rect.bottom = rect.top + screen
+  let docBottom = cm.doc.height + paddingVert(display)
+  let atTop = rect.top < snapMargin, atBottom = rect.bottom > docBottom - snapMargin
+  if (rect.top < screentop) {
+    result.scrollTop = atTop ? 0 : rect.top
+  } else if (rect.bottom > screentop + screen) {
+    let newTop = Math.min(rect.top, (atBottom ? docBottom : rect.bottom) - screen)
+    if (newTop != screentop) result.scrollTop = newTop
+  }
+
+  let gutterSpace = cm.options.fixedGutter ? 0 : display.gutters.offsetWidth
+  let screenleft = cm.curOp && cm.curOp.scrollLeft != null ? cm.curOp.scrollLeft : display.scroller.scrollLeft - gutterSpace
+  let screenw = displayWidth(cm) - display.gutters.offsetWidth
+  let tooWide = rect.right - rect.left > screenw
+  if (tooWide) rect.right = rect.left + screenw
+  if (rect.left < 10)
+    result.scrollLeft = 0
+  else if (rect.left < screenleft)
+    result.scrollLeft = Math.max(0, rect.left + gutterSpace - (tooWide ? 0 : 10))
+  else if (rect.right > screenw + screenleft - 3)
+    result.scrollLeft = rect.right + (tooWide ? 0 : 10) - screenw
+  return result
+}
+
+// Store a relative adjustment to the scroll position in the current
+// operation (to be applied when the operation finishes).
+export function addToScrollTop(cm, top) {
+  if (top == null) return
+  resolveScrollToPos(cm)
+  cm.curOp.scrollTop = (cm.curOp.scrollTop == null ? cm.doc.scrollTop : cm.curOp.scrollTop) + top
+}
+
+// Make sure that at the end of the operation the current cursor is
+// shown.
+export function ensureCursorVisible(cm) {
+  resolveScrollToPos(cm)
+  let cur = cm.getCursor()
+  cm.curOp.scrollToPos = {from: cur, to: cur, margin: cm.options.cursorScrollMargin}
+}
+
+export function scrollToCoords(cm, x, y) {
+  if (x != null || y != null) resolveScrollToPos(cm)
+  if (x != null) cm.curOp.scrollLeft = x
+  if (y != null) cm.curOp.scrollTop = y
+}
+
+export function scrollToRange(cm, range) {
+  resolveScrollToPos(cm)
+  cm.curOp.scrollToPos = range
+}
+
+// When an operation has its scrollToPos property set, and another
+// scroll action is applied before the end of the operation, this
+// 'simulates' scrolling that position into view in a cheap way, so
+// that the effect of intermediate scroll commands is not ignored.
+function resolveScrollToPos(cm) {
+  let range = cm.curOp.scrollToPos
+  if (range) {
+    cm.curOp.scrollToPos = null
+    let from = estimateCoords(cm, range.from), to = estimateCoords(cm, range.to)
+    scrollToCoordsRange(cm, from, to, range.margin)
+  }
+}
+
+export function scrollToCoordsRange(cm, from, to, margin) {
+  let sPos = calculateScrollPos(cm, {
+    left: Math.min(from.left, to.left),
+    top: Math.min(from.top, to.top) - margin,
+    right: Math.max(from.right, to.right),
+    bottom: Math.max(from.bottom, to.bottom) + margin
+  })
+  scrollToCoords(cm, sPos.scrollLeft, sPos.scrollTop)
+}
+
+// Sync the scrollable area and scrollbars, ensure the viewport
+// covers the visible area.
+export function updateScrollTop(cm, val) {
+  if (Math.abs(cm.doc.scrollTop - val) < 2) return
+  if (!gecko) updateDisplaySimple(cm, {top: val})
+  setScrollTop(cm, val, true)
+  if (gecko) updateDisplaySimple(cm)
+  startWorker(cm, 100)
+}
+
+export function setScrollTop(cm, val, forceScroll) {
+  val = Math.max(0, Math.min(cm.display.scroller.scrollHeight - cm.display.scroller.clientHeight, val))
+  if (cm.display.scroller.scrollTop == val && !forceScroll) return
+  cm.doc.scrollTop = val
+  cm.display.scrollbars.setScrollTop(val)
+  if (cm.display.scroller.scrollTop != val) cm.display.scroller.scrollTop = val
+}
+
+// Sync scroller and scrollbar, ensure the gutter elements are
+// aligned.
+export function setScrollLeft(cm, val, isScroller, forceScroll) {
+  val = Math.max(0, Math.min(val, cm.display.scroller.scrollWidth - cm.display.scroller.clientWidth))
+  if ((isScroller ? val == cm.doc.scrollLeft : Math.abs(cm.doc.scrollLeft - val) < 2) && !forceScroll) return
+  cm.doc.scrollLeft = val
+  alignHorizontally(cm)
+  if (cm.display.scroller.scrollLeft != val) cm.display.scroller.scrollLeft = val
+  cm.display.scrollbars.setScrollLeft(val)
+}