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1821 1822 1823 1824 1825 1826 1827 1828 1829 1830 1831 1832 1833 1834 1835 1836 1837 1838 1839 1840 1841 1842 1843 1844 1845 1846 1847 1848 1849 1850 1851 1852 1853 1854 1855 1856 1857 1858 1859 1860 1861 1862 1863 1864 1865 1866 1867 1868 1869 1870 1871 1872 1873 1874 1875 1876 1877 1878 1879 1880 1881 1882 1883 1884 1885 1886 1887 1888 1889 1890 1891 1892 1893 1894 1895 1896 1897 1898 1899 1900 1901 1902 1903 | import { useEffect, useCallback } from 'react' import type { ConstructionState, ConstructionElement, EuclidViewportState, PropositionDef, ConstructionPoint, ActiveTool, } from '../types' import type { FactStore } from '../engine/factStore' import { mergeProofFacts } from '../engine/factStore' import type { ProofFact } from '../engine/facts' import type { IntersectionCandidate } from '../types' import type { PostCompletionAction, ReplayResult } from '../engine/replayConstruction' import { getAllPoints, getPoint } from '../engine/constructionState' import { screenToWorld2D, worldToScreen2D } from '../../shared/coordinateConversions' import { replayConstruction } from '../engine/replayConstruction' import { solveInverseKinematics, solveInverse, createSolverState, type InverseSolverState, type ForwardFn, } from '../engine/inverseSolver' import { RECIPE_REGISTRY } from '../engine/recipe/definitions/registry' import { evaluateRecipe } from '../engine/recipe/evaluate' import { computeInfluence, constrainedDragStep, isSubJacobianRankDeficient, type InfluenceResult, } from '../engine/jacobianInfluence' import type { InfluenceHighlightState, MotionTrailState, BreakFreeFlash, } from '../render/renderInfluenceHighlight' import { recordTrailPosition, clearTrail, TENSION_START_RADIUS, BREAK_FREE_RADIUS, TENSION_DAMPEN, } from '../render/renderInfluenceHighlight' import type { Pt } from '../engine/recipe/types' /** Hit radius for draggable points (screen pixels) */ const HIT_RADIUS_MOUSE = 30 const HIT_RADIUS_TOUCH = 44 interface UseDragGivenPointsOptions { canvasRef: React.RefObject<HTMLCanvasElement | null> propositionRef: React.MutableRefObject<PropositionDef> constructionRef: React.MutableRefObject<ConstructionState> factStoreRef: React.MutableRefObject<FactStore> proofFactsRef: React.MutableRefObject<ProofFact[]> viewportRef: React.MutableRefObject<EuclidViewportState> isCompleteRef: React.MutableRefObject<boolean> activeToolRef: React.MutableRefObject<ActiveTool> needsDrawRef: React.MutableRefObject<boolean> pointerCapturedRef: React.MutableRefObject<boolean> candidatesRef: React.MutableRefObject<IntersectionCandidate[]> postCompletionActionsRef: React.MutableRefObject<PostCompletionAction[]> /** Per-step data (e.g. user-chosen extend distances) for replay */ stepDataRef?: React.MutableRefObject<Map<number, Record<string, unknown>>> /** When true, drag interactions are suppressed (e.g. during correction animations) */ interactionLockedRef?: React.MutableRefObject<boolean> /** Whether we're in free-form playground mode (no recipe) */ playgroundModeRef?: React.MutableRefObject<boolean | undefined> /** Whether full solver mode is active (vs constrained single-point drag) */ solverModeRef?: React.MutableRefObject<boolean> /** Ref updated with the hovered derived point ID (for influence highlight rendering) */ hoveredDerivedPointIdRef?: React.MutableRefObject<string | null> /** Ref updated with the most influential given point ID (for influence highlight rendering) */ influentialGivenPointIdRef?: React.MutableRefObject<string | null> /** Influence highlight state ref — used to set subJacobian for preview arrow */ influenceHighlightStateRef?: React.MutableRefObject<InfluenceHighlightState> /** Motion trail state ref — used to record given point positions during constrained drag */ motionTrailStateRef?: React.MutableRefObject<MotionTrailState> /** Break-free flash ref — set when constraint snaps during drag */ breakFreeFlashRef?: React.MutableRefObject<BreakFreeFlash | null> /** Called when construction state is replaced during drag */ onReplayResult: (result: ReplayResult) => void /** Called once when a drag gesture starts on a given point */ onDragStart?: (pointId: string) => void /** Ref updated with the currently dragged point ID (null when not dragging) */ dragPointIdRef?: React.MutableRefObject<string | null> /** Called when a drag gesture ends */ onDragEnd?: () => void } /** * Post-completion drag interaction for all construction points. * * - Given/free/extend points: direct position update (existing behavior) * - Derived points (intersections, produced, macro outputs): inverse solver * finds given point positions that place the dragged point at the cursor. * * The inverse solver uses Levenberg-Marquardt with the recipe evaluator as * its forward model, warm-started across frames for real-time performance. */ export function useDragGivenPoints({ canvasRef, propositionRef, constructionRef, factStoreRef, proofFactsRef, viewportRef, isCompleteRef, activeToolRef, needsDrawRef, pointerCapturedRef, candidatesRef, postCompletionActionsRef, stepDataRef, interactionLockedRef, playgroundModeRef, solverModeRef, hoveredDerivedPointIdRef, influentialGivenPointIdRef, influenceHighlightStateRef, motionTrailStateRef, breakFreeFlashRef, onReplayResult, onDragStart, dragPointIdRef, onDragEnd, }: UseDragGivenPointsOptions): void { const getCanvasRect = useCallback(() => { return canvasRef.current?.getBoundingClientRect() }, [canvasRef]) useEffect(() => { const canvas = canvasRef.current if (!canvas) return let dragPointId: string | null = null let dragPointOrigin: ConstructionPoint['origin'] | null = null let hoveredDraggableId: string | null = null /** Solver state persisted across frames within a single drag gesture */ let solverState: InverseSolverState | null = null /** Influence result locked at drag start for constrained drag */ let dragInfluence: InfluenceResult | null = null /** Previous world position for computing drag deltas in constrained mode */ let prevDragWorld: { x: number; y: number } | null = null /** Frame counter for periodic sub-Jacobian refresh during constrained drag */ let constrainedDragFrameCount = 0 /** RAF handle for snap-to-cursor animation at drag start */ let snapAnimId: number | null = null /** Click-time cursor world position locked in by the snap-to-cursor anim; * used to seed prevDragWorld when the user cancels the snap by moving. */ let snapTargetWorld: { x: number; y: number } | null = null /** Whether the constraint has broken free during this drag gesture (sticky) */ let breakFree = false /** Eased transition from constrained pose → solver pose at the moment of break-free. * While active, the dispatcher routes nothing — the RAF loop owns construction state. */ let breakFreeTransition: { kind: 'recipe' | 'playground' /** Input positions at the moment of break-free (ordered to match toPositions). */ fromPositions: Pt[] /** Solver-target input positions, computed once at break-free. */ toPositions: Pt[] /** For playground mode, the point IDs corresponding to each position slot. */ pointIds?: string[] startTime: number durationMs: number } | null = null let breakFreeTransitionId: number | null = null /** Last cursor world position seen by solver path — used to detect "stuck" */ let prevCursorWorldSolver: { x: number; y: number } | null = null /** Consecutive frames where solver didn't move target despite cursor movement */ let solverStuckCount = 0 /** Consecutive frames where solveInverse exhausted its iterations without * progress (post-call lambda saturated near the per-call cap). Logged in * the per-frame diagnostic only — useful for verifying that the * one-sided-diff + backtracking fixes keep this counter low. */ let solverSaturatedCount = 0 // ── Diagnostic logging (filter console by "[stuck-debug]") ── // Per-frame logs are throttled to one every 250ms; discrete events // (drag-start, guard-fired, break-free, solver-revert, etc.) always fire. let lastFrameLogMs = 0 function logFrame(data: object): void { const now = performance.now() if (now - lastFrameLogMs < 250) return lastFrameLogMs = now console.log('[stuck-debug] frame', data) } function logEvent(name: string, data?: object): void { console.log(`[stuck-debug] ${name}`, data ?? '') } function toWorld(sx: number, sy: number, cw: number, ch: number) { const v = viewportRef.current return screenToWorld2D( sx, sy, v.center.x, v.center.y, v.pixelsPerUnit, v.pixelsPerUnit, cw, ch ) } function getCSSSize() { const dpr = window.devicePixelRatio || 1 return { w: canvas!.width / dpr, h: canvas!.height / dpr, } } /** * Hit-test ALL construction points — given, free, extend, AND derived. * Returns the closest point within the hit radius, with priority: * given/free/extend points win ties over derived points (so direct * dragging is preferred when a given point overlaps a derived one). */ function hitTestAllPoints( screenX: number, screenY: number, isTouch: boolean ): ConstructionPoint | null { const prop = propositionRef.current const threshold = isTouch ? HIT_RADIUS_TOUCH : HIT_RADIUS_MOUSE const state = constructionRef.current const viewport = viewportRef.current const { w, h } = getCSSSize() const draggableSet = new Set(prop.draggablePointIds ?? []) const recipe = RECIPE_REGISTRY[prop.id] let best: ConstructionPoint | null = null let bestDist = Infinity let bestIsDirect = false // true if best is a given/free/extend point const isPlayground = !!playgroundModeRef?.current for (const pt of getAllPoints(state)) { const isDirect = draggableSet.has(pt.id) || pt.origin === 'free' || pt.origin === 'extend' const isDerived = !isDirect && (recipe != null || isPlayground) if (!isDirect && !isDerived) continue const s = worldToScreen2D( pt.x, pt.y, viewport.center.x, viewport.center.y, viewport.pixelsPerUnit, viewport.pixelsPerUnit, w, h ) const dx = screenX - s.x const dy = screenY - s.y const dist = Math.sqrt(dx * dx + dy * dy) if (dist >= threshold) continue // Direct points take priority over derived points at equal distance if (dist < bestDist || (dist === bestDist && isDirect && !bestIsDirect)) { best = pt bestDist = dist bestIsDirect = isDirect } } return best } function collectCurrentPositions(): Map<string, { x: number; y: number }> { const positions = new Map<string, { x: number; y: number }>() for (const el of constructionRef.current.elements) { if (el.kind === 'point' && el.origin === 'given') { positions.set(el.id, { x: el.x, y: el.y }) } } return positions } /** * Collect current input positions ordered by recipe input slots. * Returns null if the recipe or any input point is missing. */ function collectRecipeInputPositions(): Pt[] | null { const prop = propositionRef.current const recipe = RECIPE_REGISTRY[prop.id] if (!recipe) return null const positions: Pt[] = [] for (const slot of recipe.inputSlots) { const ptId = `pt-${slot.ref}` const pt = getPoint(constructionRef.current, ptId) if (!pt) return null positions.push({ x: pt.x, y: pt.y }) } return positions } /** * Convert a construction point ID ('pt-C') to a recipe ref ('C'). */ function pointIdToRef(pointId: string): string { return pointId.startsWith('pt-') ? pointId.slice(3) : pointId } /** * Build a forward function and collect input positions for influence * computation. Works for both recipe and playground modes. * Returns null if the construction can't be analyzed. */ function buildInfluenceContext(targetPointId: string): { forward: ForwardFn inputPositions: Pt[] pointIds: string[] } | null { const prop = propositionRef.current const recipe = RECIPE_REGISTRY[prop.id] const isPlayground = !!playgroundModeRef?.current if (isPlayground || !recipe) { // Playground: inputs are given + free points const inputs = collectPlaygroundInputPositions() if (!inputs) return null const forward = buildPlaygroundForward(targetPointId, inputs.pointIds) return { forward, inputPositions: inputs.positions, pointIds: inputs.pointIds } } // Recipe mode const inputPositions = collectRecipeInputPositions() if (!inputPositions) return null const targetRef = pointIdToRef(targetPointId) const pointIds = recipe.inputSlots.map((s) => `pt-${s.ref}`) // Check if this is a recipe point or post-completion point const isRecipePoint = recipe.inputSlots.some((s) => s.ref === targetRef) || recipe.ops.some((op) => { if (op.kind === 'intersection') return op.output === targetRef if (op.kind === 'produce') return op.output === targetRef if (op.kind === 'apply') return Object.values(op.outputs).includes(targetRef) return false }) if (isRecipePoint) { const forward: ForwardFn = (positions) => { const trace = evaluateRecipe(recipe, positions, RECIPE_REGISTRY) return trace?.pointMap.get(targetRef) ?? null } return { forward, inputPositions, pointIds } } // Post-completion point: use replay forward const forward = buildReplayForward(targetPointId) return { forward, inputPositions, pointIds } } /** * Compute influence info for a derived point. Returns null if the point * has no valid (non-rank-deficient) controlling given. */ function tryComputeInfluence(derivedPointId: string): { bestPointId: string subJacobian: [number, number, number, number] } | null { const ctx = buildInfluenceContext(derivedPointId) if (!ctx) return null const influence = computeInfluence(ctx.forward, ctx.inputPositions, ctx.pointIds) if (!influence || !influence.bestPointId) return null if (isSubJacobianRankDeficient(influence.subJacobian)) return null return { bestPointId: influence.bestPointId, subJacobian: influence.subJacobian } } /** * Compute influence for a derived point and update the hover highlight * refs (drives the ring + preview arrow + dashed line on hover). */ function updateInfluenceHighlight(derivedPointId: string | null): void { const clear = () => { if (hoveredDerivedPointIdRef) hoveredDerivedPointIdRef.current = null if (influentialGivenPointIdRef) influentialGivenPointIdRef.current = null if (influenceHighlightStateRef) influenceHighlightStateRef.current.subJacobian = null } if (!derivedPointId) { clear() return } const inf = tryComputeInfluence(derivedPointId) if (!inf) { clear() return } if (hoveredDerivedPointIdRef) hoveredDerivedPointIdRef.current = derivedPointId if (influentialGivenPointIdRef) influentialGivenPointIdRef.current = inf.bestPointId if (influenceHighlightStateRef) { influenceHighlightStateRef.current.subJacobian = inf.subJacobian } needsDrawRef.current = true } /** * Track the nearest derived-with-valid-influence point to the cursor * (regardless of hit-test). Drives the background constraint-response * field: as the cursor approaches a point, the field fades in via * proximity falloff; as it moves away, the field fades out. Decoupling * from hover hit-test removes the hard threshold the user observed. * * Caches influence results per derived point so we don't recompute on * every pointer move. Cache is cleared when the construction changes * (handled at handlePointerDown / handleDragEnd via clearFieldCache). */ const fieldInfluenceCache = new Map< string, { bestPointId: string; subJacobian: [number, number, number, number] } | null >() function clearFieldCache(): void { fieldInfluenceCache.clear() } function getCachedInfluence( derivedPointId: string ): { bestPointId: string; subJacobian: [number, number, number, number] } | null { if (fieldInfluenceCache.has(derivedPointId)) { return fieldInfluenceCache.get(derivedPointId) ?? null } const inf = tryComputeInfluence(derivedPointId) fieldInfluenceCache.set(derivedPointId, inf) return inf } function updateFieldTarget(screenX: number, screenY: number): void { if (!influenceHighlightStateRef) return const state = constructionRef.current const viewport = viewportRef.current const { w, h } = getCSSSize() const recipe = RECIPE_REGISTRY[propositionRef.current.id] const isPlayground = !!playgroundModeRef?.current // Find all derived points with valid (non-rank-deficient) influence, // compute screen-space distance to cursor. We render the closest few // simultaneously, each with its own proximity factor, so as the cursor // moves between two derived points their fields naturally crossfade — // no hard switch. const PROX_EPSILON = 0.05 // pre-filter radius: prox = R²/(R²+d²) > eps ⇔ d < R·√(1/eps − 1). // R = 220 px (must match PROXIMITY_HALF_RADIUS_PX in the renderer). const maxD = 220 * Math.sqrt(1 / PROX_EPSILON - 1) const maxD2 = maxD * maxD type Candidate = { pt: ReturnType<typeof getAllPoints>[number] d2: number inf: { bestPointId: string; subJacobian: [number, number, number, number] } } const candidates: Candidate[] = [] for (const pt of getAllPoints(state)) { if (!isDerivedOrigin(pt.origin)) continue if (!recipe && !isPlayground) continue const s = worldToScreen2D( pt.x, pt.y, viewport.center.x, viewport.center.y, viewport.pixelsPerUnit, viewport.pixelsPerUnit, w, h ) const dx = screenX - s.x const dy = screenY - s.y const d2 = dx * dx + dy * dy if (d2 > maxD2) continue const inf = getCachedInfluence(pt.id) if (!inf) continue candidates.push({ pt, d2, inf }) } // Sort by ascending distance, keep at most MAX_TARGETS to bound LIC // cost. 3 is plenty for Voronoi junctions where multiple points are // near-equidistant; further targets contribute negligibly anyway. const MAX_TARGETS = 3 candidates.sort((a, b) => a.d2 - b.d2) const top = candidates.slice(0, MAX_TARGETS) const hl = influenceHighlightStateRef.current const next = top.map((c) => ({ derivedPointId: c.pt.id, givenPointId: c.inf.bestPointId, subJacobian: c.inf.subJacobian, })) let changed = next.length !== hl.fieldTargets.length if (!changed) { for (let i = 0; i < next.length; i++) { const a = hl.fieldTargets[i] const b = next[i] if ( a.derivedPointId !== b.derivedPointId || a.givenPointId !== b.givenPointId || a.subJacobian !== b.subJacobian ) { changed = true break } } } if (changed) { hl.fieldTargets = next needsDrawRef.current = true } } /** * Apply solved input positions to the construction via replay. */ function applyInverseSolution(solvedPositions: Pt[]): void { const prop = propositionRef.current const recipe = RECIPE_REGISTRY[prop.id] if (!recipe) return // Build positions map from solved input positions const positions = new Map<string, { x: number; y: number }>() for (let i = 0; i < recipe.inputSlots.length; i++) { const ptId = `pt-${recipe.inputSlots[i].ref}` positions.set(ptId, solvedPositions[i]) } // Compute fresh given elements const computeFn = prop.computeGivenElements let givenElements: ConstructionElement[] if (computeFn) { givenElements = computeFn(positions) } else { givenElements = prop.givenElements.map((el) => { if (el.kind === 'point' && positions.has(el.id)) { const pos = positions.get(el.id)! return { ...el, x: pos.x, y: pos.y } } return el }) } // Replay the full construction const actions = postCompletionActionsRef.current const result = replayConstruction( givenElements, prop.steps, prop, actions, stepDataRef?.current ) constructionRef.current = result.state factStoreRef.current = result.factStore mergeProofFacts(factStoreRef.current, proofFactsRef.current) candidatesRef.current = result.candidates onReplayResult(result) needsDrawRef.current = true } /** * Smoothly animate the derived point toward the cursor at the start * of a constrained drag. Uses eased constrained drag steps over ~200ms * so the point "magnetically" snaps to the cursor position. */ function startSnapAnimation(pointId: string, targetWorld: { x: number; y: number }): void { if (snapAnimId != null) { cancelAnimationFrame(snapAnimId) snapAnimId = null } snapTargetWorld = targetWorld const SNAP_DURATION_MS = 200 const SNAP_STEPS = 12 const startTime = performance.now() let step = 0 function snapFrame() { snapAnimId = null // Bail if drag ended, point changed, or break-free has fired (the // solver path now owns the construction state — don't fight it). if (dragPointId !== pointId || !dragInfluence || breakFree) { snapTargetWorld = null return } const elapsed = performance.now() - startTime const t = Math.min(1, elapsed / SNAP_DURATION_MS) step++ // Get current derived point position const derivedPt = getPoint(constructionRef.current, pointId) if (!derivedPt) return // Vector from current derived position to cursor target const dxWorld = targetWorld.x - derivedPt.x const dyWorld = targetWorld.y - derivedPt.y const dist = Math.sqrt(dxWorld * dxWorld + dyWorld * dyWorld) // Close enough or done — stop if (dist < 0.001 || step >= SNAP_STEPS) { // Set prevDragWorld so subsequent pointer moves work correctly prevDragWorld = targetWorld snapTargetWorld = null return } // Ease-out fraction: move a larger proportion each frame const fraction = 1 - (1 - t) ** 2 const stepDx = dxWorld * fraction const stepDy = dyWorld * fraction // Refresh sub-Jacobian periodically if (step % 4 === 0) { const ctx = buildInfluenceContext(pointId) if (ctx) { const fresh = computeInfluence(ctx.forward, ctx.inputPositions, ctx.pointIds) if (fresh && fresh.bestInputIndex === dragInfluence!.bestInputIndex) { dragInfluence!.subJacobian = fresh.subJacobian } } } const givenPointId = dragInfluence!.bestPointId if (!givenPointId) return const givenPt = getPoint(constructionRef.current, givenPointId) if (!givenPt) return const newGivenPos = constrainedDragStep( { x: givenPt.x, y: givenPt.y }, { x: stepDx, y: stepDy }, dragInfluence!.subJacobian ) // Treat any near-singular result as degenerate. constrainedDragStep // only returns null when |det| < 1e-12, but for rank-1 sub-Jacobians // (e.g. line-line intersection driven by one corner) det can be // ~1e-9 with finite-difference noise — small enough that 1/det // still makes the corner fly to ~1e9 units. Reject by screen-px // displacement of the given, which is what the user actually sees. const SNAP_MAX_GIVEN_MOVE_PX = 200 const vpForCheck = viewportRef.current const givenMoveDistPx = newGivenPos ? Math.sqrt( ((newGivenPos.x - givenPt.x) * vpForCheck.pixelsPerUnit) ** 2 + ((newGivenPos.y - givenPt.y) * vpForCheck.pixelsPerUnit) ** 2 ) : Infinity if (!newGivenPos || givenMoveDistPx > SNAP_MAX_GIVEN_MOVE_PX) { logEvent('snap-degenerate-breakfree', { givenMoveDistPx: givenMoveDistPx.toFixed(1), }) const { w: sw, h: sh } = getCSSSize() const vp = viewportRef.current const dPt = getPoint(constructionRef.current, pointId) if (dPt) { const dScreen = worldToScreen2D( dPt.x, dPt.y, vp.center.x, vp.center.y, vp.pixelsPerUnit, vp.pixelsPerUnit, sw, sh ) triggerBreakFree(targetWorld, dScreen, vp, sw, sh) } else { breakFree = true handleDerivedPointDragSolver(targetWorld) } prevDragWorld = targetWorld snapTargetWorld = null return } // Apply the movement const prop = propositionRef.current const prevActions = postCompletionActionsRef.current if (givenPt.origin === 'free') { postCompletionActionsRef.current = postCompletionActionsRef.current.map((a) => a.type === 'free-point' && a.id === givenPointId ? { ...a, x: newGivenPos.x, y: newGivenPos.y } : a ) } const positions = collectCurrentPositions() if (givenPt.origin === 'given') { positions.set(givenPointId, newGivenPos) } const computeFn = prop.computeGivenElements let givenElements: ConstructionElement[] if (computeFn) { givenElements = computeFn(positions) } else { givenElements = prop.givenElements.map((el) => { if (el.kind === 'point' && positions.has(el.id)) { const pos = positions.get(el.id)! return { ...el, x: pos.x, y: pos.y } } return el }) } const actions = postCompletionActionsRef.current const result = replayConstruction( givenElements, prop.steps, prop, actions, stepDataRef?.current ) // Guard: if this snap step would destroy the dragged point, break // free to solver — retrying on the next snap frame would just fail // the same way (see handleDerivedPointDragConstrained). if (!getPoint(result.state, pointId)) { postCompletionActionsRef.current = prevActions const dPt = getPoint(constructionRef.current, pointId) if (dPt) { const { w: sw, h: sh } = getCSSSize() const vp = viewportRef.current const dScreen = worldToScreen2D( dPt.x, dPt.y, vp.center.x, vp.center.y, vp.pixelsPerUnit, vp.pixelsPerUnit, sw, sh ) triggerBreakFree(targetWorld, dScreen, vp, sw, sh) } else { breakFree = true handleDerivedPointDragSolver(targetWorld) } prevDragWorld = targetWorld snapTargetWorld = null return } constructionRef.current = result.state factStoreRef.current = result.factStore mergeProofFacts(factStoreRef.current, proofFactsRef.current) candidatesRef.current = result.candidates onReplayResult(result) needsDrawRef.current = true // Record trail during snap if (motionTrailStateRef) { const updatedGivenPt = getPoint(result.state, givenPointId) if (updatedGivenPt) { const { w, h } = getCSSSize() const v = viewportRef.current const screen = worldToScreen2D( updatedGivenPt.x, updatedGivenPt.y, v.center.x, v.center.y, v.pixelsPerUnit, v.pixelsPerUnit, w, h ) recordTrailPosition(motionTrailStateRef.current, givenPointId, screen.x, screen.y) } } if (t < 1) { snapAnimId = requestAnimationFrame(snapFrame) } else { prevDragWorld = targetWorld snapTargetWorld = null } } snapAnimId = requestAnimationFrame(snapFrame) } function handlePointerDown(e: PointerEvent) { if (!isCompleteRef.current || activeToolRef.current !== 'move') return if (pointerCapturedRef.current) return if (interactionLockedRef?.current) return const rect = getCanvasRect() if (!rect) return const sx = e.clientX - rect.left const sy = e.clientY - rect.top const isTouch = e.pointerType === 'touch' const hit = hitTestAllPoints(sx, sy, isTouch) if (hit) { e.stopPropagation() e.preventDefault() dragPointId = hit.id dragPointOrigin = hit.origin if (dragPointIdRef) dragPointIdRef.current = hit.id pointerCapturedRef.current = true canvas!.style.cursor = 'grabbing' needsDrawRef.current = true // Initialize drag state for derived point drags if (isDerivedOrigin(hit.origin)) { solverState = createSolverState() // Compute influence for constrained drag mode const infCtx = buildInfluenceContext(hit.id) if (infCtx) { dragInfluence = computeInfluence(infCtx.forward, infCtx.inputPositions, infCtx.pointIds) } constrainedDragFrameCount = 0 // If the most-influential given's sub-Jacobian can only move the // derived along a 1-D locus (canonical case: target is the // intersection of two lines, perturbing one corner just slides // the intersection along the other line), constrained drag will // either jam or fly to infinity. Flip break-free immediately so // the rest of the gesture goes straight to the LM solver — which // can deploy all input DOFs together. if (dragInfluence && isSubJacobianRankDeficient(dragInfluence.subJacobian)) { breakFree = true } logEvent('drag-start', { id: hit.id, origin: hit.origin, bestPointId: dragInfluence?.bestPointId, subJ: dragInfluence?.subJacobian.map((n) => n.toFixed(3)).join(','), breakFreeAtStart: breakFree, }) // Start snap-to-cursor animation in constrained mode const useSolver = solverModeRef?.current ?? false if (!useSolver && !breakFree && dragInfluence) { const { w, h } = getCSSSize() const clickWorld = toWorld(sx, sy, w, h) startSnapAnimation(hit.id, clickWorld) } // Keep the influence highlight (ring on the given, dashed line, // rubber-band cue) visible during constrained drag so the user can // see the tension build as they pull the cursor away. In solver or // break-free modes there is no single "controlling" given, so clear. if (!useSolver && !breakFree && dragInfluence && dragInfluence.bestPointId) { if (hoveredDerivedPointIdRef) hoveredDerivedPointIdRef.current = hit.id if (influentialGivenPointIdRef) influentialGivenPointIdRef.current = dragInfluence.bestPointId } else { if (hoveredDerivedPointIdRef) hoveredDerivedPointIdRef.current = null if (influentialGivenPointIdRef) influentialGivenPointIdRef.current = null } } else { solverState = null dragInfluence = null // Direct drag of a given/free/extend point — no influence highlight. if (hoveredDerivedPointIdRef) hoveredDerivedPointIdRef.current = null if (influentialGivenPointIdRef) influentialGivenPointIdRef.current = null } prevDragWorld = null onDragStart?.(hit.id) } } function handlePointerMove(e: PointerEvent) { if (!isCompleteRef.current || activeToolRef.current !== 'move') return const prop = propositionRef.current const rect = getCanvasRect() if (!rect) return const sx = e.clientX - rect.left const sy = e.clientY - rect.top const { w, h } = getCSSSize() const isTouch = e.pointerType === 'touch' if (dragPointId) { // Dragging — update position and replay construction e.stopPropagation() e.preventDefault() const world = toWorld(sx, sy, w, h) // If the drag-start snap-to-cursor animation is still running, the // user has taken control. Cancel the snap and seed prevDragWorld // with its click target so the first constrained-drag delta is // (cursor − click), matching what the user perceives as their drag. if (snapAnimId != null) { cancelAnimationFrame(snapAnimId) snapAnimId = null if (snapTargetWorld) prevDragWorld = snapTargetWorld snapTargetWorld = null } // Route to the appropriate drag handler based on point origin if (dragPointOrigin && isDerivedOrigin(dragPointOrigin)) { // ── Inverse solver path: derived point ── handleDerivedPointDrag(world) } else { // ── Direct path: given/free/extend point ── handleDirectPointDrag(world, prop) } } else { // Not dragging — update cursor and influence highlight based on hover const hit = hitTestAllPoints(sx, sy, isTouch) const newHoveredId = hit?.id ?? null if (newHoveredId !== hoveredDraggableId) { hoveredDraggableId = newHoveredId if (hoveredDraggableId) { canvas!.style.cursor = 'grab' } else { canvas!.style.cursor = '' } // Update influence highlight for derived points if (hit && isDerivedOrigin(hit.origin)) { updateInfluenceHighlight(hit.id) } else { updateInfluenceHighlight(null) } } // Track nearest-derived for the field background regardless of // hit-test, so the field fades smoothly with cursor proximity rather // than popping in at the hit-test boundary. updateFieldTarget(sx, sy) } } /** * Build a replay-based forward function for post-completion points. * This replays the full construction (recipe steps + post-completion actions) * and looks up the target point in the resulting state. */ function buildReplayForward(targetPointId: string): ForwardFn { const prop = propositionRef.current const recipe = RECIPE_REGISTRY[prop.id] if (!recipe) return () => null return (inputPositions: Pt[]) => { // Map solved input positions to given element positions const positions = new Map<string, { x: number; y: number }>() for (let i = 0; i < recipe.inputSlots.length; i++) { positions.set(`pt-${recipe.inputSlots[i].ref}`, inputPositions[i]) } // Compute given elements const computeFn = prop.computeGivenElements let givenElements: ConstructionElement[] if (computeFn) { givenElements = computeFn(positions) } else { givenElements = prop.givenElements.map((el) => { if (el.kind === 'point' && positions.has(el.id)) { const pos = positions.get(el.id)! return { ...el, x: pos.x, y: pos.y } } return el }) } // Replay with post-completion actions const result = replayConstruction( givenElements, prop.steps, prop, postCompletionActionsRef.current, stepDataRef?.current ) // Find the target point in the replayed state const pt = getPoint(result.state, targetPointId) return pt ? { x: pt.x, y: pt.y } : null } } /** * Collect all given + free point positions as solver inputs for playground mode. * Returns { positions, pointIds } where pointIds tracks which point each position maps to. */ function collectPlaygroundInputPositions(): { positions: Pt[]; pointIds: string[] } | null { const positions: Pt[] = [] const pointIds: string[] = [] // Given points for (const el of constructionRef.current.elements) { if (el.kind === 'point' && el.origin === 'given') { positions.push({ x: el.x, y: el.y }) pointIds.push(el.id) } } // Free points (from post-completion actions) for (const action of postCompletionActionsRef.current) { if (action.type === 'free-point') { positions.push({ x: action.x, y: action.y }) pointIds.push(action.id) } } return positions.length > 0 ? { positions, pointIds } : null } /** * Build a replay-based forward function for playground mode. * Maps given + free point positions through a full replay to find the target. */ function buildPlaygroundForward(targetPointId: string, pointIds: string[]): ForwardFn { const prop = propositionRef.current return (inputPositions: Pt[]) => { // Build given elements with updated positions const givenPositions = new Map<string, { x: number; y: number }>() const freePositions = new Map<string, { x: number; y: number }>() for (let i = 0; i < pointIds.length; i++) { const pt = getPoint(constructionRef.current, pointIds[i]) if (pt?.origin === 'given') { givenPositions.set(pointIds[i], inputPositions[i]) } else { freePositions.set(pointIds[i], inputPositions[i]) } } const givenElements = prop.givenElements.map((el) => { if (el.kind === 'point' && givenPositions.has(el.id)) { const pos = givenPositions.get(el.id)! return { ...el, x: pos.x, y: pos.y } } return el }) // Update free-point actions with solved positions const actions = postCompletionActionsRef.current.map((a) => { if (a.type === 'free-point' && freePositions.has(a.id)) { const pos = freePositions.get(a.id)! return { ...a, x: pos.x, y: pos.y } } return a }) const result = replayConstruction( givenElements, prop.steps, prop, actions, stepDataRef?.current ) const pt = getPoint(result.state, targetPointId) return pt ? { x: pt.x, y: pt.y } : null } } /** * Apply solved input positions in playground mode (given + free points). */ function applyPlaygroundSolution(solvedPositions: Pt[], pointIds: string[]): void { const prop = propositionRef.current // Build given element positions const positions = new Map<string, { x: number; y: number }>() for (let i = 0; i < pointIds.length; i++) { const pt = getPoint(constructionRef.current, pointIds[i]) if (pt?.origin === 'given') { positions.set(pointIds[i], solvedPositions[i]) } } // Update free-point actions const actions = postCompletionActionsRef.current.map((a) => { if (a.type === 'free-point') { const idx = pointIds.indexOf(a.id) if (idx >= 0) return { ...a, x: solvedPositions[idx].x, y: solvedPositions[idx].y } } return a }) postCompletionActionsRef.current = actions const computeFn = prop.computeGivenElements let givenElements: ConstructionElement[] if (computeFn) { givenElements = computeFn(positions) } else { givenElements = prop.givenElements.map((el) => { if (el.kind === 'point' && positions.has(el.id)) { const pos = positions.get(el.id)! return { ...el, x: pos.x, y: pos.y } } return el }) } const result = replayConstruction( givenElements, prop.steps, prop, actions, stepDataRef?.current ) constructionRef.current = result.state factStoreRef.current = result.factStore mergeProofFacts(factStoreRef.current, proofFactsRef.current) candidatesRef.current = result.candidates onReplayResult(result) needsDrawRef.current = true } /** * Handle drag of a derived point using FULL SOLVER mode. * The derived point tracks the cursor exactly. */ function handleDerivedPointDragSolver(world: { x: number; y: number }): void { if (!dragPointId || !solverState) return const prop = propositionRef.current const recipe = RECIPE_REGISTRY[prop.id] const isPlayground = !!playgroundModeRef?.current // Cap warm-started lambda. solveInverse adapts lambda within its // 5-iteration call (growing 4× on null forward, 2× on residual not // decreasing, 0.5× on improvement). Warm-starting across frames is // useful in the converged regime (lambda settles around 1e-8). But // when the cursor enters a topologically unreachable region, every // iteration fails and lambda grows by ~1024× per frame. A few stuck // frames take it to 1e+30+, after which any future step is too // damped to recover even when the cursor returns to reachable space. // Capping keeps the converged regime fast (1e-3 is a small step from // 1e-8) while preventing the runaway. solverState.lambda = Math.min(solverState.lambda, 1e-3) // Snapshot current state so we can revert if the solver destroys the target point const prevState = constructionRef.current const prevFactStore = factStoreRef.current const prevCandidates = candidatesRef.current const prevActions = postCompletionActionsRef.current const prevDerivedPt = getPoint(prevState, dragPointId) if (isPlayground || !recipe) { const inputs = collectPlaygroundInputPositions() if (!inputs) return const forward = buildPlaygroundForward(dragPointId, inputs.pointIds) const solveResult = solveInverse(forward, inputs.positions, world, solverState) applyPlaygroundSolution(solveResult.inputPositions, inputs.pointIds) } else { const currentInputPositions = collectRecipeInputPositions() if (!currentInputPositions) return const targetRef = pointIdToRef(dragPointId) const isRecipePoint = recipe.inputSlots.some((s) => s.ref === targetRef) || recipe.ops.some((op) => { if (op.kind === 'intersection') return op.output === targetRef if (op.kind === 'produce') return op.output === targetRef if (op.kind === 'apply') return Object.values(op.outputs).includes(targetRef) return false }) let solveResult if (isRecipePoint) { solveResult = solveInverseKinematics( recipe, currentInputPositions, targetRef, world, RECIPE_REGISTRY, solverState ) } else { const forward = buildReplayForward(dragPointId) solveResult = solveInverse(forward, currentInputPositions, world, solverState) } applyInverseSolution(solveResult.inputPositions) } // Track whether this solveInverse call exhausted its iteration budget // without making progress (lambda saturated near its per-call ceiling // of 1e-3 × 4^5 ≈ 1). Logged for diagnostics; behavior is "block": // when saturated, solveInverse returns its starting params unchanged // (bestParams = iter 0 params if no candidate ever improved residual), // so the apply call is a no-op and the construction stays where it is. if (solverState.lambda > 0.5) solverSaturatedCount++ else solverSaturatedCount = 0 // ── Guard: if the solver produced a degenerate result, revert ── const targetPt = getPoint(constructionRef.current, dragPointId) if (!targetPt) { logEvent('solver-revert-no-target', { cursorWorld: { x: world.x.toFixed(3), y: world.y.toFixed(3) }, prevDerived: prevDerivedPt ? { x: prevDerivedPt.x.toFixed(3), y: prevDerivedPt.y.toFixed(3) } : null, }) constructionRef.current = prevState factStoreRef.current = prevFactStore candidatesRef.current = prevCandidates postCompletionActionsRef.current = prevActions needsDrawRef.current = true } else { const v2 = viewportRef.current const errFromCursorPx = Math.sqrt( ((targetPt.x - world.x) * v2.pixelsPerUnit) ** 2 + ((targetPt.y - world.y) * v2.pixelsPerUnit) ** 2 ) const targetMovePx = prevDerivedPt ? Math.sqrt( ((targetPt.x - prevDerivedPt.x) * v2.pixelsPerUnit) ** 2 + ((targetPt.y - prevDerivedPt.y) * v2.pixelsPerUnit) ** 2 ) : 0 // Track cursor velocity for stuck detection (logging only — the // warm-start cap above is what actually prevents the lambda trap). const cursorMovePx = prevCursorWorldSolver ? Math.sqrt( ((world.x - prevCursorWorldSolver.x) * v2.pixelsPerUnit) ** 2 + ((world.y - prevCursorWorldSolver.y) * v2.pixelsPerUnit) ** 2 ) : 0 prevCursorWorldSolver = world const isStuck = targetMovePx < 1 && cursorMovePx > 3 && errFromCursorPx > 5 if (isStuck) solverStuckCount++ else if (targetMovePx >= 1) solverStuckCount = 0 logFrame({ mode: 'solver', targetMovePx: targetMovePx.toFixed(1), cursorMovePx: cursorMovePx.toFixed(0), errFromCursorPx: errFromCursorPx.toFixed(0), lambda: solverState?.lambda.toExponential(1), satCount: solverSaturatedCount, }) // Check if any given/free point moved excessively far const MAX_POINT_MOVE_PX = 500 const v = viewportRef.current let degenerate = false for (const el of constructionRef.current.elements) { if (el.kind !== 'point') continue if (el.origin !== 'given' && el.origin !== 'free') continue const prevPt = getPoint(prevState, el.id) if (!prevPt) continue const movePx = Math.sqrt( ((el.x - prevPt.x) * v.pixelsPerUnit) ** 2 + ((el.y - prevPt.y) * v.pixelsPerUnit) ** 2 ) if (movePx > MAX_POINT_MOVE_PX) { logEvent('solver-revert-excessive-move', { pointId: el.id, movePx: movePx.toFixed(0), }) degenerate = true break } } if (degenerate) { constructionRef.current = prevState factStoreRef.current = prevFactStore candidatesRef.current = prevCandidates postCompletionActionsRef.current = prevActions needsDrawRef.current = true } } } /** * Handle drag of a derived point using CONSTRAINED mode. * Only moves a single given point — the derived point follows * deterministically but doesn't perfectly track the cursor, * revealing the construction's geometric constraints. */ /** * One frame of the break-free → solver-pose transition. * Lerps input positions with easeOutCubic and replays the construction. * Continues to RAF until t reaches 1, then clears the transition so the * dispatcher resumes normal solver-mode handling on the next pointer move. */ function stepBreakFreeTransition(): void { breakFreeTransitionId = null if (!breakFreeTransition || !dragPointId) { breakFreeTransition = null return } const elapsed = performance.now() - breakFreeTransition.startTime const t = Math.min(1, elapsed / breakFreeTransition.durationMs) const eased = 1 - (1 - t) ** 3 // easeOutCubic const lerped: Pt[] = breakFreeTransition.fromPositions.map((from, i) => { const to = breakFreeTransition!.toPositions[i] return { x: from.x + (to.x - from.x) * eased, y: from.y + (to.y - from.y) * eased, } }) if (breakFreeTransition.kind === 'recipe') { applyInverseSolution(lerped) } else { applyPlaygroundSolution(lerped, breakFreeTransition.pointIds!) } needsDrawRef.current = true if (t < 1) { breakFreeTransitionId = requestAnimationFrame(stepBreakFreeTransition) } else { breakFreeTransition = null } } /** * Trigger break-free: set sticky flag, fire visual flash, clear tension, * and start an eased transition from the constrained pose to the solver * pose. The transition runs as its own RAF loop and the drag dispatcher * is gated until it completes — otherwise the user would see a hard snap * (the construction can rearrange dramatically when freed). */ function triggerBreakFree( world: { x: number; y: number }, derivedScreen: { x: number; y: number }, v: EuclidViewportState, w: number, h: number ): void { logEvent('break-free-triggered', { frame: constrainedDragFrameCount }) breakFree = true // Cancel any in-flight snap-to-cursor animation. Its remaining frames // would otherwise apply constrained-drag steps using a stale sub-Jacobian // on top of the solver's output — visible as flicker / undone work. if (snapAnimId != null) { cancelAnimationFrame(snapAnimId) snapAnimId = null } snapTargetWorld = null // Fire the break-free flash if (breakFreeFlashRef && dragInfluence) { const gId = dragInfluence.bestPointId if (gId) { const gPt = getPoint(constructionRef.current, gId) if (gPt) { const gScreen = worldToScreen2D( gPt.x, gPt.y, v.center.x, v.center.y, v.pixelsPerUnit, v.pixelsPerUnit, w, h ) breakFreeFlashRef.current = { startTime: performance.now(), givenScreen: { x: gScreen.x, y: gScreen.y }, derivedScreen: { x: derivedScreen.x, y: derivedScreen.y }, } } } } // Clear tension visuals + fade out the influence highlight — once the // constraint snaps the rubber-band cue no longer applies. if (influenceHighlightStateRef) { influenceHighlightStateRef.current.tension = 0 influenceHighlightStateRef.current.cursorScreen = null } if (hoveredDerivedPointIdRef) hoveredDerivedPointIdRef.current = null if (influentialGivenPointIdRef) influentialGivenPointIdRef.current = null // ── Compute the solver-pose target ONCE, then ease toward it. ── // Re-aiming the solver each frame during transition would let cursor // jitter wobble the in-flight target; locking it produces a clean // settle. Subsequent pointer moves resume normal solver tracking. if (!dragPointId || !solverState) { needsDrawRef.current = true return } const prop = propositionRef.current const recipe = RECIPE_REGISTRY[prop.id] const isPlayground = !!playgroundModeRef?.current if (isPlayground || !recipe) { const inputs = collectPlaygroundInputPositions() if (!inputs) { handleDerivedPointDragSolver(world) needsDrawRef.current = true return } const fromPositions = inputs.positions.map((p) => ({ x: p.x, y: p.y })) const forward = buildPlaygroundForward(dragPointId, inputs.pointIds) const solveResult = solveInverse(forward, inputs.positions, world, solverState) breakFreeTransition = { kind: 'playground', fromPositions, toPositions: solveResult.inputPositions, pointIds: inputs.pointIds, startTime: performance.now(), durationMs: 280, } } else { const currentInputs = collectRecipeInputPositions() if (!currentInputs) { handleDerivedPointDragSolver(world) needsDrawRef.current = true return } const fromPositions = currentInputs.map((p) => ({ x: p.x, y: p.y })) const targetRef = pointIdToRef(dragPointId) const isRecipePoint = recipe.inputSlots.some((s) => s.ref === targetRef) || recipe.ops.some((op) => { if (op.kind === 'intersection') return op.output === targetRef if (op.kind === 'produce') return op.output === targetRef if (op.kind === 'apply') return Object.values(op.outputs).includes(targetRef) return false }) const solveResult = isRecipePoint ? solveInverseKinematics( recipe, currentInputs, targetRef, world, RECIPE_REGISTRY, solverState ) : solveInverse(buildReplayForward(dragPointId), currentInputs, world, solverState) breakFreeTransition = { kind: 'recipe', fromPositions, toPositions: solveResult.inputPositions, startTime: performance.now(), durationMs: 280, } } breakFreeTransitionId = requestAnimationFrame(stepBreakFreeTransition) needsDrawRef.current = true } function handleDerivedPointDragConstrained(world: { x: number; y: number }): void { if (!dragPointId || !dragInfluence) return // First frame: just record position, no movement yet if (!prevDragWorld) { prevDragWorld = world return } prevDragWorld = world // kept for snap-cancel seeding; not used for delta // Periodically refresh the sub-Jacobian to stay accurate constrainedDragFrameCount++ if (constrainedDragFrameCount % 8 === 0) { const infCtx = buildInfluenceContext(dragPointId) if (infCtx) { const fresh = computeInfluence(infCtx.forward, infCtx.inputPositions, infCtx.pointIds) if (fresh && fresh.bestInputIndex === dragInfluence.bestInputIndex) { dragInfluence.subJacobian = fresh.subJacobian } } } // Update subJacobian on the highlight state during drag too if (influenceHighlightStateRef) { influenceHighlightStateRef.current.subJacobian = dragInfluence.subJacobian } // ── Compute tension: screen distance between cursor and derived point ── const { w, h } = getCSSSize() const v = viewportRef.current const derivedPt = getPoint(constructionRef.current, dragPointId) if (!derivedPt) return const derivedScreen = worldToScreen2D( derivedPt.x, derivedPt.y, v.center.x, v.center.y, v.pixelsPerUnit, v.pixelsPerUnit, w, h ) const cursorScreen = worldToScreen2D( world.x, world.y, v.center.x, v.center.y, v.pixelsPerUnit, v.pixelsPerUnit, w, h ) const screenDx = cursorScreen.x - derivedScreen.x const screenDy = cursorScreen.y - derivedScreen.y const screenDist = Math.sqrt(screenDx * screenDx + screenDy * screenDy) // Compute tension factor (0..1) const tension = screenDist <= TENSION_START_RADIUS ? 0 : screenDist >= BREAK_FREE_RADIUS ? 1 : (screenDist - TENSION_START_RADIUS) / (BREAK_FREE_RADIUS - TENSION_START_RADIUS) // Update tension on highlight state for visual rendering if (influenceHighlightStateRef) { influenceHighlightStateRef.current.tension = tension influenceHighlightStateRef.current.cursorScreen = { x: cursorScreen.x, y: cursorScreen.y } } // ── Check for break-free (cursor distance threshold) ── if (screenDist >= BREAK_FREE_RADIUS) { triggerBreakFree(world, derivedScreen, v, w, h) return } // ── Positional targeting (Newton step) instead of velocity integration ── // The derived point chases the cursor each frame: we measure the actual // residual error between where the derived IS and where it should be, // then apply a single inverse-Jacobian step to close the gap. Errors // get *corrected* per frame instead of *accumulated*, so closed cursor // paths produce closed derived paths — no spiral drift on circular or // repetitive motion. // // Tension dampens by limiting how far toward the cursor we aim each // frame, not by scaling the velocity. Same elastic feel, no drift. const dampen = 1 - tension * TENSION_DAMPEN const dx = dampen * (world.x - derivedPt.x) const dy = dampen * (world.y - derivedPt.y) if (Math.abs(dx) < 1e-10 && Math.abs(dy) < 1e-10) return // Get the current position of the influential given point const givenPointId = dragInfluence.bestPointId if (!givenPointId) return const givenPt = getPoint(constructionRef.current, givenPointId) if (!givenPt) return // Use sub-Jacobian to compute how to move the given point const newGivenPos = constrainedDragStep( { x: givenPt.x, y: givenPt.y }, { x: dx, y: dy }, dragInfluence.subJacobian ) if (!newGivenPos) { logEvent('degenerate-jacobian-breakfree') triggerBreakFree(world, derivedScreen, v, w, h) return } // ── Safety check: if the given point would fly off screen, break free ── // This catches degenerate Jacobians (e.g. line-line intersections at shallow angles) const givenMoveX = (newGivenPos.x - givenPt.x) * v.pixelsPerUnit const givenMoveY = (newGivenPos.y - givenPt.y) * v.pixelsPerUnit const givenMoveDist = Math.sqrt(givenMoveX * givenMoveX + givenMoveY * givenMoveY) const MAX_GIVEN_MOVE_PX = 200 // screen px per frame — anything larger is degenerate if (givenMoveDist > MAX_GIVEN_MOVE_PX) { logEvent('excessive-given-move-breakfree', { givenMovePx: givenMoveDist.toFixed(1) }) triggerBreakFree(world, derivedScreen, v, w, h) return } // Apply as a direct drag of the given point const prop = propositionRef.current // Snapshot the pre-mutation actions so we can revert the free-point // mutation below if the proposed move would destroy the dragged point. const prevActions = postCompletionActionsRef.current if (givenPt.origin === 'free') { // Update the free-point action postCompletionActionsRef.current = postCompletionActionsRef.current.map((a) => a.type === 'free-point' && a.id === givenPointId ? { ...a, x: newGivenPos.x, y: newGivenPos.y } : a ) } const positions = collectCurrentPositions() if (givenPt.origin === 'given') { positions.set(givenPointId, newGivenPos) } const computeFn = prop.computeGivenElements let givenElements: ConstructionElement[] if (computeFn) { givenElements = computeFn(positions) } else { givenElements = prop.givenElements.map((el) => { if (el.kind === 'point' && positions.has(el.id)) { const pos = positions.get(el.id)! return { ...el, x: pos.x, y: pos.y } } return el }) } const actions = postCompletionActionsRef.current const result = replayConstruction( givenElements, prop.steps, prop, actions, stepDataRef?.current ) // Guard: if the proposed frame would destroy the dragged point, escape // to the full solver. The canonical case is dragging an intersection // up to a tangency boundary — the sub-Jacobian becomes singular and // the constrained step (which only tweaks one given) can no longer // recover. Just rejecting the frame leaves the point stuck on the // boundary; handing off to break-free → LM solver lets it work in the // full input-position space and find a configuration where the point // lands at the cursor. const replayedDerived = getPoint(result.state, dragPointId) if (!replayedDerived) { logEvent('guard-fired-breakfree', { dragPointId, cursorWorld: { x: world.x.toFixed(3), y: world.y.toFixed(3) }, }) postCompletionActionsRef.current = prevActions triggerBreakFree(world, derivedScreen, v, w, h) return } const derivedMoveX = (replayedDerived.x - derivedPt.x) * v.pixelsPerUnit const derivedMoveY = (replayedDerived.y - derivedPt.y) * v.pixelsPerUnit const derivedMovePx = Math.sqrt(derivedMoveX * derivedMoveX + derivedMoveY * derivedMoveY) const replayedScreen = worldToScreen2D( replayedDerived.x, replayedDerived.y, v.center.x, v.center.y, v.pixelsPerUnit, v.pixelsPerUnit, w, h ) const newCursorErrPx = Math.sqrt( (cursorScreen.x - replayedScreen.x) ** 2 + (cursorScreen.y - replayedScreen.y) ** 2 ) logFrame({ mode: 'constrained', tension: tension.toFixed(2), cursorErrPx: screenDist.toFixed(0), newCursorErrPx: newCursorErrPx.toFixed(0), derivedMovePx: derivedMovePx.toFixed(1), givenMovePx: givenMoveDist.toFixed(1), subJ: dragInfluence.subJacobian.map((n) => n.toFixed(3)).join(','), }) constructionRef.current = result.state factStoreRef.current = result.factStore mergeProofFacts(factStoreRef.current, proofFactsRef.current) candidatesRef.current = result.candidates onReplayResult(result) needsDrawRef.current = true // Record the given point's new screen position for the motion trail if (motionTrailStateRef) { const updatedGivenPt = getPoint(result.state, givenPointId) if (updatedGivenPt) { const screen = worldToScreen2D( updatedGivenPt.x, updatedGivenPt.y, v.center.x, v.center.y, v.pixelsPerUnit, v.pixelsPerUnit, w, h ) recordTrailPosition(motionTrailStateRef.current, givenPointId, screen.x, screen.y) } } } /** * Handle drag of a derived (non-given, non-free, non-extend) point. * Routes to constrained or solver mode based on solverModeRef. * Once breakFree is set, stays in solver mode for the rest of the gesture. */ function handleDerivedPointDrag(world: { x: number; y: number }): void { // Break-free transition owns the construction state until it completes. // Pointer moves during this window are intentionally ignored — the // user sees the construction settle into its solver pose, and the // next move (after t = 1) drives normal cursor tracking. if (breakFreeTransition) return const useSolver = solverModeRef?.current ?? false if (useSolver || breakFree || !dragInfluence) { // Clear tension visuals + influence target — solver/break-free has no // single "controlling" given, so the rubber-band cue does not apply. if (influenceHighlightStateRef) { influenceHighlightStateRef.current.tension = 0 influenceHighlightStateRef.current.cursorScreen = null } if (hoveredDerivedPointIdRef) hoveredDerivedPointIdRef.current = null if (influentialGivenPointIdRef) influentialGivenPointIdRef.current = null handleDerivedPointDragSolver(world) } else { // Keep the influence highlight pointing at the drag pair so the // rubber band, ring vibration, and color shift are driven each frame. if (dragPointId && dragInfluence.bestPointId) { if (hoveredDerivedPointIdRef) hoveredDerivedPointIdRef.current = dragPointId if (influentialGivenPointIdRef) influentialGivenPointIdRef.current = dragInfluence.bestPointId } handleDerivedPointDragConstrained(world) } } /** * Handle direct drag of a given/free/extend point (existing behavior). */ function handleDirectPointDrag(world: { x: number; y: number }, prop: PropositionDef): void { const draggedPt = getAllPoints(constructionRef.current).find((pt) => pt.id === dragPointId) let actions = postCompletionActionsRef.current if (draggedPt?.origin === 'free') { // Update the free-point action coordinates in place actions = actions.map((a) => a.type === 'free-point' && a.id === dragPointId ? { ...a, x: world.x, y: world.y } : a ) postCompletionActionsRef.current = actions } else if (draggedPt?.origin === 'extend') { // Ray-constrained drag: project cursor onto the ray and update distance const extendAction = actions.find((a) => a.type === 'extend' && a.pointId === dragPointId) if (extendAction && extendAction.type === 'extend') { const basePt = getPoint(constructionRef.current, extendAction.baseId) const throughPt = getPoint(constructionRef.current, extendAction.throughId) if (basePt && throughPt) { const dx = throughPt.x - basePt.x const dy = throughPt.y - basePt.y const len = Math.sqrt(dx * dx + dy * dy) if (len > 0.001) { const dirX = dx / len const dirY = dy / len // Project cursor onto ray beyond throughPt const toX = world.x - throughPt.x const toY = world.y - throughPt.y const proj = toX * dirX + toY * dirY const clampedDist = Math.max(0.1, proj) // Update distance in the action actions = actions.map((a) => a.type === 'extend' && a.pointId === dragPointId ? { ...a, distance: clampedDist } : a ) postCompletionActionsRef.current = actions } } } } // Collect current given point positions (unchanged for free/extend point drag) const positions = collectCurrentPositions() if (draggedPt?.origin !== 'free' && draggedPt?.origin !== 'extend') { positions.set(dragPointId!, world) } // Compute fresh given elements const computeFn = prop.computeGivenElements let givenElements: ConstructionElement[] if (computeFn) { givenElements = computeFn(positions) } else { givenElements = prop.givenElements.map((el) => { if (el.kind === 'point' && positions.has(el.id)) { const pos = positions.get(el.id)! return { ...el, x: pos.x, y: pos.y } } return el }) } // Replay the full construction + any post-completion user actions const result = replayConstruction( givenElements, prop.steps, prop, actions, stepDataRef?.current ) constructionRef.current = result.state factStoreRef.current = result.factStore mergeProofFacts(factStoreRef.current, proofFactsRef.current) candidatesRef.current = result.candidates onReplayResult(result) needsDrawRef.current = true } function cleanupDragState() { dragPointId = null dragPointOrigin = null solverState = null dragInfluence = null prevDragWorld = null prevCursorWorldSolver = null solverStuckCount = 0 solverSaturatedCount = 0 constrainedDragFrameCount = 0 breakFree = false if (snapAnimId != null) { cancelAnimationFrame(snapAnimId) snapAnimId = null } snapTargetWorld = null if (breakFreeTransitionId != null) { cancelAnimationFrame(breakFreeTransitionId) breakFreeTransitionId = null } breakFreeTransition = null if (dragPointIdRef) dragPointIdRef.current = null pointerCapturedRef.current = false if (motionTrailStateRef) clearTrail(motionTrailStateRef.current) // Clear tension visuals + influence target on drag end so the highlight // fades out (it will reappear if the user re-hovers a derived point). if (influenceHighlightStateRef) { influenceHighlightStateRef.current.tension = 0 influenceHighlightStateRef.current.cursorScreen = null } if (hoveredDerivedPointIdRef) hoveredDerivedPointIdRef.current = null if (influentialGivenPointIdRef) influentialGivenPointIdRef.current = null } function handlePointerUp(e: PointerEvent) { if (!dragPointId) return e.stopPropagation() cleanupDragState() canvas!.style.cursor = hoveredDraggableId ? 'grab' : '' // Construction state may have changed during drag — invalidate the // per-derived-point influence cache so the field re-derives next move. clearFieldCache() needsDrawRef.current = true onDragEnd?.() } function handlePointerCancel() { if (!dragPointId) return cleanupDragState() hoveredDraggableId = null canvas!.style.cursor = '' clearFieldCache() needsDrawRef.current = true } // ── Shift key: temporary solver mode override ── function handleKeyDown(e: KeyboardEvent) { if (e.key === 'Shift' && solverModeRef) { solverModeRef.current = true } } function handleKeyUp(e: KeyboardEvent) { if (e.key === 'Shift' && solverModeRef) { solverModeRef.current = false } } // Register with capture: true to intercept before tool interaction and pan/zoom canvas.addEventListener('pointerdown', handlePointerDown, { capture: true }) canvas.addEventListener('pointermove', handlePointerMove, { capture: true }) canvas.addEventListener('pointerup', handlePointerUp, { capture: true }) canvas.addEventListener('pointercancel', handlePointerCancel, { capture: true }) document.addEventListener('keydown', handleKeyDown) document.addEventListener('keyup', handleKeyUp) return () => { canvas.removeEventListener('pointerdown', handlePointerDown, { capture: true }) canvas.removeEventListener('pointermove', handlePointerMove, { capture: true }) canvas.removeEventListener('pointerup', handlePointerUp, { capture: true }) canvas.removeEventListener('pointercancel', handlePointerCancel, { capture: true }) document.removeEventListener('keydown', handleKeyDown) document.removeEventListener('keyup', handleKeyUp) } }, [ canvasRef, propositionRef, constructionRef, factStoreRef, viewportRef, isCompleteRef, activeToolRef, needsDrawRef, pointerCapturedRef, candidatesRef, postCompletionActionsRef, onReplayResult, onDragStart, dragPointIdRef, getCanvasRect, onDragEnd, ]) } /** * Whether a point origin represents a derived (solver-eligible) point. * Given, free, and extend points are handled by direct drag. */ function isDerivedOrigin(origin: ConstructionPoint['origin']): boolean { return origin !== 'given' && origin !== 'free' && origin !== 'extend' } |