[feature] snapping (#168)

* defer cloning

* basic snapping

* Improves algorithm for snap points, rendering

* Improves snapping, snaplines

* Enables a clone to snap to its parent

* Adds overlay

* Fix overlay, zoom scaling for distance and speed

packages/core/package.json

@@ -41,7 +41,7 @@
     "@types/react-dom": "^16.9.9",
     "@typescript-eslint/eslint-plugin": "^4.30.0",
     "@typescript-eslint/parser": "^4.30.0",
-    "esbuild": "^0.12.24",
+    "esbuild": "^0.13.8",
     "eslint": "^7.32.0",
     "lerna": "^4.0.0",
     "react": ">=16.8",

packages/core/scripts/dev.js

@@ -6,10 +6,10 @@ const name = process.env.npm_package_name || ''
 async function main() {
   esbuild.build({
     entryPoints: ['./src/index.ts'],
-    outdir: 'dist/cjs',
+    outdir: 'dist/esm',
     minify: false,
     bundle: true,
-    format: 'cjs',
+    format: 'esm',
     target: 'es6',
     jsxFactory: 'React.createElement',
     jsxFragment: 'React.Fragment',

packages/core/scripts/pre-dev.js

@@ -13,10 +13,10 @@ async function main() {
 
   esbuild.build({
     entryPoints: ['./src/index.ts'],
-    outdir: 'dist/cjs',
+    outdir: 'dist/esm',
     minify: false,
     bundle: true,
-    format: 'cjs',
+    format: 'esm',
     target: 'es6',
     jsxFactory: 'React.createElement',
     jsxFragment: 'React.Fragment',

packages/core/src/components/bounds/bounds.tsx

@@ -38,8 +38,10 @@ export const Bounds = React.memo(
     const smallDimension = Math.min(bounds.width, bounds.height) * zoom
     // If the bounds are small, don't show the rotate handle
     const showRotateHandle = !isHidden && !isLocked && smallDimension > 32
-    // If the bounds are very small, don't show the corner handles
+    // If the bounds are very small, don't show the edge handles
-    const showHandles = !isHidden && !isLocked && smallDimension > 16
+    const showEdgeHandles = !isHidden && !isLocked && smallDimension > 24
+    // If the bounds are very very small, don't show the corner handles
+    const showCornerHandles = !isHidden && !isLocked && smallDimension > 20
 
     return (
       <Container bounds={bounds} rotation={rotation}>
@@ -50,62 +52,62 @@ export const Bounds = React.memo(
             size={size}
             bounds={bounds}
             edge={TLBoundsEdge.Top}
-            isHidden={!showHandles}
+            isHidden={!showEdgeHandles}
           />
           <EdgeHandle
             targetSize={targetSize}
             size={size}
             bounds={bounds}
             edge={TLBoundsEdge.Right}
-            isHidden={!showHandles}
+            isHidden={!showEdgeHandles}
           />
           <EdgeHandle
             targetSize={targetSize}
             size={size}
             bounds={bounds}
             edge={TLBoundsEdge.Bottom}
-            isHidden={!showHandles}
+            isHidden={!showEdgeHandles}
           />
           <EdgeHandle
             targetSize={targetSize}
             size={size}
             bounds={bounds}
             edge={TLBoundsEdge.Left}
-            isHidden={!showHandles}
+            isHidden={!showEdgeHandles}
           />
           <CornerHandle
             targetSize={targetSize}
             size={size}
             bounds={bounds}
-            isHidden={isHidden}
+            isHidden={isHidden || !showCornerHandles}
             corner={TLBoundsCorner.TopLeft}
           />
           <CornerHandle
             targetSize={targetSize}
             size={size}
             bounds={bounds}
-            isHidden={isHidden}
+            isHidden={isHidden || !showCornerHandles}
             corner={TLBoundsCorner.TopRight}
           />
           <CornerHandle
             targetSize={targetSize}
             size={size}
             bounds={bounds}
-            isHidden={isHidden}
+            isHidden={isHidden || !showCornerHandles}
             corner={TLBoundsCorner.BottomRight}
           />
           <CornerHandle
             targetSize={targetSize}
             size={size}
             bounds={bounds}
-            isHidden={isHidden}
+            isHidden={isHidden || !showCornerHandles}
             corner={TLBoundsCorner.BottomLeft}
           />
           <RotateHandle
             targetSize={targetSize}
             size={size}
             bounds={bounds}
-            isHidden={!showHandles || !showRotateHandle}
+            isHidden={!showEdgeHandles || !showRotateHandle}
           />
           {showCloneButtons && <CloneButtons bounds={bounds} />}
         </SVGContainer>

packages/core/src/components/canvas/canvas.tsx

@@ -8,7 +8,7 @@ import {
   useCameraCss,
   useKeyEvents,
 } from '+hooks'
-import type { TLBinding, TLPage, TLPageState, TLShape, TLUsers } from '+types'
+import type { TLBinding, TLPage, TLPageState, TLShape, TLSnapLine, TLUsers } from '+types'
 import { ErrorFallback } from '+components/error-fallback'
 import { ErrorBoundary } from '+components/error-boundary'
 import { Brush } from '+components/brush'
@@ -17,6 +17,8 @@ import { Users } from '+components/users'
 import { useResizeObserver } from '+hooks/useResizeObserver'
 import { inputs } from '+inputs'
 import { UsersIndicators } from '+components/users-indicators'
+import { SnapLines } from '+components/snap-lines/snap-lines'
+import { Overlay } from '+components/overlay'
 
 function resetError() {
   void null
@@ -25,6 +27,7 @@ function resetError() {
 interface CanvasProps<T extends TLShape, M extends Record<string, unknown>> {
   page: TLPage<T, TLBinding>
   pageState: TLPageState
+  snapLines?: TLSnapLine[]
   users?: TLUsers<T>
   userId?: string
   hideBounds?: boolean
@@ -39,6 +42,7 @@ export function Canvas<T extends TLShape, M extends Record<string, unknown>>({
   id,
   page,
   pageState,
+  snapLines,
   users,
   userId,
   meta,
@@ -87,6 +91,9 @@ export function Canvas<T extends TLShape, M extends Record<string, unknown>>({
             {users && <Users userId={userId} users={users} />}
           </div>
         </ErrorBoundary>
+        <Overlay camera={pageState.camera}>
+          {snapLines && <SnapLines snapLines={snapLines} />}
+        </Overlay>
       </div>
     </div>
   )

packages/core/src/components/overlay/index.ts

@@ -0,0 +1 @@
+export * from './overlay'

packages/core/src/components/overlay/overlay.tsx

@@ -0,0 +1,24 @@
+import * as React from 'react'
+
+export function Overlay({
+  camera,
+  children,
+}: {
+  camera: { point: number[]; zoom: number }
+  children: React.ReactNode
+}) {
+  const l = 2.5 / camera.zoom
+  return (
+    <svg className="tl-overlay">
+      <defs>
+        <g id="tl-snap-point">
+          <path
+            className="tl-snap-point"
+            d={`M ${-l},${-l} L ${l},${l} M ${-l},${l} L ${l},${-l}`}
+          />
+        </g>
+      </defs>
+      <g transform={`scale(${camera.zoom}) translate(${camera.point})`}>{children}</g>
+    </svg>
+  )
+}

packages/core/src/components/renderer/renderer.tsx

@@ -12,7 +12,7 @@ import type {
 import { Canvas } from '../canvas'
 import { Inputs } from '../../inputs'
 import { useTLTheme, TLContext, TLContextType } from '../../hooks'
-import type { TLShapeUtil, TLUsers } from '+index'
+import type { TLShapeUtil, TLSnapLine, TLUsers } from '+index'
 
 export interface RendererProps<T extends TLShape, E extends Element = any, M = any>
   extends Partial<TLCallbacks<T>> {
@@ -40,6 +40,10 @@ export interface RendererProps<T extends TLShape, E extends Element = any, M = a
    * (optional) The current users to render.
    */
   users?: TLUsers<T>
+  /**
+   * (optional) The current snap lines to render.
+   */
+  snapLines?: TLSnapLine[]
   /**
    * (optional) The current user's id, used to identify the user.
    */
@@ -97,6 +101,7 @@ export function Renderer<T extends TLShape, E extends Element, M extends Record<
   userId,
   theme,
   meta,
+  snapLines,
   containerRef,
   hideHandles = false,
   hideIndicators = false,
@@ -132,6 +137,7 @@ export function Renderer<T extends TLShape, E extends Element, M extends Record<
         id={id}
         page={page}
         pageState={pageState}
+        snapLines={snapLines}
         users={users}
         userId={userId}
         hideBounds={hideBounds}

packages/core/src/components/snap-lines/index.ts

@@ -0,0 +1 @@
+export * from './snap-lines'

packages/core/src/components/snap-lines/snap-lines.tsx

@@ -0,0 +1,32 @@
+import * as React from 'react'
+import type { TLSnapLine } from '+types'
+import Utils from '+utils'
+
+export function SnapLines({ snapLines }: { snapLines: TLSnapLine[] }) {
+  return (
+    <>
+      {snapLines.map((snapLine, i) => (
+        <SnapLine key={i} snapLine={snapLine} />
+      ))}
+    </>
+  )
+}
+
+export function SnapLine({ snapLine }: { snapLine: TLSnapLine }) {
+  const bounds = Utils.getBoundsFromPoints(snapLine)
+
+  return (
+    <>
+      <line
+        className="tl-snap-line"
+        x1={bounds.minX}
+        y1={bounds.minY}
+        x2={bounds.maxX}
+        y2={bounds.maxY}
+      />
+      {snapLine.map(([x, y], i) => (
+        <use key={i} href="#tl-snap-point" x={x} y={y} />
+      ))}
+    </>
+  )
+}

packages/core/src/hooks/useShapeEvents.tsx

@@ -69,6 +69,8 @@ export function useShapeEvents(id: string, disable = false) {
       if (!inputs.pointerIsValid(e)) return
       if (disable) return
 
+      e.stopPropagation()
+
       if (inputs.pointer && e.pointerId !== inputs.pointer.pointerId) return
 
       const info = inputs.pointerMove(e, id)

packages/core/src/hooks/useStyle.tsx

@@ -66,6 +66,7 @@ const css = (strings: TemplateStringsArray, ...args: unknown[]) =>
   )
 
 const defaultTheme: TLTheme = {
+  accent: 'rgb(255, 0, 0)',
   brushFill: 'rgba(0,0,0,.05)',
   brushStroke: 'rgba(0,0,0,.25)',
   selectStroke: 'rgb(66, 133, 244)',
@@ -133,6 +134,24 @@ const tlcss = css`
     box-sizing: border-box;
   }
 
+  .tl-overlay {
+    position: absolute;
+    width: 100%;
+    height: 100%;
+    touch-action: none;
+    pointer-events: none;
+  }
+
+  .tl-snap-line {
+    stroke: var(--tl-accent);
+    stroke-width: calc(1px * var(--tl-scale));
+  }
+
+  .tl-snap-point {
+    stroke: var(--tl-accent);
+    stroke-width: calc(1px * var(--tl-scale));
+  }
+
   .tl-canvas {
     position: absolute;
     width: 100%;

packages/core/src/types.ts

@@ -42,6 +42,8 @@ export interface TLUser<T extends TLShape> {
 
 export type TLUsers<T extends TLShape, U extends TLUser<T> = TLUser<T>> = Record<string, U>
 
+export type TLSnapLine = number[][]
+
 export interface TLHandle {
   id: string
   index: number
@@ -112,6 +114,7 @@ export interface TLBinding<M = any> {
 }
 
 export interface TLTheme {
+  accent?: string
   brushFill?: string
   brushStroke?: string
   selectFill?: string
@@ -242,6 +245,11 @@ export interface TLBounds {
   rotation?: number
 }
 
+export interface TLBoundsWithCenter extends TLBounds {
+  midX: number
+  midY: number
+}
+
 export type TLIntersection = {
   didIntersect: boolean
   message: string

packages/core/src/utils/utils.ts

@@ -6,7 +6,7 @@ import type React from 'react'
 import { TLBezierCurveSegment, TLBounds, TLBoundsCorner, TLBoundsEdge } from '../types'
 import { Vec } from '@tldraw/vec'
 import './polyfills'
-import type { Patch } from '+index'
+import type { Patch, TLBoundsWithCenter } from '+index'
 
 export class Utils {
   /* -------------------------------------------------- */
@@ -1519,6 +1519,146 @@ left past the initial left edge) then swap points on that axis.
     return [bounds.minX + bounds.width / 2, bounds.minY + bounds.height / 2]
   }
 
+  /**
+   * Get a bounding box with a midX and midY.
+   * @param bounds
+   */
+  static getBoundsWithCenter(bounds: TLBounds): TLBounds & { midX: number; midY: number } {
+    return {
+      ...bounds,
+      midX: bounds.minX + bounds.width / 2,
+      midY: bounds.minY + bounds.height / 2,
+    }
+  }
+
+  static getSnapPoints = (
+    bounds: TLBoundsWithCenter,
+    others: TLBoundsWithCenter[],
+    distance: number,
+    isCareful: boolean
+  ) => {
+    const A = { ...bounds }
+
+    const offset = [0, 0]
+    const snapLines: number[][][] = []
+
+    // 1.
+    // Find the snap points for the x and y axes
+
+    let xs = null as { B: TLBoundsWithCenter; i: number } | null
+    let ys = null as { B: TLBoundsWithCenter; i: number } | null
+
+    const fxs = [A.midX, A.minX, A.maxX]
+    const fys = [A.midY, A.minY, A.maxY]
+
+    for (const B of others) {
+      if (!xs) {
+        const txs = [B.midX, B.minX, B.maxX]
+
+        fxs.forEach((f, i) =>
+          txs.forEach((t, k) => {
+            // If we're not dragging carefully, only snap to
+            // matching points, (e.g. min to min, mid to mid)
+            if (xs || !(isCareful || i === k)) return
+
+            if (Math.abs(t - f) < distance) {
+              xs = { B, i }
+
+              offset[0] = [
+                // How far to offset the delta on the x axis in
+                // order to "snap" the selection to the right place
+                A.midX - t,
+                A.midX - (t + A.width / 2),
+                A.midX - (t - A.width / 2),
+              ][i]
+
+              // Also apply the offset to the bounds
+              A.minX -= offset[0]
+              A.midX -= offset[0]
+              A.maxX -= offset[0]
+            }
+          })
+        )
+      }
+
+      if (!ys) {
+        const tys = [B.midY, B.minY, B.maxY]
+
+        fys.forEach((f, i) =>
+          tys.forEach((t, k) => {
+            if (ys || !(isCareful || i === k)) return
+
+            if (Math.abs(t - f) < distance) {
+              ys = { B, i }
+
+              offset[1] = [
+                //
+                A.midY - t,
+                A.midY - (t + A.height / 2),
+                A.midY - (t - A.height / 2),
+              ][i]
+
+              A.minY -= offset[1]
+              A.midY -= offset[1]
+              A.maxY -= offset[1]
+            }
+          })
+        )
+      }
+
+      if (xs && ys) break
+    }
+
+    // 2.
+    // Calculate snap lines based on adjusted bounds A. This has
+    // to happen after we've adjusted both dimensions x and y of
+    // the bounds A!
+
+    if (xs) {
+      const { i, B } = xs
+      const x = [A.midX, A.minX, A.maxX][i % 3]
+
+      // If A is snapped at its center, show include only the midY;
+      // otherwise, include both its minY and maxY.
+      snapLines.push(
+        i === 0
+          ? [
+              [x, A.midY],
+              [x, B.minY],
+              [x, B.maxY],
+            ]
+          : [
+              [x, A.minY],
+              [x, A.maxY],
+              [x, B.minY],
+              [x, B.maxY],
+            ]
+      )
+    }
+
+    if (ys) {
+      const { i, B } = ys
+      const y = [A.midY, A.minY, A.maxY][i % 3]
+
+      snapLines.push(
+        i === 0
+          ? [
+              [A.midX, y],
+              [B.minX, y],
+              [B.maxX, y],
+            ]
+          : [
+              [A.minX, y],
+              [A.maxX, y],
+              [B.minX, y],
+              [B.maxX, y],
+            ]
+      )
+    }
+
+    return { offset, snapLines }
+  }
+
   /* -------------------------------------------------- */
   /*                Lists and Collections               */
   /* -------------------------------------------------- */
@@ -1684,6 +1824,59 @@ left past the initial left edge) then swap points on that axis.
   /*                   Browser and DOM                  */
   /* -------------------------------------------------- */
 
+  /**
+   * Get balanced dash-strokearray and dash-strokeoffset properties for a path of a given length.
+   * @param length The length of the path.
+   * @param strokeWidth The shape's stroke-width property.
+   * @param style The stroke's style: "dashed" or "dotted" (default "dashed").
+   * @param snap An interval for dashes (e.g. 4 will produce arrays with 4, 8, 16, etc dashes).
+   */
+  static getPerfectDashProps(
+    length: number,
+    strokeWidth: number,
+    style: 'dashed' | 'dotted' | string,
+    snap = 1,
+    outset = true
+  ): {
+    strokeDasharray: string
+    strokeDashoffset: string
+  } {
+    let dashLength: number
+    let strokeDashoffset: string
+    let ratio: number
+
+    if (style.toLowerCase() === 'dashed') {
+      dashLength = strokeWidth * 2
+      ratio = 1
+      strokeDashoffset = outset ? (dashLength / 2).toString() : '0'
+    } else if (style.toLowerCase() === 'dotted') {
+      dashLength = strokeWidth / 100
+      ratio = 100
+      strokeDashoffset = '0'
+    } else {
+      return {
+        strokeDasharray: 'none',
+        strokeDashoffset: 'none',
+      }
+    }
+
+    let dashes = Math.floor(length / dashLength / (2 * ratio))
+
+    dashes -= dashes % snap
+
+    dashes = Math.max(dashes, 4)
+
+    const gapLength = Math.max(
+      dashLength,
+      (length - dashes * dashLength) / (outset ? dashes : dashes - 1)
+    )
+
+    return {
+      strokeDasharray: [dashLength, gapLength].join(' '),
+      strokeDashoffset,
+    }
+  }
+
   static isMobileSize() {
     if (typeof window === 'undefined') return false
     return window.innerWidth < 768

packages/dev/package.json

@@ -35,7 +35,7 @@
     "@types/react-router-dom": "^5.1.8",
     "concurrently": "6.0.1",
     "create-serve": "1.0.1",
-    "esbuild": "^0.12.26",
+    "esbuild": "^0.13.8",
     "rimraf": "3.0.2",
     "typescript": "4.2.3"
   },

packages/intersect/package.json

@@ -39,7 +39,7 @@
     "@types/node": "^16.7.10",
     "@typescript-eslint/eslint-plugin": "^4.30.0",
     "@typescript-eslint/parser": "^4.30.0",
-    "esbuild": "^0.12.24",
+    "esbuild": "^0.13.8",
     "eslint": "^7.32.0",
     "lerna": "^4.0.0",
     "ts-node": "^10.2.1",

packages/tldraw/package.json

@@ -40,7 +40,7 @@
     "@types/react-dom": "^16.9.9",
     "@typescript-eslint/eslint-plugin": "^4.30.0",
     "@typescript-eslint/parser": "^4.30.0",
-    "esbuild": "^0.12.24",
+    "esbuild": "^0.13.8",
     "eslint": "^7.32.0",
     "lerna": "^4.0.0",
     "ts-node": "^10.2.1",

packages/tldraw/scripts/dev.js

@@ -6,10 +6,10 @@ const name = process.env.npm_package_name || ''
 async function main() {
   esbuild.build({
     entryPoints: ['./src/index.ts'],
-    outdir: 'dist/cjs',
+    outdir: 'dist/esm',
     minify: false,
     bundle: true,
-    format: 'cjs',
+    format: 'esm',
     target: 'es6',
     jsxFactory: 'React.createElement',
     jsxFragment: 'React.Fragment',

packages/tldraw/scripts/pre-dev.js

@@ -13,10 +13,10 @@ async function main() {
 
   esbuild.build({
     entryPoints: ['./src/index.ts'],
-    outdir: 'dist/cjs',
+    outdir: 'dist/esm',
     minify: false,
     bundle: true,
-    format: 'cjs',
+    format: 'esm',
     target: 'es6',
     jsxFactory: 'React.createElement',
     jsxFragment: 'React.Fragment',

packages/tldraw/src/components/tldraw/tldraw.tsx

@@ -29,6 +29,8 @@ const isHideBoundsShapeSelector = (s: Data) => {
 
 const pageSelector = (s: Data) => s.document.pages[s.appState.currentPageId]
 
+const snapLinesSelector = (s: Data) => s.appState.snapLines
+
 const usersSelector = (s: Data) => s.room?.users
 
 const pageStateSelector = (s: Data) => s.document.pageStates[s.appState.currentPageId]
@@ -149,6 +151,8 @@ function InnerTldraw({
 
   const pageState = useSelector(pageStateSelector)
 
+  const snapLines = useSelector(snapLinesSelector)
+
   const users = useSelector(usersSelector)
 
   const isDarkMode = useSelector(isDarkModeSelector)
@@ -217,6 +221,7 @@ function InnerTldraw({
           containerRef={rWrapper}
           page={page}
           pageState={pageState}
+          snapLines={snapLines}
           users={users}
           userId={tlstate.state.room?.userId}
           shapeUtils={tldrawShapeUtils}

packages/tldraw/src/shape/shape-styles.ts

@@ -150,56 +150,3 @@ export const defaultStyle: ShapeStyles = {
   isFilled: false,
   dash: DashStyle.Draw,
 }
-
-/**
- * Get balanced dash-strokearray and dash-strokeoffset properties for a path of a given length.
- * @param length The length of the path.
- * @param strokeWidth The shape's stroke-width property.
- * @param style The stroke's style: "dashed" or "dotted" (default "dashed").
- * @param snap An interval for dashes (e.g. 4 will produce arrays with 4, 8, 16, etc dashes).
- */
-export function getPerfectDashProps(
-  length: number,
-  strokeWidth: number,
-  style: DashStyle,
-  snap = 1,
-  outset = true
-): {
-  strokeDasharray: string
-  strokeDashoffset: string
-} {
-  let dashLength: number
-  let strokeDashoffset: string
-  let ratio: number
-
-  if (style === DashStyle.Solid || style === DashStyle.Draw) {
-    return {
-      strokeDasharray: 'none',
-      strokeDashoffset: 'none',
-    }
-  } else if (style === DashStyle.Dashed) {
-    dashLength = strokeWidth * 2
-    ratio = 1
-    strokeDashoffset = outset ? (dashLength / 2).toString() : '0'
-  } else {
-    dashLength = strokeWidth / 100
-    ratio = 100
-    strokeDashoffset = '0'
-  }
-
-  let dashes = Math.floor(length / dashLength / (2 * ratio))
-
-  dashes -= dashes % snap
-
-  dashes = Math.max(dashes, 4)
-
-  const gapLength = Math.max(
-    dashLength,
-    (length - dashes * dashLength) / (outset ? dashes : dashes - 1)
-  )
-
-  return {
-    strokeDasharray: [dashLength, gapLength].join(' '),
-    strokeDashoffset,
-  }
-}

packages/tldraw/src/shape/shapes/arrow/arrow.tsx

@@ -2,7 +2,7 @@ import * as React from 'react'
 import { ShapeUtil, SVGContainer, TLBounds, Utils, TLHandle } from '@tldraw/core'
 import { Vec } from '@tldraw/vec'
 import getStroke from 'perfect-freehand'
-import { defaultStyle, getPerfectDashProps, getShapeStyle } from '~shape/shape-styles'
+import { defaultStyle, getShapeStyle } from '~shape/shape-styles'
 import {
   ArrowShape,
   Decoration,
@@ -102,7 +102,7 @@ export const Arrow = new ShapeUtil<ArrowShape, SVGSVGElement, TLDrawMeta>(() =>
         ? renderFreehandArrowShaft(shape)
         : 'M' + Vec.round(start.point) + 'L' + Vec.round(end.point)
 
-      const { strokeDasharray, strokeDashoffset } = getPerfectDashProps(
+      const { strokeDasharray, strokeDashoffset } = Utils.getPerfectDashProps(
         arrowDist,
         strokeWidth * 1.618,
         shape.style.dash,
@@ -154,7 +154,7 @@ export const Arrow = new ShapeUtil<ArrowShape, SVGSVGElement, TLDrawMeta>(() =>
         ? renderCurvedFreehandArrowShaft(shape, circle, length, easing)
         : getArrowArcPath(start, end, circle, shape.bend)
 
-      const { strokeDasharray, strokeDashoffset } = getPerfectDashProps(
+      const { strokeDasharray, strokeDashoffset } = Utils.getPerfectDashProps(
         Math.abs(length),
         sw,
         shape.style.dash,

packages/tldraw/src/shape/shapes/ellipse/ellipse.tsx

@@ -2,7 +2,7 @@ import * as React from 'react'
 import { SVGContainer, Utils, ShapeUtil, TLTransformInfo, TLBounds } from '@tldraw/core'
 import { Vec } from '@tldraw/vec'
 import { DashStyle, EllipseShape, TLDrawShapeType, TLDrawMeta } from '~types'
-import { defaultStyle, getPerfectDashProps, getShapeStyle } from '~shape/shape-styles'
+import { defaultStyle, getShapeStyle } from '~shape/shape-styles'
 import { getStrokeOutlinePoints, getStrokePoints } from 'perfect-freehand'
 import {
   intersectBoundsEllipse,
@@ -82,7 +82,7 @@ export const Ellipse = new ShapeUtil<EllipseShape, SVGSVGElement, TLDrawMeta>(()
 
     const perimeter = Math.PI * (rx + ry) * (1 + (3 * h) / (10 + Math.sqrt(4 - 3 * h)))
 
-    const { strokeDasharray, strokeDashoffset } = getPerfectDashProps(
+    const { strokeDasharray, strokeDashoffset } = Utils.getPerfectDashProps(
       perimeter < 64 ? perimeter * 2 : perimeter,
       strokeWidth * 1.618,
       shape.style.dash,

packages/tldraw/src/shape/shapes/rectangle/rectangle.tsx

@@ -1,13 +1,10 @@
 import * as React from 'react'
 import { Utils, SVGContainer, ShapeUtil } from '@tldraw/core'
 import { Vec } from '@tldraw/vec'
-import getStroke, { getStrokeOutlinePoints, getStrokePoints } from 'perfect-freehand'
+import getStroke, { getStrokePoints } from 'perfect-freehand'
-import { getPerfectDashProps, defaultStyle, getShapeStyle } from '~shape/shape-styles'
+import { defaultStyle, getShapeStyle } from '~shape/shape-styles'
 import { RectangleShape, DashStyle, TLDrawShapeType, TLDrawMeta } from '~types'
 import { getBoundsRectangle, transformRectangle, transformSingleRectangle } from '../shared'
-import { EASINGS } from '~state/utils'
-
-const pathCache = new WeakMap<number[], string>([])
 
 export const Rectangle = new ShapeUtil<RectangleShape, SVGSVGElement, TLDrawMeta>(() => ({
   type: TLDrawShapeType.Rectangle,
@@ -36,7 +33,7 @@ export const Rectangle = new ShapeUtil<RectangleShape, SVGSVGElement, TLDrawMeta
     const strokeWidth = +styles.strokeWidth
 
     if (style.dash === DashStyle.Draw) {
-      const pathData = Utils.getFromCache(pathCache, shape.size, () => getRectanglePath(shape))
+      const pathData = getRectanglePath(shape)
 
       return (
         <SVGContainer ref={ref} id={shape.id + '_svg'} {...events}>
@@ -80,7 +77,7 @@ export const Rectangle = new ShapeUtil<RectangleShape, SVGSVGElement, TLDrawMeta
     ]
 
     const paths = strokes.map(([start, end, length], i) => {
-      const { strokeDasharray, strokeDashoffset } = getPerfectDashProps(
+      const { strokeDasharray, strokeDashoffset } = Utils.getPerfectDashProps(
         length,
         strokeWidth * 1.618,
         shape.style.dash

packages/tldraw/src/state/constants.ts

@@ -0,0 +1,2 @@
+export const FIT_TO_SCREEN_PADDING = 128
+export const SNAP_DISTANCE = 5

packages/tldraw/src/state/session/sessions/arrow/arrow.session.ts

@@ -74,7 +74,7 @@ export class ArrowSession implements Session {
 
   start = () => void null
 
-  update = (data: Data, point: number[], shiftKey: boolean, altKey: boolean, metaKey: boolean) => {
+  update = (data: Data, point: number[], shiftKey = false, altKey = false, metaKey = false) => {
     const { initialShape } = this
 
     const page = TLDR.getPage(data, data.appState.currentPageId)

packages/tldraw/src/state/session/sessions/draw/draw.session.ts

@@ -31,7 +31,7 @@ export class DrawSession implements Session {
 
   start = () => void null
 
-  update = (data: Data, point: number[], shiftKey: boolean) => {
+  update = (data: Data, point: number[], shiftKey = false, altKey = false, metaKey = false) => {
     const { shapeId } = this
 
     // Even if we're not locked yet, we base the future locking direction

packages/tldraw/src/state/session/sessions/grid/grid.session.ts

@@ -60,7 +60,7 @@ export class GridSession implements Session {
     return clone
   }
 
-  update = (data: Data, point: number[], shiftKey: boolean, altKey: boolean, metaKey: boolean) => {
+  update = (data: Data, point: number[], shiftKey = false, altKey = false, metaKey = false) => {
     const nextShapes: Patch<Record<string, TLDrawShape>> = {}
 
     const nextPageState: Patch<TLPageState> = {}

packages/tldraw/src/state/session/sessions/handle/handle.session.ts

@@ -27,7 +27,7 @@ export class HandleSession implements Session {
 
   start = () => void null
 
-  update = (data: Data, point: number[], shiftKey: boolean, altKey: boolean, metaKey: boolean) => {
+  update = (data: Data, point: number[], shiftKey = false, altKey = false, metaKey = false) => {
     const { initialShape } = this
     const { currentPageId } = data.appState
 

packages/tldraw/src/state/session/sessions/rotate/rotate.session.ts

@@ -23,7 +23,7 @@ export class RotateSession implements Session {
 
   start = () => void null
 
-  update = (data: Data, point: number[], isLocked = false) => {
+  update = (data: Data, point: number[], shiftKey = false, altKey = false, metaKey = false) => {
     const { commonBoundsCenter, initialShapes } = this.snapshot
 
     const pageId = data.appState.currentPageId
@@ -32,7 +32,7 @@ export class RotateSession implements Session {
 
     let directionDelta = Vec.angle(commonBoundsCenter, point) - this.initialAngle
 
-    if (isLocked) {
+    if (shiftKey) {
       directionDelta = Utils.snapAngleToSegments(directionDelta, 24) // 15 degrees
     }
 
@@ -41,7 +41,7 @@ export class RotateSession implements Session {
       const { rotation = 0 } = shape
       let shapeDelta = 0
 
-      if (isLocked) {
+      if (shiftKey) {
         const snappedRotation = Utils.snapAngleToSegments(rotation, 24)
         shapeDelta = snappedRotation - rotation
       }
@@ -50,7 +50,7 @@ export class RotateSession implements Session {
         shape,
         center,
         commonBoundsCenter,
-        isLocked ? directionDelta + shapeDelta : directionDelta
+        shiftKey ? directionDelta + shapeDelta : directionDelta
       )
 
       if (change) {

packages/tldraw/src/state/session/sessions/transform-single/transform-single.session.ts

@@ -29,7 +29,7 @@ export class TransformSingleSession implements Session {
 
   start = () => void null
 
-  update = (data: Data, point: number[], shiftKey: boolean) => {
+  update = (data: Data, point: number[], shiftKey = false, altKey = false, metaKey = false) => {
     const { transformType } = this
 
     const { initialShapeBounds, initialShape, id } = this.snapshot

packages/tldraw/src/state/session/sessions/transform/transform.session.ts

@@ -32,7 +32,7 @@ export class TransformSession implements Session {
   start = () => void null
 
   // eslint-disable-next-line @typescript-eslint/no-unused-vars
-  update = (data: Data, point: number[], shiftKey: boolean, altKey: boolean, metaKey: boolean) => {
+  update = (data: Data, point: number[], shiftKey = false, altKey = false, metaKey = false) => {
     const {
       transformType,
       snapshot: { shapeBounds, initialBounds, isAllAspectRatioLocked },

packages/tldraw/src/state/session/sessions/translate/translate.session.spec.ts

@@ -326,3 +326,13 @@ describe('When creating with a translate session', () => {
     expect(tlstate.getShape('rect1')).toBe(undefined)
   })
 })
+
+describe('When snapping', () => {
+  it.todo('Does not snap when moving quicky')
+  it.todo('Snaps only matching edges when moving slowly')
+  it.todo('Snaps any edge to any edge when moving very slowly')
+  it.todo('Snaps a clone to its parent')
+  it.todo('Cleans up snap lines when cancelled')
+  it.todo('Cleans up snap lines when completed')
+  it.todo('Cleans up snap lines when starting to clone / not clone')
+})

packages/tldraw/src/state/session/sessions/translate/translate.session.ts

@@ -1,5 +1,5 @@
 /* eslint-disable @typescript-eslint/no-non-null-assertion */
-import { TLPageState, Utils } from '@tldraw/core'
+import { TLPageState, Utils, TLBoundsWithCenter, TLSnapLine } from '@tldraw/core'
 import { Vec } from '@tldraw/vec'
 import {
   TLDrawShape,
@@ -11,19 +11,50 @@ import {
   ArrowShape,
   GroupShape,
   SessionType,
+  ArrowBinding,
 } from '~types'
+import { SNAP_DISTANCE } from '~state/constants'
 import { TLDR } from '~state/tldr'
 import type { Patch } from 'rko'
 
+type CloneInfo =
+  | {
+      state: 'empty'
+    }
+  | {
+      state: 'ready'
+      clones: TLDrawShape[]
+      clonedBindings: ArrowBinding[]
+    }
+
+type SnapInfo =
+  | {
+      state: 'empty'
+    }
+  | {
+      state: 'ready'
+      others: TLBoundsWithCenter[]
+      bounds: TLBoundsWithCenter[]
+    }
+
 export class TranslateSession implements Session {
   type = SessionType.Translate
   status = TLDrawStatus.Translating
   delta = [0, 0]
   prev = [0, 0]
+  prevPoint = [0, 0]
+  speed = 1
   origin: number[]
   snapshot: TranslateSnapshot
   isCloning = false
   isCreate: boolean
+  cloneInfo: CloneInfo = {
+    state: 'empty',
+  }
+  snapInfo: SnapInfo = {
+    state: 'empty',
+  }
+  snapLines: TLSnapLine[] = []
 
   constructor(data: Data, point: number[], isCreate = false) {
     this.origin = point
@@ -34,6 +65,8 @@ export class TranslateSession implements Session {
   start = (data: Data) => {
     const { bindingsToDelete } = this.snapshot
 
+    this.createSnapInfo(data)
+
     if (bindingsToDelete.length === 0) return data
 
     const nextBindings: Patch<Record<string, TLDrawBinding>> = {}
@@ -51,16 +84,30 @@ export class TranslateSession implements Session {
     }
   }
 
-  update = (data: Data, point: number[], shiftKey: boolean, altKey: boolean) => {
+  update = (data: Data, point: number[], shiftKey = false, altKey = false, metaKey = false) => {
-    const { selectedIds, initialParentChildren, clones, initialShapes, bindingsToDelete } =
+    const { selectedIds, initialParentChildren, initialShapes, bindingsToDelete } = this.snapshot
-      this.snapshot
 
     const { currentPageId } = data.appState
+
     const nextBindings: Patch<Record<string, TLDrawBinding>> = {}
+
     const nextShapes: Patch<Record<string, TLDrawShape>> = {}
+
     const nextPageState: Patch<TLPageState> = {}
 
-    const delta = Vec.sub(point, this.origin)
+    let delta = Vec.sub(point, this.origin)
+
+    let didChangeCloning = false
+
+    if (!this.isCreate) {
+      if (altKey && !this.isCloning) {
+        this.isCloning = true
+        didChangeCloning = true
+      } else if (!altKey && this.isCloning) {
+        this.isCloning = false
+        didChangeCloning = true
+      }
+    }
 
     if (shiftKey) {
       if (Math.abs(delta[0]) < Math.abs(delta[1])) {
@@ -70,15 +117,71 @@ export class TranslateSession implements Session {
       }
     }
 
-    const trueDelta = Vec.sub(delta, this.prev)
+    // Should we snap?
+
+    // Speed is used to decide which snap points to use. At a high
+    // speed, we don't use any snap points. At a low speed, we only
+    // allow center-to-center snap points. At very low speed, we
+    // enable all snap points (still preferring middle snaps). We're
+    // using an acceleration function here to smooth the changes in
+    // speed, but we also want the speed to accelerate faster than
+    // it decelerates.
+
+    const speed = Vec.dist(point, this.prevPoint)
+
+    this.prevPoint = point
+
+    const change = speed - this.speed
+
+    this.speed = this.speed + change * (change > 1 ? 0.5 : 0.15)
+
+    this.snapLines = []
+
+    if (!metaKey && this.speed < 4 && this.snapInfo.state === 'ready') {
+      const { zoom } = data.document.pageStates[currentPageId].camera
+
+      const bounds = Utils.getBoundsWithCenter(
+        Utils.translateBounds(this.snapshot.commonBounds, delta)
+      )
+
+      const snapResult = Utils.getSnapPoints(
+        bounds,
+        this.isCloning ? this.snapInfo.bounds : this.snapInfo.others,
+        SNAP_DISTANCE / zoom,
+        this.speed * zoom < 0.45
+      )
+
+      if (snapResult) {
+        this.snapLines = snapResult.snapLines
+        delta = Vec.sub(delta, snapResult?.offset)
+      }
+    }
+
+    // We've now calculated the "delta", or difference between the
+    // cursor's position (real or adjusted by snaps or axis locking)
+    // and the cursor's original position ("origin").
+
+    // The "movement" is the actual change of position between this
+    // computed position and the previous computed position.
+
+    const movement = Vec.sub(delta, this.prev)
 
-    this.delta = delta
     this.prev = delta
 
     // If cloning...
-    if (!this.isCreate && altKey) {
+    if (this.isCloning) {
       // Not Cloning -> Cloning
-      if (!this.isCloning) {
+      if (didChangeCloning) {
+        if (this.cloneInfo.state === 'empty') {
+          this.createCloneInfo(data)
+        }
+
+        if (this.cloneInfo.state === 'empty') {
+          throw Error
+        }
+
+        const { clones, clonedBindings } = this.cloneInfo
+
         this.isCloning = true
 
         // Put back any bindings we deleted
@@ -109,7 +212,7 @@ export class TranslateSession implements Session {
         })
 
         // Add the cloned bindings
-        for (const binding of this.snapshot.clonedBindings) {
+        for (const binding of clonedBindings) {
           nextBindings[binding.id] = binding
         }
 
@@ -117,6 +220,10 @@ export class TranslateSession implements Session {
         nextPageState.selectedIds = clones.map((clone) => clone.id)
       }
 
+      if (this.cloneInfo.state === 'empty') throw Error
+
+      const { clones } = this.cloneInfo
+
       // Either way, move the clones
       clones.forEach((clone) => {
         const current = (nextShapes[clone.id] ||
@@ -126,14 +233,18 @@ export class TranslateSession implements Session {
 
         nextShapes[clone.id] = {
           ...nextShapes[clone.id],
-          point: Vec.round(Vec.add(current.point, trueDelta)),
+          point: Vec.round(Vec.add(current.point, movement)),
         }
       })
     } else {
       // If not cloning...
 
       // Cloning -> Not Cloning
-      if (this.isCloning) {
+      if (didChangeCloning) {
+        if (this.cloneInfo.state === 'empty') throw Error
+
+        const { clones, clonedBindings } = this.cloneInfo
+
         this.isCloning = false
 
         // Delete the bindings
@@ -159,7 +270,7 @@ export class TranslateSession implements Session {
         })
 
         // Delete the cloned bindings
-        for (const binding of this.snapshot.clonedBindings) {
+        for (const binding of clonedBindings) {
           nextBindings[binding.id] = undefined
         }
 
@@ -176,12 +287,15 @@ export class TranslateSession implements Session {
 
         nextShapes[shape.id] = {
           ...nextShapes[shape.id],
-          point: Vec.round(Vec.add(current.point, trueDelta)),
+          point: Vec.round(Vec.add(current.point, movement)),
         }
       })
     }
 
     return {
+      appState: {
+        snapLines: this.snapLines,
+      },
       document: {
         pages: {
           [data.appState.currentPageId]: {
@@ -197,7 +311,7 @@ export class TranslateSession implements Session {
   }
 
   cancel = (data: Data) => {
-    const { initialShapes, clones, clonedBindings, bindingsToDelete } = this.snapshot
+    const { initialShapes, bindingsToDelete } = this.snapshot
 
     const nextBindings: Record<string, Partial<TLDrawBinding> | undefined> = {}
     const nextShapes: Record<string, Partial<TLDrawShape> | undefined> = {}
@@ -218,13 +332,19 @@ export class TranslateSession implements Session {
       nextPageState.selectedIds = this.snapshot.selectedIds
     }
 
+    if (this.cloneInfo.state === 'ready') {
+      const { clones, clonedBindings } = this.cloneInfo
       // Delete clones
       clones.forEach((clone) => (nextShapes[clone.id] = undefined))
 
       // Delete cloned bindings
       clonedBindings.forEach((binding) => (nextBindings[binding.id] = undefined))
+    }
 
     return {
+      appState: {
+        snapLines: [],
+      },
       document: {
         pages: {
           [data.appState.currentPageId]: {
@@ -242,8 +362,7 @@ export class TranslateSession implements Session {
   complete(data: Data): TLDrawCommand {
     const pageId = data.appState.currentPageId
 
-    const { initialShapes, initialParentChildren, bindingsToDelete, clones, clonedBindings } =
+    const { initialShapes, initialParentChildren, bindingsToDelete } = this.snapshot
-      this.snapshot
 
     const beforeBindings: Patch<Record<string, TLDrawBinding>> = {}
     const beforeShapes: Patch<Record<string, TLDrawShape>> = {}
@@ -252,6 +371,13 @@ export class TranslateSession implements Session {
     const afterShapes: Patch<Record<string, TLDrawShape>> = {}
 
     if (this.isCloning) {
+      if (this.cloneInfo.state === 'empty') {
+        this.createCloneInfo(data)
+      }
+
+      if (this.cloneInfo.state !== 'ready') throw Error
+      const { clones, clonedBindings } = this.cloneInfo
+
       // Update the clones
       clones.forEach((clone) => {
         beforeShapes[clone.id] = undefined
@@ -331,6 +457,9 @@ export class TranslateSession implements Session {
     return {
       id: 'translate',
       before: {
+        appState: {
+          snapLines: [],
+        },
         document: {
           pages: {
             [data.appState.currentPageId]: {
@@ -346,6 +475,9 @@ export class TranslateSession implements Session {
         },
       },
       after: {
+        appState: {
+          snapLines: [],
+        },
         document: {
           pages: {
             [data.appState.currentPageId]: {
@@ -362,34 +494,37 @@ export class TranslateSession implements Session {
       },
     }
   }
+
+  private createSnapInfo = async (data: Data) => {
+    const { currentPageId } = data.appState
+    const page = data.document.pages[currentPageId]
+    const { selectedIds } = data.document.pageStates[currentPageId]
+
+    const allBounds: TLBoundsWithCenter[] = []
+    const otherBounds: TLBoundsWithCenter[] = []
+
+    Object.values(page.shapes).forEach((shape) => {
+      const bounds = Utils.getBoundsWithCenter(TLDR.getBounds(shape))
+      allBounds.push(bounds)
+      if (!selectedIds.includes(shape.id)) {
+        otherBounds.push(bounds)
+      }
+    })
+
+    this.snapInfo = {
+      state: 'ready',
+      bounds: allBounds,
+      others: otherBounds,
+    }
   }
 
-// eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
+  private createCloneInfo = (data: Data) => {
-export function getTranslateSnapshot(data: Data) {
+    // Create clones when as they're needed.
+    // Consider doing this work in a worker.
+
     const { currentPageId } = data.appState
-  const selectedIds = TLDR.getSelectedIds(data, currentPageId)
+    const page = data.document.pages[currentPageId]
-  const page = TLDR.getPage(data, currentPageId)
+    const { selectedIds, shapesToMove, initialParentChildren } = this.snapshot
-
-  const selectedShapes = selectedIds.flatMap((id) => TLDR.getShape(data, id, currentPageId))
-
-  const hasUnlockedShapes = selectedShapes.length > 0
-
-  const shapesToMove: TLDrawShape[] = selectedShapes
-    .filter((shape) => !selectedIds.includes(shape.parentId))
-    .flatMap((shape) => {
-      return shape.children
-        ? [shape, ...shape.children!.map((childId) => TLDR.getShape(data, childId, currentPageId))]
-        : [shape]
-    })
-
-  const initialParentChildren: Record<string, string[]> = {}
-
-  Array.from(new Set(shapesToMove.map((s) => s.parentId)).values())
-    .filter((id) => id !== page.id)
-    .forEach((id) => {
-      const shape = TLDR.getShape(data, id, currentPageId)
-      initialParentChildren[id] = shape.children!
-    })
 
     const cloneMap: Record<string, string> = {}
     const clonedBindingsMap: Record<string, string> = {}
@@ -431,8 +566,6 @@ export function getTranslateSnapshot(data: Data) {
     // original shapes that were cloned, not their clones' ids.
     const clonedShapeIds = new Set(Object.keys(cloneMap))
 
-  const bindingsToDelete: TLDrawBinding[] = []
-
     // Create cloned bindings for shapes where both to and from shapes are selected
     // (if the user clones, then we will create a new binding for the clones)
     Object.values(page.bindings)
@@ -451,8 +584,6 @@ export function getTranslateSnapshot(data: Data) {
 
             clonedBindingsMap[binding.id] = cloneId
             clonedBindings.push(cloneBinding)
-        } else {
-          bindingsToDelete.push(binding)
           }
         }
       })
@@ -475,18 +606,69 @@ export function getTranslateSnapshot(data: Data) {
       }
     })
 
+    this.cloneInfo = {
+      state: 'ready',
+      clones,
+      clonedBindings,
+    }
+  }
+}
+
+// eslint-disable-next-line @typescript-eslint/explicit-module-boundary-types
+export function getTranslateSnapshot(data: Data) {
+  const { currentPageId } = data.appState
+  const selectedIds = TLDR.getSelectedIds(data, currentPageId)
+  const page = TLDR.getPage(data, currentPageId)
+
+  const selectedShapes = selectedIds.flatMap((id) => TLDR.getShape(data, id, currentPageId))
+
+  const hasUnlockedShapes = selectedShapes.length > 0
+
+  const shapesToMove: TLDrawShape[] = selectedShapes
+    .filter((shape) => !selectedIds.includes(shape.parentId))
+    .flatMap((shape) => {
+      return shape.children
+        ? [shape, ...shape.children!.map((childId) => TLDR.getShape(data, childId, currentPageId))]
+        : [shape]
+    })
+
+  const idsToMove = new Set(shapesToMove.map((shape) => shape.id))
+
+  const bindingsToDelete: ArrowBinding[] = []
+
+  Object.values(page.bindings)
+    .filter((binding) => idsToMove.has(binding.fromId) || idsToMove.has(binding.toId))
+    .forEach((binding) => {
+      if (idsToMove.has(binding.fromId)) {
+        if (!idsToMove.has(binding.toId)) {
+          bindingsToDelete.push(binding)
+        }
+      }
+    })
+
+  const initialParentChildren: Record<string, string[]> = {}
+
+  Array.from(new Set(shapesToMove.map((s) => s.parentId)).values())
+    .filter((id) => id !== page.id)
+    .forEach((id) => {
+      const shape = TLDR.getShape(data, id, currentPageId)
+      initialParentChildren[id] = shape.children!
+    })
+
+  const commonBounds = Utils.getCommonBounds(shapesToMove.map(TLDR.getBounds))
+
   return {
     selectedIds,
-    bindingsToDelete,
     hasUnlockedShapes,
     initialParentChildren,
+    shapesToMove,
+    bindingsToDelete,
+    commonBounds,
     initialShapes: shapesToMove.map(({ id, point, parentId }) => ({
       id,
       point,
       parentId,
     })),
-    clones,
-    clonedBindings,
   }
 }
 

packages/tldraw/src/state/tlstate.ts

@@ -44,6 +44,7 @@ import { ArgsOfType, getSession } from './session'
 import { sample, USER_COLORS } from './utils'
 import { createTools, ToolType } from './tool'
 import type { BaseTool } from './tool/BaseTool'
+import * as constants from './constants'
 
 const uuid = Utils.uniqueId()
 
@@ -1392,7 +1393,10 @@ export class TLDrawState extends StateManager<Data> {
     const bounds = Utils.getCommonBounds(shapes.map(TLDR.getBounds))
 
     let zoom = TLDR.getCameraZoom(
-      Math.min((this.bounds.width - 128) / bounds.width, (this.bounds.height - 128) / bounds.height)
+      Math.min(
+        (this.bounds.width - constants.FIT_TO_SCREEN_PADDING) / bounds.width,
+        (this.bounds.height - constants.FIT_TO_SCREEN_PADDING) / bounds.height
+      )
     )
 
     zoom =
@@ -1419,7 +1423,10 @@ export class TLDrawState extends StateManager<Data> {
     const bounds = TLDR.getSelectedBounds(this.state)
 
     let zoom = TLDR.getCameraZoom(
-      Math.min((this.bounds.width - 128) / bounds.width, (this.bounds.height - 128) / bounds.height)
+      Math.min(
+        (this.bounds.width - constants.FIT_TO_SCREEN_PADDING) / bounds.width,
+        (this.bounds.height - constants.FIT_TO_SCREEN_PADDING) / bounds.height
+      )
     )
 
     zoom =
@@ -1645,10 +1652,13 @@ export class TLDrawState extends StateManager<Data> {
    * updateSession.
    * @param args The arguments of the current session's update method.
    */
-  updateSession = (point: number[], shiftKey = false, altKey = false, metaKey = false): this => {
+  updateSession = <T extends Session>(...args: ExceptFirst<Parameters<T['update']>>): this => {
     const { session } = this
     if (!session) return this
-    const patch = session.update(this.state, point, shiftKey, altKey, metaKey)
+
+    // eslint-disable-next-line @typescript-eslint/ban-ts-comment
+    // @ts-ignore
+    const patch = session.update(this.state, ...args)
     if (!patch) return this
     return this.patchState(patch, `session:${session?.constructor.name}`)
   }
@@ -1713,6 +1723,7 @@ export class TLDrawState extends StateManager<Data> {
         // the shape we just created.
         result.before = {
           appState: {
+            ...result.before.appState,
             status: TLDrawStatus.Idle,
           },
           document: {
@@ -1741,6 +1752,7 @@ export class TLDrawState extends StateManager<Data> {
       }
 
       result.after.appState = {
+        ...result.after.appState,
         status: TLDrawStatus.Idle,
       }
 
@@ -2373,6 +2385,23 @@ export class TLDrawState extends StateManager<Data> {
     return Vec.round([this.bounds.width / 2, this.bounds.height / 2])
   }
 
+  get viewport() {
+    const { camera } = this.pageState
+    const { width, height } = this.bounds
+
+    const [minX, minY] = Vec.sub(Vec.div([0, 0], camera.zoom), camera.point)
+    const [maxX, maxY] = Vec.sub(Vec.div([width, height], camera.zoom), camera.point)
+
+    return {
+      minX,
+      minY,
+      maxX,
+      maxY,
+      height: maxX - minX,
+      width: maxY - minY,
+    }
+  }
+
   static version = 10.1
 
   static defaultDocument: TLDrawDocument = {
@@ -2420,6 +2449,7 @@ export class TLDrawState extends StateManager<Data> {
       isStyleOpen: false,
       isEmptyCanvas: false,
       status: TLDrawStatus.Idle,
+      snapLines: [],
     },
     document: TLDrawState.defaultDocument,
     room: {

packages/tldraw/src/types.ts

@@ -1,6 +1,6 @@
 /* eslint-disable @typescript-eslint/no-explicit-any */
 /* eslint-disable @typescript-eslint/ban-types */
-import type { TLBinding, TLShapeProps } from '@tldraw/core'
+import type { TLBinding, TLShapeProps, TLSnapLine } from '@tldraw/core'
 import type { TLShape, TLShapeUtil, TLHandle } from '@tldraw/core'
 import type { TLPage, TLUser, TLPageState } from '@tldraw/core'
 import type { StoreApi } from 'zustand'
@@ -63,6 +63,7 @@ export interface Data {
     isStyleOpen: boolean
     isEmptyCanvas: boolean
     status: string
+    snapLines: TLSnapLine[]
   }
   document: TLDrawDocument
   room?: {
@@ -105,9 +106,9 @@ export abstract class Session {
   abstract update: (
     data: Readonly<Data>,
     point: number[],
-    shiftKey: boolean,
+    shiftKey?: boolean,
-    altKey: boolean,
+    altKey?: boolean,
-    metaKey: boolean
+    metaKey?: boolean
   ) => TLDrawPatch | undefined
   abstract complete: (data: Readonly<Data>) => TLDrawPatch | TLDrawCommand | undefined
   abstract cancel: (data: Readonly<Data>) => TLDrawPatch | undefined

packages/vec/package.json

@@ -39,7 +39,7 @@
     "@types/node": "^16.7.10",
     "@typescript-eslint/eslint-plugin": "^4.30.0",
     "@typescript-eslint/parser": "^4.30.0",
-    "esbuild": "^0.12.24",
+    "esbuild": "^0.13.8",
     "eslint": "^7.32.0",
     "lerna": "^4.0.0",
     "ts-node": "^10.2.1",

yarn.lock

@@ -6319,10 +6319,113 @@ es6-promisify@^5.0.0:
   dependencies:
     es6-promise "^4.0.3"
 
-esbuild@^0.12.24, esbuild@^0.12.26:
+esbuild-android-arm64@0.13.8:
-  version "0.12.28"
+  version "0.13.8"
-  resolved "https://registry.yarnpkg.com/esbuild/-/esbuild-0.12.28.tgz#84da0d2a0d0dee181281545271e0d65cf6fab1ef"
+  resolved "https://registry.yarnpkg.com/esbuild-android-arm64/-/esbuild-android-arm64-0.13.8.tgz#c20e875c3c98164b1ffba9b28637bdf96f5e9e7c"
-  integrity sha512-pZ0FrWZXlvQOATlp14lRSk1N9GkeJ3vLIwOcUoo3ICQn9WNR4rWoNi81pbn6sC1iYUy7QPqNzI3+AEzokwyVcA==
+  integrity sha512-AilbChndywpk7CdKkNSZ9klxl+9MboLctXd9LwLo3b0dawmOF/i/t2U5d8LM6SbT1Xw36F8yngSUPrd8yPs2RA==
+
+esbuild-darwin-64@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-darwin-64/-/esbuild-darwin-64-0.13.8.tgz#f46e6b471ddbf62265234808a6a1aa91df18a417"
+  integrity sha512-b6sdiT84zV5LVaoF+UoMVGJzR/iE2vNUfUDfFQGrm4LBwM/PWXweKpuu6RD9mcyCq18cLxkP6w/LD/w9DtX3ng==
+
+esbuild-darwin-arm64@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-darwin-arm64/-/esbuild-darwin-arm64-0.13.8.tgz#a991157a6013facd4f2e14159b7da52626c90154"
+  integrity sha512-R8YuPiiJayuJJRUBG4H0VwkEKo6AvhJs2m7Tl0JaIer3u1FHHXwGhMxjJDmK+kXwTFPriSysPvcobXC/UrrZCQ==
+
+esbuild-freebsd-64@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-freebsd-64/-/esbuild-freebsd-64-0.13.8.tgz#301601d2e443ad458960e359b402a17d9500be9d"
+  integrity sha512-zBn6urrn8FnKC+YSgDxdof9jhPCeU8kR/qaamlV4gI8R3KUaUK162WYM7UyFVAlj9N0MyD3AtB+hltzu4cysTw==
+
+esbuild-freebsd-arm64@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-freebsd-arm64/-/esbuild-freebsd-arm64-0.13.8.tgz#039a63acc12ec0892006c147ea221e55f9125a9f"
+  integrity sha512-pWW2slN7lGlkx0MOEBoUGwRX5UgSCLq3dy2c8RIOpiHtA87xAUpDBvZK10MykbT+aMfXc0NI2lu1X+6kI34xng==
+
+esbuild-linux-32@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-linux-32/-/esbuild-linux-32-0.13.8.tgz#c537b67d7e694b60bfa2786581412838c6ba0284"
+  integrity sha512-T0I0ueeKVO/Is0CAeSEOG9s2jeNNb8jrrMwG9QBIm3UU18MRB60ERgkS2uV3fZ1vP2F8i3Z2e3Zju4lg9dhVmw==
+
+esbuild-linux-64@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-linux-64/-/esbuild-linux-64-0.13.8.tgz#0092fc8a064001a777bfa0e3b425bb8be8f96e6a"
+  integrity sha512-Bm8SYmFtvfDCIu9sjKppFXzRXn2BVpuCinU1ChTuMtdKI/7aPpXIrkqBNOgPTOQO9AylJJc1Zw6EvtKORhn64w==
+
+esbuild-linux-arm64@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-linux-arm64/-/esbuild-linux-arm64-0.13.8.tgz#5cd3f2bb924212971482e8dbc25c4afd09b28110"
+  integrity sha512-X4pWZ+SL+FJ09chWFgRNO3F+YtvAQRcWh0uxKqZSWKiWodAB20flsW/OWFYLXBKiVCTeoGMvENZS/GeVac7+tQ==
+
+esbuild-linux-arm@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-linux-arm/-/esbuild-linux-arm-0.13.8.tgz#ad634f96bf2975536907aeb9fdb75a3194f4ddce"
+  integrity sha512-4/HfcC40LJ4GPyboHA+db0jpFarTB628D1ifU+/5bunIgY+t6mHkJWyxWxAAE8wl/ZIuRYB9RJFdYpu1AXGPdg==
+
+esbuild-linux-mips64le@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-linux-mips64le/-/esbuild-linux-mips64le-0.13.8.tgz#57857edfebf9bf65766dc8be1637f2179c990572"
+  integrity sha512-o7e0D+sqHKT31v+mwFircJFjwSKVd2nbkHEn4l9xQ1hLR+Bv8rnt3HqlblY3+sBdlrOTGSwz0ReROlKUMJyldA==
+
+esbuild-linux-ppc64le@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-linux-ppc64le/-/esbuild-linux-ppc64le-0.13.8.tgz#fdb82a059a5b86bb10fb42091b4ebcf488b9cd46"
+  integrity sha512-eZSQ0ERsWkukJp2px/UWJHVNuy0lMoz/HZcRWAbB6reoaBw7S9vMzYNUnflfL3XA6WDs+dZn3ekHE4Y2uWLGig==
+
+esbuild-netbsd-64@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-netbsd-64/-/esbuild-netbsd-64-0.13.8.tgz#d7879e7123d3b2c04754ece8bd061aa6866deeff"
+  integrity sha512-gZX4kP7gVvOrvX0ZwgHmbuHczQUwqYppxqtoyC7VNd80t5nBHOFXVhWo2Ad/Lms0E8b+wwgI/WjZFTCpUHOg9Q==
+
+esbuild-openbsd-64@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-openbsd-64/-/esbuild-openbsd-64-0.13.8.tgz#88b280b6cb0a3f6adb60abf27fc506c506a35cf0"
+  integrity sha512-afzza308X4WmcebexbTzAgfEWt9MUkdTvwIa8xOu4CM2qGbl2LanqEl8/LUs8jh6Gqw6WsicEK52GPrS9wvkcw==
+
+esbuild-sunos-64@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-sunos-64/-/esbuild-sunos-64-0.13.8.tgz#229ae7c7703196a58acd0f0291ad9bebda815d63"
+  integrity sha512-mWPZibmBbuMKD+LDN23LGcOZ2EawMYBONMXXHmbuxeT0XxCNwadbCVwUQ/2p5Dp5Kvf6mhrlIffcnWOiCBpiVw==
+
+esbuild-windows-32@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-windows-32/-/esbuild-windows-32-0.13.8.tgz#892d093e32a21c0c9135e5a0ffdc380aeb70e763"
+  integrity sha512-QsZ1HnWIcnIEApETZWw8HlOhDSWqdZX2SylU7IzGxOYyVcX7QI06ety/aDcn437mwyO7Ph4RrbhB+2ntM8kX8A==
+
+esbuild-windows-64@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-windows-64/-/esbuild-windows-64-0.13.8.tgz#7defd8d79ae3bb7e6f53b65a7190be7daf901686"
+  integrity sha512-76Fb57B9eE/JmJi1QmUW0tRLQZfGo0it+JeYoCDTSlbTn7LV44ecOHIMJSSgZADUtRMWT9z0Kz186bnaB3amSg==
+
+esbuild-windows-arm64@0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild-windows-arm64/-/esbuild-windows-arm64-0.13.8.tgz#e59ae004496fd8a5ab67bfc7945a2e47480d6fb9"
+  integrity sha512-HW6Mtq5eTudllxY2YgT62MrVcn7oq2o8TAoAvDUhyiEmRmDY8tPwAhb1vxw5/cdkbukM3KdMYtksnUhF/ekWeg==
+
+esbuild@^0.13.8:
+  version "0.13.8"
+  resolved "https://registry.yarnpkg.com/esbuild/-/esbuild-0.13.8.tgz#bd7cc51b881ab067789f88e17baca74724c1ec4f"
+  integrity sha512-A4af7G7YZLfG5OnARJRMtlpEsCkq/zHZQXewgPA864l9D6VjjbH1SuFYK/OSV6BtHwDGkdwyRrX0qQFLnMfUcw==
+  optionalDependencies:
+    esbuild-android-arm64 "0.13.8"
+    esbuild-darwin-64 "0.13.8"
+    esbuild-darwin-arm64 "0.13.8"
+    esbuild-freebsd-64 "0.13.8"
+    esbuild-freebsd-arm64 "0.13.8"
+    esbuild-linux-32 "0.13.8"
+    esbuild-linux-64 "0.13.8"
+    esbuild-linux-arm "0.13.8"
+    esbuild-linux-arm64 "0.13.8"
+    esbuild-linux-mips64le "0.13.8"
+    esbuild-linux-ppc64le "0.13.8"
+    esbuild-netbsd-64 "0.13.8"
+    esbuild-openbsd-64 "0.13.8"
+    esbuild-sunos-64 "0.13.8"
+    esbuild-windows-32 "0.13.8"
+    esbuild-windows-64 "0.13.8"
+    esbuild-windows-arm64 "0.13.8"
 
 escalade@^3.1.1:
   version "3.1.1"
@@ -7616,11 +7719,16 @@ idb-keyval@^5.1.3:
   dependencies:
     safari-14-idb-fix "^1.0.6"
 
-idb@^6.0.0, idb@^6.1.2:
+idb@^6.0.0:
   version "6.1.3"
   resolved "https://registry.yarnpkg.com/idb/-/idb-6.1.3.tgz#e6cd3b9c38f5c696a82a4b435754f3873c5a7891"
   integrity sha512-oIRDpVcs5KXpI1hRnTJUwkY63RB/7iqu9nSNuzXN8TLHjs7oO20IoPFbBTsqxIL5IjzIUDi+FXlVcK4zm26J8A==
 
+idb@^6.1.2:
+  version "6.1.4"
+  resolved "https://registry.yarnpkg.com/idb/-/idb-6.1.4.tgz#ec77519fe2591be616eaf3bbdedc3662bb558a99"
+  integrity sha512-DshI5yxIB3NYc47cPpfipYX8MSIgQPqVR+WoaGI9EDq6cnLGgGYR1fp6z8/Bq9vMS8Jq1bS3eWUgXpFO5+ypSA==
+
 ieee754@^1.1.4, ieee754@^1.2.1:
   version "1.2.1"
   resolved "https://registry.yarnpkg.com/ieee754/-/ieee754-1.2.1.tgz#8eb7a10a63fff25d15a57b001586d177d1b0d352"