finishes rotation

components/canvas/bounds-bg.tsx

@@ -6,10 +6,14 @@ import styled from "styles"
 export default function BoundsBg() {
   const rBounds = useRef<SVGRectElement>(null)
   const bounds = useSelector((state) => state.values.selectedBounds)
-  const singleSelection = useSelector((s) => {
+
+  const rotation = useSelector((s) => {
     if (s.data.selectedIds.size === 1) {
+      const { shapes } = s.data.document.pages[s.data.currentPageId]
       const selected = Array.from(s.data.selectedIds.values())[0]
-      return s.data.document.pages[s.data.currentPageId].shapes[selected]
+      return shapes[selected].rotation
+    } else {
+      return 0
     }
   })
 
@@ -30,12 +34,9 @@ export default function BoundsBg() {
         rBounds.current.setPointerCapture(e.pointerId)
         state.send("POINTED_BOUNDS", inputs.pointerDown(e, "bounds"))
       }}
-      transform={
-        singleSelection &&
-        `rotate(${singleSelection.rotation * (180 / Math.PI)},${
-          minX + width / 2
-        }, ${minY + width / 2})`
-      }
+      transform={`rotate(${rotation * (180 / Math.PI)},${minX + width / 2}, ${
+        minY + height / 2
+      })`}
     />
   )
 }

components/canvas/bounds.tsx

@@ -6,15 +6,19 @@ import { TransformCorner, TransformEdge } from "types"
 import { lerp } from "utils/utils"
 
 export default function Bounds() {
-  const zoom = useSelector((state) => state.data.camera.zoom)
-  const bounds = useSelector((state) => state.values.selectedBounds)
-  const singleSelection = useSelector((s) => {
+  const isBrushing = useSelector((s) => s.isIn("brushSelecting"))
+  const zoom = useSelector((s) => s.data.camera.zoom)
+  const bounds = useSelector((s) => s.values.selectedBounds)
+
+  const rotation = useSelector((s) => {
     if (s.data.selectedIds.size === 1) {
+      const { shapes } = s.data.document.pages[s.data.currentPageId]
       const selected = Array.from(s.data.selectedIds.values())[0]
-      return s.data.document.pages[s.data.currentPageId].shapes[selected]
+      return shapes[selected].rotation
+    } else {
+      return 0
     }
   })
-  const isBrushing = useSelector((state) => state.isIn("brushSelecting"))
 
   if (!bounds) return null
 
@@ -26,12 +30,9 @@ export default function Bounds() {
   return (
     <g
       pointerEvents={isBrushing ? "none" : "all"}
-      transform={
-        singleSelection &&
-        `rotate(${singleSelection.rotation * (180 / Math.PI)},${
-          minX + width / 2
-        }, ${minY + width / 2})`
-      }
+      transform={`rotate(${rotation * (180 / Math.PI)},${minX + width / 2}, ${
+        minY + height / 2
+      })`}
     >
       <StyledBounds
         x={minX}

lib/shapes/circle.tsx

@@ -5,6 +5,7 @@ import { createShape } from "./index"
 import { boundsContained } from "utils/bounds"
 import { intersectCircleBounds } from "utils/intersections"
 import { pointInCircle } from "utils/hitTests"
+import { translateBounds } from "utils/utils"
 
 const circle = createShape<CircleShape>({
   boundsCache: new WeakMap([]),
@@ -33,27 +34,26 @@ const circle = createShape<CircleShape>({
   },
 
   getBounds(shape) {
-    if (this.boundsCache.has(shape)) {
-      return this.boundsCache.get(shape)
+    if (!this.boundsCache.has(shape)) {
+      const { radius } = shape
+
+      const bounds = {
+        minX: 0,
+        maxX: radius * 2,
+        minY: 0,
+        maxY: radius * 2,
+        width: radius * 2,
+        height: radius * 2,
+      }
+
+      this.boundsCache.set(shape, bounds)
     }
 
-    const {
-      point: [x, y],
-      radius,
-    } = shape
+    return translateBounds(this.boundsCache.get(shape), shape.point)
+  },
 
-    const bounds = {
-      minX: x,
-      maxX: x + radius * 2,
-      minY: y,
-      maxY: y + radius * 2,
-      width: radius * 2,
-      height: radius * 2,
-    }
-
-    this.boundsCache.set(shape, bounds)
-
-    return bounds
+  getRotatedBounds(shape) {
+    return this.getBounds(shape)
   },
 
   getCenter(shape) {

lib/shapes/dot.tsx

@@ -6,6 +6,7 @@ import { boundsContained } from "utils/bounds"
 import { intersectCircleBounds } from "utils/intersections"
 import styled from "styles"
 import { DotCircle } from "components/canvas/misc"
+import { translateBounds } from "utils/utils"
 
 const dot = createShape<DotShape>({
   boundsCache: new WeakMap([]),
@@ -33,26 +34,24 @@ const dot = createShape<DotShape>({
   },
 
   getBounds(shape) {
-    if (this.boundsCache.has(shape)) {
-      return this.boundsCache.get(shape)
+    if (!this.boundsCache.has(shape)) {
+      const bounds = {
+        minX: 0,
+        maxX: 1,
+        minY: 0,
+        maxY: 1,
+        width: 1,
+        height: 1,
+      }
+
+      this.boundsCache.set(shape, bounds)
     }
 
-    const {
-      point: [x, y],
-    } = shape
+    return translateBounds(this.boundsCache.get(shape), shape.point)
+  },
 
-    const bounds = {
-      minX: x,
-      maxX: x + 1,
-      minY: y,
-      maxY: y + 1,
-      width: 1,
-      height: 1,
-    }
-
-    this.boundsCache.set(shape, bounds)
-
-    return bounds
+  getRotatedBounds(shape) {
+    return this.getBounds(shape)
   },
 
   getCenter(shape) {

lib/shapes/ellipse.tsx

@@ -5,6 +5,7 @@ import { createShape } from "./index"
 import { boundsContained } from "utils/bounds"
 import { intersectEllipseBounds } from "utils/intersections"
 import { pointInEllipse } from "utils/hitTests"
+import { translateBounds } from "utils/utils"
 
 const ellipse = createShape<EllipseShape>({
   boundsCache: new WeakMap([]),
@@ -36,28 +37,26 @@ const ellipse = createShape<EllipseShape>({
   },
 
   getBounds(shape) {
-    if (this.boundsCache.has(shape)) {
-      return this.boundsCache.get(shape)
+    if (!this.boundsCache.has(shape)) {
+      const { radiusX, radiusY } = shape
+
+      const bounds = {
+        minX: 0,
+        maxX: radiusX * 2,
+        minY: 0,
+        maxY: radiusY * 2,
+        width: radiusX * 2,
+        height: radiusY * 2,
+      }
+
+      this.boundsCache.set(shape, bounds)
     }
 
-    const {
-      point: [x, y],
-      radiusX,
-      radiusY,
-    } = shape
+    return translateBounds(this.boundsCache.get(shape), shape.point)
+  },
 
-    const bounds = {
-      minX: x,
-      maxX: x + radiusX * 2,
-      minY: y,
-      maxY: y + radiusY * 2,
-      width: radiusX * 2,
-      height: radiusY * 2,
-    }
-
-    this.boundsCache.set(shape, bounds)
-
-    return bounds
+  getRotatedBounds(shape) {
+    return this.getBounds(shape)
   },
 
   getCenter(shape) {

lib/shapes/index.tsx

@@ -36,6 +36,9 @@ export interface ShapeUtility<K extends Shape> {
   // Get the bounds of the a shape.
   getBounds(this: ShapeUtility<K>, shape: K): Bounds
 
+  // Get the routated bounds of the a shape.
+  getRotatedBounds(this: ShapeUtility<K>, shape: K): Bounds
+
   // Get the center of the shape
   getCenter(this: ShapeUtility<K>, shape: K): number[]
 

lib/shapes/line.tsx

@@ -5,6 +5,7 @@ import { createShape } from "./index"
 import { boundsContained } from "utils/bounds"
 import { intersectCircleBounds } from "utils/intersections"
 import { DotCircle } from "components/canvas/misc"
+import { translateBounds } from "utils/utils"
 
 const line = createShape<LineShape>({
   boundsCache: new WeakMap([]),
@@ -41,26 +42,24 @@ const line = createShape<LineShape>({
   },
 
   getBounds(shape) {
-    if (this.boundsCache.has(shape)) {
-      return this.boundsCache.get(shape)
+    if (!this.boundsCache.has(shape)) {
+      const bounds = {
+        minX: 0,
+        maxX: 1,
+        minY: 0,
+        maxY: 1,
+        width: 1,
+        height: 1,
+      }
+
+      this.boundsCache.set(shape, bounds)
     }
 
-    const {
-      point: [x, y],
-    } = shape
+    return translateBounds(this.boundsCache.get(shape), shape.point)
+  },
 
-    const bounds = {
-      minX: x,
-      maxX: x + 1,
-      minY: y,
-      maxY: y + 1,
-      width: 1,
-      height: 1,
-    }
-
-    this.boundsCache.set(shape, bounds)
-
-    return bounds
+  getRotatedBounds(shape) {
+    return this.getBounds(shape)
   },
 
   getCenter(shape) {

lib/shapes/polyline.tsx

@@ -3,7 +3,12 @@ import * as vec from "utils/vec"
 import { PolylineShape, ShapeType } from "types"
 import { createShape } from "./index"
 import { intersectPolylineBounds } from "utils/intersections"
-import { boundsCollide, boundsContained } from "utils/bounds"
+import {
+  boundsCollide,
+  boundsContained,
+  boundsContainPolygon,
+} from "utils/bounds"
+import { getBoundsFromPoints, translateBounds } from "utils/utils"
 
 const polyline = createShape<PolylineShape>({
   boundsCache: new WeakMap([]),
@@ -29,33 +34,16 @@ const polyline = createShape<PolylineShape>({
   },
 
   getBounds(shape) {
-    if (this.boundsCache.has(shape)) {
-      return this.boundsCache.get(shape)
+    if (!this.boundsCache.has(shape)) {
+      const bounds = getBoundsFromPoints(shape.points)
+      this.boundsCache.set(shape, bounds)
     }
 
-    let minX = 0
-    let minY = 0
-    let maxX = 0
-    let maxY = 0
+    return translateBounds(this.boundsCache.get(shape), shape.point)
+  },
 
-    for (let [x, y] of shape.points) {
-      minX = Math.min(x, minX)
-      minY = Math.min(y, minY)
-      maxX = Math.max(x, maxX)
-      maxY = Math.max(y, maxY)
-    }
-
-    const bounds = {
-      minX: minX + shape.point[0],
-      minY: minY + shape.point[1],
-      maxX: maxX + shape.point[0],
-      maxY: maxY + shape.point[1],
-      width: maxX - minX,
-      height: maxY - minY,
-    }
-
-    this.boundsCache.set(shape, bounds)
-    return bounds
+  getRotatedBounds(shape) {
+    return this.getBounds(shape)
   },
 
   getCenter(shape) {
@@ -78,15 +66,23 @@ const polyline = createShape<PolylineShape>({
     return false
   },
 
-  hitTestBounds(this, shape, bounds) {
-    const shapeBounds = this.getBounds(shape)
+  hitTestBounds(this, shape, brushBounds) {
+    const b = this.getBounds(shape)
+    const center = [b.minX + b.width / 2, b.minY + b.height / 2]
+
+    const rotatedCorners = [
+      [b.minX, b.minY],
+      [b.maxX, b.minY],
+      [b.maxX, b.maxY],
+      [b.minX, b.maxY],
+    ].map((point) => vec.rotWith(point, center, shape.rotation))
+
     return (
-      boundsContained(shapeBounds, bounds) ||
-      (boundsCollide(shapeBounds, bounds) &&
-        intersectPolylineBounds(
-          shape.points.map((point) => vec.add(point, shape.point)),
-          bounds
-        ).length > 0)
+      boundsContainPolygon(brushBounds, rotatedCorners) ||
+      intersectPolylineBounds(
+        shape.points.map((point) => vec.add(point, shape.point)),
+        brushBounds
+      ).length > 0
     )
   },
 

lib/shapes/ray.tsx

@@ -5,6 +5,7 @@ import { createShape } from "./index"
 import { boundsContained } from "utils/bounds"
 import { intersectCircleBounds } from "utils/intersections"
 import { DotCircle } from "components/canvas/misc"
+import { translateBounds } from "utils/utils"
 
 const ray = createShape<RayShape>({
   boundsCache: new WeakMap([]),
@@ -40,27 +41,25 @@ const ray = createShape<RayShape>({
     )
   },
 
+  getRotatedBounds(shape) {
+    return this.getBounds(shape)
+  },
+
   getBounds(shape) {
-    if (this.boundsCache.has(shape)) {
-      return this.boundsCache.get(shape)
+    if (!this.boundsCache.has(shape)) {
+      const bounds = {
+        minX: 0,
+        maxX: 1,
+        minY: 0,
+        maxY: 1,
+        width: 1,
+        height: 1,
+      }
+
+      this.boundsCache.set(shape, bounds)
     }
 
-    const {
-      point: [x, y],
-    } = shape
-
-    const bounds = {
-      minX: x,
-      maxX: x + 8,
-      minY: y,
-      maxY: y + 8,
-      width: 8,
-      height: 8,
-    }
-
-    this.boundsCache.set(shape, bounds)
-
-    return bounds
+    return translateBounds(this.boundsCache.get(shape), shape.point)
   },
 
   getCenter(shape) {

lib/shapes/rectangle.tsx

@@ -2,7 +2,8 @@ import { v4 as uuid } from "uuid"
 import * as vec from "utils/vec"
 import { RectangleShape, ShapeType } from "types"
 import { createShape } from "./index"
-import { boundsContained, boundsCollide } from "utils/bounds"
+import { boundsCollidePolygon, boundsContainPolygon } from "utils/bounds"
+import { getBoundsFromPoints, rotateBounds, translateBounds } from "utils/utils"
 
 const rectangle = createShape<RectangleShape>({
   boundsCache: new WeakMap([]),
@@ -31,31 +32,40 @@ const rectangle = createShape<RectangleShape>({
   },
 
   getBounds(shape) {
-    if (this.boundsCache.has(shape)) {
-      return this.boundsCache.get(shape)
+    if (!this.boundsCache.has(shape)) {
+      const [width, height] = shape.size
+      const bounds = {
+        minX: 0,
+        maxX: width,
+        minY: 0,
+        maxY: height,
+        width,
+        height,
+      }
+
+      this.boundsCache.set(shape, bounds)
     }
 
-    const {
-      point: [x, y],
-      size: [width, height],
-    } = shape
+    return translateBounds(this.boundsCache.get(shape), shape.point)
+  },
 
-    const bounds = {
-      minX: x,
-      maxX: x + width,
-      minY: y,
-      maxY: y + height,
-      width,
-      height,
-    }
+  getRotatedBounds(shape) {
+    const b = this.getBounds(shape)
+    const center = [b.minX + b.width / 2, b.minY + b.height / 2]
 
-    this.boundsCache.set(shape, bounds)
+    // Rotate corners of the shape, then find the minimum among those points.
+    const rotatedCorners = [
+      [b.minX, b.minY],
+      [b.maxX, b.minY],
+      [b.maxX, b.maxY],
+      [b.minX, b.maxY],
+    ].map((point) => vec.rotWith(point, center, shape.rotation))
 
-    return bounds
+    return getBoundsFromPoints(rotatedCorners)
   },
 
   getCenter(shape) {
-    const bounds = this.getBounds(shape)
+    const bounds = this.getRotatedBounds(shape)
     return [bounds.minX + bounds.width / 2, bounds.minY + bounds.height / 2]
   },
 
@@ -64,10 +74,19 @@ const rectangle = createShape<RectangleShape>({
   },
 
   hitTestBounds(shape, brushBounds) {
-    const shapeBounds = this.getBounds(shape)
+    const b = this.getBounds(shape)
+    const center = [b.minX + b.width / 2, b.minY + b.height / 2]
+
+    const rotatedCorners = [
+      [b.minX, b.minY],
+      [b.maxX, b.minY],
+      [b.maxX, b.maxY],
+      [b.minX, b.maxY],
+    ].map((point) => vec.rotWith(point, center, shape.rotation))
+
     return (
-      boundsContained(shapeBounds, brushBounds) ||
-      boundsCollide(shapeBounds, brushBounds)
+      boundsContainPolygon(brushBounds, rotatedCorners) ||
+      boundsCollidePolygon(brushBounds, rotatedCorners)
     )
   },
 

state/commands/rotate.ts

@@ -16,16 +16,24 @@ export default function translateCommand(
       do(data) {
         const { shapes } = data.document.pages[after.currentPageId]
 
-        for (let { id, rotation } of after.shapes) {
-          shapes[id].rotation = rotation
+        for (let { id, point, rotation } of after.shapes) {
+          const shape = shapes[id]
+          shape.rotation = rotation
+          shape.point = point
         }
+
+        data.boundsRotation = after.boundsRotation
       },
       undo(data) {
         const { shapes } = data.document.pages[before.currentPageId]
 
-        for (let { id, rotation } of before.shapes) {
-          shapes[id].rotation = rotation
+        for (let { id, point, rotation } of before.shapes) {
+          const shape = shapes[id]
+          shape.rotation = rotation
+          shape.point = point
         }
+
+        data.boundsRotation = before.boundsRotation
       },
     })
   )

state/sessions/brush-session.ts

@@ -25,7 +25,7 @@ export default class BrushSession extends BaseSession {
   update = (data: Data, point: number[]) => {
     const { origin, snapshot } = this
 
-    const brushBounds = getBoundsFromPoints(origin, point)
+    const brushBounds = getBoundsFromPoints([origin, point])
 
     for (let { test, id } of snapshot.shapes) {
       if (test(brushBounds)) {

state/sessions/rotate-session.ts

@@ -18,24 +18,34 @@ export default class RotateSession extends BaseSession {
   }
 
   update(data: Data, point: number[]) {
-    const { currentPageId, center, shapes } = this.snapshot
+    const { currentPageId, boundsCenter, shapes } = this.snapshot
     const { document } = data
 
-    const a1 = vec.angle(center, this.origin)
-    const a2 = vec.angle(center, point)
+    const a1 = vec.angle(boundsCenter, this.origin)
+    const a2 = vec.angle(boundsCenter, point)
 
-    for (let { id, rotation } of shapes) {
+    data.boundsRotation =
+      (this.snapshot.boundsRotation + (a2 - a1)) % (Math.PI * 2)
+
+    for (let { id, center, offset, rotation } of shapes) {
       const shape = document.pages[currentPageId].shapes[id]
       shape.rotation = rotation + ((a2 - a1) % (Math.PI * 2))
+      const newCenter = vec.rotWith(
+        center,
+        boundsCenter,
+        (a2 - a1) % (Math.PI * 2)
+      )
+      shape.point = vec.sub(newCenter, offset)
     }
   }
 
   cancel(data: Data) {
     const { document } = data
 
-    for (let shape of this.snapshot.shapes) {
-      document.pages[this.snapshot.currentPageId].shapes[shape.id].rotation =
-        shape.rotation
+    for (let { id, point, rotation } of this.snapshot.shapes) {
+      const shape = document.pages[this.snapshot.currentPageId].shapes[id]
+      shape.rotation = rotation
+      shape.point = point
     }
   }
 
@@ -46,9 +56,10 @@ export default class RotateSession extends BaseSession {
 
 export function getRotateSnapshot(data: Data) {
   const {
+    boundsRotation,
     selectedIds,
-    document: { pages },
     currentPageId,
+    document: { pages },
   } = current(data)
 
   const shapes = Array.from(selectedIds.values()).map(
@@ -63,18 +74,28 @@ export function getRotateSnapshot(data: Data) {
   // The common (exterior) bounds of the selected shapes
   const bounds = getCommonBounds(...Object.values(shapesBounds))
 
-  const center = [
+  const boundsCenter = [
     bounds.minX + bounds.width / 2,
     bounds.minY + bounds.height / 2,
   ]
 
   return {
     currentPageId,
-    center,
-    shapes: shapes.map(({ id, rotation }) => ({
-      id,
-      rotation,
-    })),
+    boundsCenter,
+    boundsRotation,
+    shapes: shapes.map(({ id, point, rotation }) => {
+      const bounds = shapesBounds[id]
+      const offset = [bounds.width / 2, bounds.height / 2]
+      const center = vec.add(offset, [bounds.minX, bounds.minY])
+
+      return {
+        id,
+        point,
+        rotation,
+        offset,
+        center,
+      }
+    }),
   }
 }
 

state/state.ts

@@ -29,6 +29,7 @@ const initialData: Data = {
     zoom: 1,
   },
   brush: undefined,
+  boundsRotation: 0,
   pointedId: null,
   hoveredId: null,
   selectedIds: new Set([]),
@@ -180,6 +181,7 @@ const state = createState({
             brushSelecting: {
               onEnter: [
                 { unless: "isPressingShiftKey", do: "clearSelectedIds" },
+                "clearBoundsRotation",
                 "startBrushSession",
               ],
               on: {
@@ -708,6 +710,10 @@ const state = createState({
     restoreSavedData(data) {
       history.load(data)
     },
+
+    clearBoundsRotation(data) {
+      data.boundsRotation = 0
+    },
   },
   values: {
     selectedIds(data) {
@@ -726,12 +732,14 @@ const state = createState({
 
       if (selectedIds.size === 0) return null
 
-      if (selectedIds.size === 1 && !getShapeUtils(shapes[0]).canTransform) {
-        return null
+      if (selectedIds.size === 1) {
+        const shapeUtils = getShapeUtils(shapes[0])
+        if (!shapeUtils.canTransform) return null
+        return shapeUtils.getBounds(shapes[0])
       }
 
       return getCommonBounds(
-        ...shapes.map((shape) => getShapeUtils(shape).getBounds(shape))
+        ...shapes.map((shape) => getShapeUtils(shape).getRotatedBounds(shape))
       )
     },
   },

types.ts

@@ -18,6 +18,7 @@ export interface Data {
     zoom: number
   }
   brush?: Bounds
+  boundsRotation: number
   selectedIds: Set<string>
   pointedId?: string
   hoveredId?: string
@@ -168,6 +169,10 @@ export interface Bounds {
   height: number
 }
 
+export interface RotatedBounds extends Bounds {
+  rotation: number
+}
+
 export interface ShapeBounds extends Bounds {
   id: string
 }

utils/bounds.ts

@@ -1,4 +1,8 @@
 import { Bounds } from "types"
+import {
+  intersectPolygonBounds,
+  intersectPolylineBounds,
+} from "./intersections"
 
 /**
  * Get whether two bounds collide.
@@ -37,6 +41,23 @@ export function boundsContained(a: Bounds, b: Bounds) {
   return boundsContain(b, a)
 }
 
+/**
+ * Get whether a set of points are all contained by a bounding box.
+ * @returns
+ */
+export function boundsContainPolygon(a: Bounds, points: number[][]) {
+  return points.every((point) => pointInBounds(point, a))
+}
+
+/**
+ * Get whether a polygon collides a bounding box.
+ * @param points
+ * @param b
+ */
+export function boundsCollidePolygon(a: Bounds, points: number[][]) {
+  return intersectPolygonBounds(points, a).length > 0
+}
+
 /**
  * Get whether two bounds are identical.
  * @param a Bounds

utils/intersections.ts

@@ -342,3 +342,21 @@ export function intersectPolylineBounds(points: number[][], bounds: Bounds) {
 
   return intersections
 }
+
+export function intersectPolygonBounds(points: number[][], bounds: Bounds) {
+  const { minX, minY, width, height } = bounds
+  const intersections: Intersection[] = []
+
+  for (let i = 1; i < points.length + 1; i++) {
+    intersections.push(
+      ...intersectRectangleLineSegment(
+        [minX, minY],
+        [width, height],
+        points[i - 1],
+        points[i % points.length]
+      )
+    )
+  }
+
+  return intersections
+}

utils/utils.ts

@@ -41,21 +41,21 @@ export function getCommonBounds(...b: Bounds[]) {
   return bounds
 }
 
-export function getBoundsFromPoints(a: number[], b: number[]) {
-  const minX = Math.min(a[0], b[0])
-  const maxX = Math.max(a[0], b[0])
-  const minY = Math.min(a[1], b[1])
-  const maxY = Math.max(a[1], b[1])
+// export function getBoundsFromPoints(a: number[], b: number[]) {
+//   const minX = Math.min(a[0], b[0])
+//   const maxX = Math.max(a[0], b[0])
+//   const minY = Math.min(a[1], b[1])
+//   const maxY = Math.max(a[1], b[1])
 
-  return {
-    minX,
-    maxX,
-    minY,
-    maxY,
-    width: maxX - minX,
-    height: maxY - minY,
-  }
-}
+//   return {
+//     minX,
+//     maxX,
+//     minY,
+//     maxY,
+//     width: maxX - minX,
+//     height: maxY - minY,
+//   }
+// }
 
 // A helper for getting tangents.
 export function getCircleTangentToPoint(
@@ -962,3 +962,61 @@ export function vectorToPoint(point: number[] | Vector | undefined) {
   }
   return point
 }
+
+export function getBoundsFromPoints(points: number[][]): Bounds {
+  let minX = Infinity
+  let minY = Infinity
+  let maxX = -Infinity
+  let maxY = -Infinity
+
+  for (let [x, y] of points) {
+    minX = Math.min(x, minX)
+    minY = Math.min(y, minY)
+    maxX = Math.max(x, maxX)
+    maxY = Math.max(y, maxY)
+  }
+
+  return {
+    minX,
+    minY,
+    maxX,
+    maxY,
+    width: maxX - minX,
+    height: maxY - minY,
+  }
+}
+
+/**
+ * Move a bounding box without recalculating it.
+ * @param bounds
+ * @param delta
+ * @returns
+ */
+export function translateBounds(bounds: Bounds, delta: number[]) {
+  return {
+    minX: bounds.minX + delta[0],
+    minY: bounds.minY + delta[1],
+    maxX: bounds.maxX + delta[0],
+    maxY: bounds.maxY + delta[1],
+    width: bounds.width,
+    height: bounds.height,
+  }
+}
+
+export function rotateBounds(
+  bounds: Bounds,
+  center: number[],
+  rotation: number
+) {
+  const [minX, minY] = vec.rotWith([bounds.minX, bounds.minY], center, rotation)
+  const [maxX, maxY] = vec.rotWith([bounds.maxX, bounds.maxY], center, rotation)
+
+  return {
+    minX,
+    minY,
+    maxX,
+    maxY,
+    width: bounds.width,
+    height: bounds.height,
+  }
+}