tldraw_0/components/canvas/bounds/corner-handle.tsx

import useHandleEvents from "hooks/useBoundsHandleEvents"
import styled from "styles"
import { Corner, Bounds } from "types"

export default function CornerHandle({
  size,
  corner,
  bounds,
}: {
  size: number
  bounds: Bounds
  corner: Corner
}) {
  const events = useHandleEvents(corner)

  const isTop = corner === Corner.TopLeft || corner === Corner.TopRight
  const isLeft = corner === Corner.TopLeft || corner === Corner.BottomLeft

  return (
    <StyledCorner
      corner={corner}
      x={(isLeft ? 0 : bounds.width) - size / 2}
      y={(isTop ? 0 : bounds.height) - size / 2}
      width={size}
      height={size}
      {...events}
    />
  )
}

const StyledCorner = styled("rect", {
  stroke: "$bounds",
  fill: "#fff",
  zStrokeWidth: 2,
  variants: {
    corner: {
      [Corner.TopLeft]: { cursor: "nwse-resize" },
      [Corner.TopRight]: { cursor: "nesw-resize" },
      [Corner.BottomRight]: { cursor: "nwse-resize" },
      [Corner.BottomLeft]: { cursor: "nesw-resize" },
    },
  },
})