orca/mobile/src/browser/browser-touch-geometry.test.ts

import { describe, expect, it } from 'vitest'
import {
  clampBrowserZoomState,
  computeBrowserFrameGeometry,
  mapScreenToBrowserPoint,
  readLocalTouchPoint
} from './browser-touch-geometry'

describe('browser touch geometry', () => {
  it('maps the visual center of a letterboxed desktop frame to the browser center', () => {
    const layout = { width: 390, height: 700 }
    const metadata = { deviceWidth: 1280, deviceHeight: 720 }
    const geometry = computeBrowserFrameGeometry(layout, metadata)

    expect(geometry).toMatchObject({
      renderedWidth: 390,
      offsetX: 0,
      sourceWidth: 1280,
      sourceHeight: 720
    })
    expect(
      mapScreenToBrowserPoint(
        195,
        geometry!.offsetY + geometry!.renderedHeight / 2,
        layout,
        metadata,
        { scale: 1, offsetX: 0, offsetY: 0 }
      )
    ).toEqual({ x: 640, y: 360 })
  })

  it('inverts pan and zoom around the rendered frame center', () => {
    const layout = { width: 390, height: 700 }
    const metadata = { deviceWidth: 1280, deviceHeight: 720 }
    const geometry = computeBrowserFrameGeometry(layout, metadata)!
    const zoom = { scale: 2, offsetX: -48, offsetY: 32 }
    const browserPoint = { x: 960, y: 540 }
    const localX = (browserPoint.x / metadata.deviceWidth) * geometry.renderedWidth
    const localY = (browserPoint.y / metadata.deviceHeight) * geometry.renderedHeight
    const screenX =
      geometry.offsetX +
      geometry.renderedWidth / 2 +
      zoom.offsetX +
      (localX - geometry.renderedWidth / 2) * zoom.scale
    const screenY =
      geometry.offsetY +
      geometry.renderedHeight / 2 +
      zoom.offsetY +
      (localY - geometry.renderedHeight / 2) * zoom.scale

    expect(mapScreenToBrowserPoint(screenX, screenY, layout, metadata, zoom)).toEqual(browserPoint)
  })

  it('rejects page-level touch coordinates instead of mixing coordinate spaces', () => {
    expect(readLocalTouchPoint({ pageX: 120, pageY: 240 })).toBeNull()
  })

  it('clamps zoom offsets after the viewport geometry changes', () => {
    const nextGeometry = computeBrowserFrameGeometry(
      { width: 390, height: 700 },
      { deviceWidth: 1280, deviceHeight: 720 }
    )!

    const clamped = clampBrowserZoomState(
      { scale: 3.5, offsetX: 300, offsetY: 500 },
      nextGeometry,
      1,
      3.5
    )

    expect(clamped.scale).toBe(3.5)
    expect(clamped.offsetX).toBe(300)
    expect(clamped.offsetY).toBeCloseTo(33.90625)
  })
})