introductory

The difficulties in

  • Multi-graphics management

    • generate
    • storage
    • The class classification
    • A unique identifier
    • Select the id
    • Zindex stack

  • The event

    • Click on the
    • Double click on the
    • Right click on the
    • Drag and drop
    • rolling

  • animation

    • requestAnimationFrame
    • Minute hand rendering
    • Multibody motion
    • Motion curve strategy model

  • Object collision

    • isPointInPath
    • isPointInStroke
    • Mathematics to pick up

Performance optimization

  • Frame render
  • Split screen rendering of multiple overlapping Canvas
  • Reasonable context assignment. It takes a lot of performance
  • Reduced rendering capacity, off-screen pre-cropping
  • Off-screen Render DrawImage
  • Complex pure computation is transferred to worker execution