应用实例五：中心对称图案设计知识点：第二十三章《旋转》—— 中心对称。功能：一个画板，学生在左侧随意绘制图案，右侧实时生成关于中心点对称的图案。支持设计复杂的对称图形，培养美学与几何直觉。@Entry @Component struct SymmetryDesign { @State private paths: number[][] = [] @State private isDrawing: boolean = false @State private showGrid: boolean = true @State private brushSize: number = 3 @State private symmetryMode: number = 0 private settings: RenderingContextSettings = new RenderingContextSettings(true) private context: CanvasRenderingContext2D = new CanvasRenderingContext2D(this.settings) private readonly CENTER_X: number = 175 private readonly CENTER