学期与寒假学习总结

class GraphicsTool : public Tool {
    // 图形工具基类
    void paint(QPainter *painter) override;
};

class RectangleTool : public GraphicsTool {
    // 矩形工具
    void createPath(QPainterPath &path, const QRectF &rect);
};
class EllipseTool : public RectangleTool { /* 椭圆 */ };
class PolygonTool : public RectangleTool { /* 多边形 */ };
class StarTool : public RectangleTool { /* 星形 */ };

class PenTool : public PathTool { /* 钢笔工具 - 贝塞尔 */ };
class PencilTool : public PathTool { /* 铅笔工具 - 自由绘制 */ };
class SplineTool : public PathTool { /* 样条工具 - B样条 */ };

void Bezier::splitAt(qreal t, Bezier *left, Bezier *right) const {
    // de Casteljau 算法实现曲线分割
    left->x1 = x1;
    left->x2 = x1 + t * (x2 - x1);
    left->x3 = x2 + t * (x3 - x2);
    right->x3 = x3 + t * (x4 - x3);
    right->x4 = x4;
    
    right->x2 = left->x3 + t * (right->x3 - left->x3);
    left->x3 = left->x2 + t * (left->x3 - left->x2);
    
    // 中间连接点
    left->x4 = right->x1 = left->x3 + t * (right->x2 - left->x3);
}

QPointF Bezier::pointAt(qreal t) const {
    qreal a, b, c, d;
    coefficients(t, a, b, c, d);
    return QPointF(a*x1 + b*x2 + c*x3 + d*x4,
                   a*y1 + b*y2 + c*y3 + d*y4);
}

class SplineCurve2D : public SplineCurve {
    // 点集插值生成B样条
    bool interpolate(const double *points, int count,
        int flag = Open,             // Open/Closed/Periodic
        int parametrization = Chord, // 弦长参数化
        int order = Cubic);          // 三次样条
    
    // 转换为Bezier序列便于渲染
    bool convertToBeziers();
};

void SplineToolPrivate::updatePath() {
    SplineCurve2D curve;
    curve.interpolate(&samples[0].rx(), count, 
        closedFlag, SplineCurve::Chord);
    curve.convertToBeziers();
}

class OrthoSnapper {
    // 添加对齐目标
    void addTarget(const QPointF &point);
    void addTarget(const QRectF &rect);
    
    // 执行吸附
    void snapPoint(const QPointF &p);
    void snapRect(const QRectF &r);
    
    // 获取结果
    bool hasX() const;
    qreal deltaX() const;
    qreal targetX() const;
};

// 使用示例
OrthoSnapper snapper(5.0);
snapper.addTarget(otherRect);
snapper.snapPoint(currentPos);
if (snapper.hasX()) { /* 绘制对齐线 */ }