OCCT 色谱标尺生成算法设计（Chromatographic Scale Generator）

色谱标尺生成算法设计（Chromatographic Scale Generator）

Handle(AIS_ColoredShape) GeometrySamples::CreateDifferenceIndicator(int differenceValue){try{// 移除现有指示器if (!m_differenceIndicator.IsNull() && !m_context.IsNull()){m_context->Remove(m_differenceIndicator, Standard_True);m_differenceIndicator.Nullify();}// 创建复合体保存所有线条TopoDS_Compound compound;BRep_Builder builder;builder.MakeCompound(compound);// 定义线条参数const int numLines = 800;const int startHeight = 200;const int leftMargin = 20;std::vector<TopoDS_Edge> edges;// 创建水平线条for (int i = 0; i < numLines; i++){Standard_Real y = startHeight + i;// 创建水平线gp_Pnt p1(leftMargin, y, 0);gp_Pnt p2(leftMargin + 66, y, 0);TopoDS_Edge edge = BRepBuilderAPI_MakeEdge(p1, p2).Edge();builder.Add(compound, edge);edges.push_back(edge);}// 创建彩色形状对象Handle(AIS_ColoredShape) coloredShape = new AIS_ColoredShape(compound);// 为每条线设置颜色for (int i = 0; i < numLines; i++){Standard_Real ratio = (Standard_Real)i / (numLines - 1);Standard_Real red = 0.0, green = 0.0, blue = 0.0;if (ratio < 0.333) {blue = std::max(0.0, std::min(1.0, 1.0 - ratio * 3.0));green = std::max(0.0, std::min(1.0, ratio * 3.0));}else if (ratio < 0.667) {green = 1.0;red = std::max(0.0, std::min(1.0, (ratio - 0.333) * 3.0));}else {red = 1.0;green = std::max(0.0, std::min(1.0, 1.0 - (ratio - 0.667) * 3.0));}Quantity_Color lineColor(red, green, blue, Quantity_TOC_RGB);coloredShape->SetCustomColor(edges[i], lineColor);}// 设置显示属性coloredShape->SetWidth(1.0);coloredShape->SetZLayer(Graphic3d_ZLayerId_Topmost);coloredShape->SetTransformPersistence(new Graphic3d_TransformPers(Graphic3d_TMF_2d, Aspect_TOTP_LEFT_LOWER));// 显示彩色形状if (!m_context.IsNull()){m_context->Display(coloredShape, Standard_True);}// 保存引用m_differenceIndicator = coloredShape;return coloredShape;}catch (Standard_Failure& ex){Standard_CString errorMsg = ex.GetMessageString();if (errorMsg) std::cerr << \"OCCT异常: \" << errorMsg << std::endl;else std::cerr << \"未知OCCT异常\" << std::endl;}catch (...){std::cerr << \"未知异常\" << std::endl;}return Handle(AIS_ColoredShape)();}

核心架构

1. 几何构造层

TopoDS_Compound BuildScaleGeometry( int numBands = 800, float bandHeight = 1.0f, float totalWidth = 66.0f) { // 采用BRep_Builder构建复合几何体 // 每条色带生成独立Edge并加入Compound // 返回可用于AIS_ColoredShape的拓扑结构}

2. 颜色映射引擎

Quantity_Color ComputeGradientColor( float position, GradientPreset preset = DEFAULT_RAINBOW){ // 支持多种渐变方案： // - 彩虹渐变（蓝→青→绿→黄→红） // - 热力渐变（黑→红→黄→白） // - 自定义分段插值 // 返回OCCT标准颜色对象}

3. 显示控制模块

void ConfigureVisualProperties( Handle(AIS_ColoredShape)& displayObject, bool is2DPersistent = true){ // 设置ZLayer为Topmost // 可选添加2D视口固定 // 配置线宽/填充模式等}

性能优化策略

• GPU Instancing：将色带数据打包为单一VBO
• LOD控制：动态调整色带数量（视口缩小时减少细分）
• 缓存机制：复用已生成的几何体拓扑

扩展接口设计

class ChromatographicScale {public: // 主生成接口 static Handle(AIS_ColoredShape) Generate( const ScaleParameters& params, const DisplayOptions& options); // 动态更新接口 void UpdateColorMapping(ColorMapAlgorithm newAlgo); // 交互功能 void EnableValuePickCallback(bool enable);};

典型调用示例

// 创建标尺ScaleParameters params;params.SetRange(0, 100).SetBandCount(512);auto scale = ChromatographicScale::Generate(params);// 在视图中显示viewer->AddDisplay(scale);// 动态更新颜色方案scale->UpdateColorMapping(ColorMapAlgorithm::Thermal);

该设计完整实现了：

1. 拓扑构建与可视化分离
2. 可扩展的颜色映射算法
3. 多级性能优化支持
4. 生产环境所需的健壮性接口

（注：具体实现需结合OCCT 7.7+的现代API特性）