QML 3D曲面图(Surface3D)技术

3D曲面图是科学计算和工程可视化中常用的图表类型，它通过起伏的曲面展示二维数据的变化趋势。Qt Data Visualization 模块中的 Surface3D 类型提供了强大的曲面可视化能力。

Surface3D 核心属性与方法

表：Surface3D主要属性与方法

属性/方法	类型	描述	示例
`width`	real	曲面图宽度	`width: parent.width`
`height`	real	曲面图高度	`height: parent.height`
`selectionMode`	enum	选择模式(无/单项/行/列/行与列/切片)	`AbstractGraph3D.SelectionItem`
`shadowQuality`	enum	阴影质量(无/低/中/高/软低/软中/软高)	`AbstractGraph3D.ShadowQualityHigh`
`scene.activeCamera`	Q3DCamera	控制场景相机	`scene.activeCamera.xRotation: 60.0`
`theme`	Theme3D	设置图表主题	`theme: Theme3D { type: Theme3D.ThemeArmyBlue }`
`axisX`	Value3DAxis	X轴配置	`axisX: Value3DAxis { title: "经度"; min: -180; max: 180 }`
`axisY`	Value3DAxis	Y轴配置	`axisY: Value3DAxis { title: "高度"; min: 0; max: 10000 }`
`axisZ`	Value3DAxis	Z轴配置	`axisZ: Value3DAxis { title: "纬度"; min: -90; max: 90 }`
`flipHorizontalGrid`	bool	是否翻转水平网格	`flipHorizontalGrid: true`
`surfaceSeries`	list	曲面系列列表	`surfaceSeries: [heightMapSeries, temperatureSeries]`
`addSeries()`	method	添加曲面系列	`surface3D.addSeries(newSeries)`
`removeSeries()`	method	移除曲面系列	`surface3D.removeSeries(oldSeries)`
`release()`	method	释放资源	`Component.onDestruction: surface3D.release()`

基本曲面图实现

以下是一个完整的地形高度图示例，展示了如何使用Surface3D显示地理高程数据：

复制代码

import QtQuick
import QtQuick.Controls
import QtDataVisualization

Window {
    width: 640
    height: 480
    visible: true
    title: qsTr("Hello World")
    
    Surface3D {
        id: surfaceGraph
        anchors.fill: parent
        theme: Theme3D { type: Theme3D.ThemeArmyBlue }
        
        // 设置坐标轴
        axisX: ValueAxis3D {
            title: "东西方向 (km)"
        }
        
        axisY: ValueAxis3D {
            title: "高度 (m)"
            min: 30
            max: 200
        }
        
        axisZ: ValueAxis3D {
            title: "南北方向 (km)"
        }
        
        // 添加曲面系列
        Surface3DSeries {
            id: terrainSeries
            itemLabelFormat: "(@xLabel km, @zLabel km): @yLabel m"
            drawMode: Surface3DSeries.DrawSurfaceAndWireframe
            flatShadingEnabled: false
            
            // 使用高度图数据代理
            HeightMapSurfaceDataProxy {
                id: heightMapProxy
                heightMapFile: ":/layer_1.png"
            }
            
            // 自定义渐变颜色
            baseGradient: ColorGradient {
                ColorGradientStop { position: 0.0; color: "#0000ff" }  // 深水区
                ColorGradientStop { position: 0.2; color: "#00ffff" }  // 浅水区
                ColorGradientStop { position: 0.25; color: "#00aa00" } // 海滩
                ColorGradientStop { position: 0.5; color: "#ffff00" }  // 平原
                ColorGradientStop { position: 0.75; color: "#aa5500" } // 山地
                ColorGradientStop { position: 1.0; color: "#ffffff" } // 雪山
            }
            
            // 网格线样式
            wireframeColor: "#555555"
        }
        
        // 相机初始位置
        scene.activeCamera.xRotation: 20.0
        scene.activeCamera.yRotation: 45.0
    }
    
    // 控制面板
    Row {
        anchors.top: parent.top
        anchors.right: parent.right
        spacing: 10
        padding: 10
        
        Button {
            text: "俯视图"
            onClicked: {
                surfaceGraph.scene.activeCamera.cameraPreset = Camera3D.CameraPresetFrontHigh
            }
        }
        
        Button {
            text: "侧视图"
            onClicked: {
                surfaceGraph.scene.activeCamera.cameraPreset = Camera3D.CameraPresetRightLow
            }
        }
        
        Button {
            text: "等轴测"
            onClicked: {
                surfaceGraph.scene.activeCamera.cameraPreset = Camera3D.CameraPresetIsometricRight
            }
        }
        
        ComboBox {
            id: drawModeCombo
            model: ["Surface", "Wireframe", "Both"]
            onCurrentIndexChanged: {
                switch(currentIndex) {
                case 0: terrainSeries.drawMode = Surface3DSeries.DrawSurface; break;
                case 1: terrainSeries.drawMode = Surface3DSeries.DrawWireframe; break;
                case 2: terrainSeries.drawMode = Surface3DSeries.DrawSurfaceAndWireframe; break;
                }
            }
        }
    }
}