D3 二维图表的绘制系列（二十九）径向树图

电玩女神 2023-10-10 08:54 18阅读 0赞

**上一篇： [关系图-弦图][-]**

**代码结构和初始化画布的Chart对象介绍，请先看 [这里][Link 1]**

**本图完整的源码地址： [这里][Link 2]**

## 1 图表效果 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pqd19weXRob24_size_16_color_FFFFFF_t_70]

## 2 数据 ##

{ 
        "name": "letter",
        "children": [
            { 
                "name": "a",
                "children": [
                    { 
                        "name": "a1",
                        "children": [
                            { "name": "a11", "value": 2},
                            { "name": "a12", "value": 3},
                            { "name": "a13", "value": 4},
                            { "name": "a14", "value": 5},
                            { "name": "a15", "value": 5},
                            { "name": "a16", "value": 7}
                        ]
                    }
                ]
            },
            { 
                "name": "b",
                "children": [
                    { 
                        "name": "b1",
                        "children": [
                            { "name": "b11", "value": 4},
                            { "name": "b12", "value": 2},
                            { "name": "b13", "value": 4},
                            { "name": "b14", "value": 4},
                            { "name": "b15", "value": 4},
                            { "name": "b16", "value": 4}
                        ]
                    },
                    { 
                        "name": "b2",
                        "children": [
                            { "name": "b21", "value": 4},
                            { "name": "b22", "value": 5},
                            { "name": "b23", "value": 4},
                            { "name": "b24", "value": 4}
                        ]
                    }
                ]
            },
            { 
                "name": "c",
                "children": [
                    { 
                        "name": "c1",
                        "children": [
                            { "name": "c11", "value": 6},
                            { "name": "c12", "value": 1}
                        ]
                    },
                    { 
    
                        "name": "c2",
                        "children": [
                            { "name": "c21", "value": 2},
                            { "name": "c22", "value": 3},
                            { "name": "c23", "value": 2},
                            { "name": "c24", "value": 3},
                            { "name": "c25", "value": 3},
                            { "name": "c26", "value": 3},
                            { "name": "c27", "value": 3},
                            { "name": "c28", "value": 3},
                            { "name": "c29", "value": 3}
                        ]
    
                    }
                ]
            }
    
        ]
    }

## 3 关键代码 ##

**导入数据**

d3.json('./data.json').then(function(data){ 
    ....

**一些样式配置参数，与基础树图类似**

const config = { 
            margins: { top: 80, left: 50, bottom: 20, right: 50},
            textColor: 'black',
            title: '径向树图',
            hoverColor: 'gray',
            animateDuration: 1000,
            pointSize: 5,
            pointFill: 'white',
            pointStroke: 'red',
            lineStroke: 'gray'
        }

**首先运用`d3.hierarchy`将数据转换为节点树，接着调用`d3.cluster`定义树图的布局信息，注意径向树图的`size`参数不再是长宽，而是弧度和半径**

/* ----------------------------数据转换------------------------ */
        chart._nodeId = 0;  //用于标识数据唯一性
    
        const root = d3.hierarchy(data);
    
        const generateTree = d3.cluster()
                        .nodeSize([10, 10])
                        .separation((a,b) => a.parent === b.parent ? 1 : 3)
                        .size([2 * Math.PI, d3.min([chart.getBodyWidth(), chart.getBodyHeight()]) / 2 * 0.8]);
    
        generateTree(root);

**接着渲染节点，节点由`circle`元素表示，与[基础树图][Link 3]的动画效果类似，要达到点击伸缩子树的功能，则需要对元素的`enter`和`exit`阶段添加过渡效果，`enter`时子树要从点击位置逐渐放大，而`exit`时子树要逐渐缩小到父节点的新位置**

/* ----------------------------渲染节点------------------------ */
        chart.renderNode = function(){ 
            let nodes = d3.select('.groups');
    
            if (nodes.empty()){ 
                nodes =  chart.body()
                            .append('g')
                            .attr('class', 'groups')
                            .attr('transform', 'translate(' + chart.getBodyWidth()/2 + ',' + chart.getBodyHeight()/2 + ')');
            }
    
            const groups = nodes
                            .selectAll('.g')
                            .data(root.descendants(),  (d) => d.id || (d.id = ++chart._nodeId));
    
            chart.groupsEnter = groups.enter()
                                        .append('g')
                                        .attr('class', (d) => 'g ' + d.data.name)
                                        .attr('transform', (d) => { 
                                            if (chart.first) return 'translate(' + chart.oldY * Math.cos(chart.oldX - Math.PI/2) + ',' + chart.oldY * Math.sin(chart.oldX - Math.PI/2) + ')';  //首次渲染，子树从（0，0）点开始放缩，否则，从点击位置开始放缩
                                        })
    
            chart.groupsEnter.append('circle')
                                .attr('r', config.pointSize)
                                .attr('cx', 0)
                                .attr('cy', 0)
                                .attr('stroke', config.pointStroke);
    
            chart.groupsEnter.merge(groups)
                                .transition().duration(config.animateDuration)
                                .attr('transform', (d) => { 
                                    return 'translate(' + d.y * Math.cos(d.x - Math.PI/2) + ',' + d.y * Math.sin(d.x - Math.PI/2) + ')';
                                })
                                .selectAll('circle')
                                    .attr('fill', (d) => d._children ? config.hoverColor: config.pointFill);
    
            groups.exit()
                    .attr('transform-origin', () => chart.targetNode.y * Math.cos(chart.targetNode.x - Math.PI/2) + ' ' + chart.targetNode.y * Math.sin(chart.targetNode.x - Math.PI/2))  //子树逐渐缩小到新位置
                    .transition().duration(config.animateDuration)
                    .attr('transform', 'scale(0.01)')
                    .remove();
        }

**渲染文本标签，其位置要根据节点是否有子树进行相应调整**

/* ----------------------------渲染文本标签------------------------ */
        chart.renderText = function(){ 
            d3.selectAll('.text').remove();
    
            const groups = d3.selectAll('.g');
    
            groups.append('text')
                    .attr('x', 0)
                    .attr('y', 0)
                    .attr('class', 'text')
                    .attr('text-anchor', 'middle')
                    .attr('dy', 3)
                    .text((d) => d.data.name)
                    .attr('transform', function(d){ 
                        const offsetRadius = d.children? -(this.getBBox().width + config.pointSize) : this.getBBox().width + config.pointSize;
                        const translate = d.depth === 0 ? 'translate(' +  this.getBBox().width/2 + ',' + -this.getBBox().height/2 + ')' : 'translate(' + offsetRadius * Math.cos(d.x - Math.PI/2) + ',' + offsetRadius * Math.sin(d.x - Math.PI/2) + ')';
                        let angle = (180 * d.x / Math.PI) % 360;
                        if (angle > 90 && angle < 270) { 
                            angle = angle + 180;
                        }
                        const rotate =  d.depth === 0 ? 'rotate(0)': 'rotate(' +  angle + ')';
                        return translate + ' ' + rotate;
                    });
        }

**渲染节点之间的连线，这里直接使用`d3.linkRadial`进行生成path，注意连线与节点类似，也需要相同的放缩过渡效果**

/* ----------------------------渲染连线------------------------ */
        chart.renderLines = function(){ 
    
            let link = d3.select('.links');
    
            if (link.empty()){ 
                link =  chart.body()
                            .insert('g', '.groups')
                            .attr('class', 'links')
                            .attr('transform', 'translate(' + chart.getBodyWidth()/2 + ',' + chart.getBodyHeight()/2 + ')')
            }
    
            const links = link
                            .selectAll('.link')
                            .data(root.links().map((item) => { 
                                item.id = item.source.id + '-' + item.target.id;   // 为链接添加id
                                return item;
                            }), (d) => d.id );
    
                links.enter()
                        .append('path')
                        .attr('class', 'link')
                        .attr('fill', 'none')
                        .attr('stroke', config.lineStroke)
                        .attr('transform-origin', () => chart.oldY * Math.cos(chart.oldX - Math.PI/2) + ' ' + chart.oldY * Math.sin(chart.oldX - Math.PI/2))
                        .attr('transform', 'scale(0.01)')
                      .merge(links)
                        .transition().duration(config.animateDuration)
                        .attr('transform', 'scale(1)')
                        .attr('d', d3.linkRadial()
                                    .angle((d) => d.x)
                                    .radius((d) => d.y)
                         );
    
                links.exit()
                        .attr('transform-origin', () => chart.targetNode.y * Math.cos(chart.targetNode.x - Math.PI/2) + ' ' + chart.targetNode.y * Math.sin(chart.targetNode.x - Math.PI/2))  //子树逐渐缩小到新位置
                        .transition().duration(config.animateDuration)
                        .attr('transform', 'scale(0.01)')
                        .remove();
    
        }

**最后绑定鼠标交互事件，当点击某个节点隐藏子树时，将其`children`属性设置为`null`，并暂存其子树数据，重新触发布局。当点击某各节点显现子树时，将暂存的子树数据拿出并重新赋值`children`属性，并重新布局，如此达到子树切换的效果。**

/* ----------------------------绑定鼠标交互事件------------------------ */
        chart.addMouseOn = function(){ 
            d3.selectAll('.g')
                .on('click', function(d){ 
                    toggle(d);
                    generateTree(root);
                    chart.renderNode();
                    chart.renderLines();
                    chart.renderText();
                    chart.addMouseOn();
                });
    
            function toggle(d){ 
                chart.first = true;
                if (d.children){ 
                    d._children = d.children;
                    d.children = null;
                }else{ 
                    d.children = d._children;
                    d._children = null;
                }
                chart.oldX = d.x;  //点击位置x坐标
                chart.oldY = d.y;  //点击位置y坐标
                chart.targetNode = d;  //被点击的节点，该节点的x和y坐标随后将被更新
            }
        }

# 大功告成!!! #

--------------------

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![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3pqd19weXRob24_size_16_color_FFFFFF_t_70_pic_center]

[-]: https://blog.csdn.net/zjw_python/article/details/101027698
[Link 1]: https://blog.csdn.net/zjw_python/article/details/98182540
[Link 2]: https://github.com/zjw666/D3_demo/tree/master/src/treeChart/radialTree
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[Link 3]: https://blog.csdn.net/zjw_python/article/details/98492510
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