renderer

graphic中tooltip的TooltipGuide类提供了renderer方法，接收三个参数Size类型，Offset类型，Map<int, Tuple>类型。可查到的文档是真的少，所以只能在源码中扒拉例子，做符合需求的修改。

官方github示例

官方示例

这个例子感觉像是tooltip和提供的那些属性的源码实现，然后改变了背景颜色等，但如果实现想echarts那样对每条线的数据前增加颜色块区分，还是要自己摸索。先看一下这个例子都做了什么吧

List<MarkElement> simpleTooltip(Size size,Offset anchor,Map<int, Tuple> selectedTuples,) {// 返回的元素列表List<MarkElement> elements;// 生成tooltip内容String textContent = '';// 选中的数据 ({date: xxx, name: 线条1, points: xxx}, {date: xx, name: 线条2, points: xx}...)final selectedTupleList = selectedTuples.values;// 选中的数据的字段名列表// 单条线：[date, points]// 多条线：会通过name区分不同线的数值[date, name, points]final fields = selectedTupleList.first.keys.toList();// 如果只有一条线if (selectedTuples.length == 1) {// 取出选中的数据final original = selectedTupleList.single;// 取出第一个字段的值var field = fields.first;// 将第一个字段的值放入到tooltip的第一行/*** 此时的数据结构是：* date: 2023-11-24*/textContent += '$field: ${original[field]}';// 遍历字段名列表for (var i = 1; i < fields.length; i++) {// 取出第i个字段field = fields[i];// 将第i个字段的值放入到tooltip的第二行/*** 遍历后的数据结构是：* date: 2023-11-24* points: 123*/textContent += '\n$field: ${original[field]}';}} else {// 如果有多条线// 遍历选中的数据（几条线几条数据），将每个数据的第二个字段和第三个字段的值放入到tooltip的第二行和第三行for (var original in selectedTupleList) {// 取出第一个字段final domainField = fields.first;// 取出最后一个字段final measureField = fields.last;/*** 遍历结束后的数据结构是：* 2023-11-24：线条1* 2023-11-24：线条2* ....*/textContent += '\n${original[domainField]}: ${original[measureField]}';}}// 提出一些变量const textStyle = TextStyle(fontSize: 12, color: Colors.white);const padding = EdgeInsets.all(5);const align = Alignment.topRight;const offset = Offset(5, -5);const elevation = 1.0;const backgroundColor = Colors.black;final painter = TextPainter(text: TextSpan(text: textContent, style: textStyle),textDirection: TextDirection.ltr,);painter.layout();// 计算tooltip的宽高final width = padding.left + painter.width + padding.right;final height = padding.top + painter.height + padding.bottom;// 调整tooltip弹框（包含内容）的位置final paintPoint = getBlockPaintPoint(anchor + offset,width,height,align,);// 调整tooltip弹框（不包含内容）的位置final window = Rect.fromLTWH(paintPoint.dx,paintPoint.dy,width,height,);// 计算tooltip文本的位置var textPaintPoint = paintPoint + padding.topLeft;elements = <MarkElement>[RectElement(rect: window,style: PaintStyle(fillColor: backgroundColor, elevation: elevation)),LabelElement(text: textContent,anchor: textPaintPoint,style:LabelStyle(textStyle: textStyle, align: Alignment.bottomRight)),];return elements;}

效果

根据需求调整

改动后代码

List<MarkElement> simpleTooltip(Size size,Offset anchor,Map<int, Tuple> selectedTuples,) {// 返回的元素列表List<MarkElement> elements;// 标识元素列表List<MarkElement> tagElements = [];// 生成tooltip内容String textContent = '';// 选中的数据 ({date: xxx, name: 线条1, points: xxx}, {date: xx, name: 线条2, points: xx}...)final selectedTupleList = selectedTuples.values;// 选中的数据的字段名列表 [date, name, points]final fields = selectedTupleList.first.keys.toList();// 选中的数据的第一个数据的第一个字段的值，放入到tooltip的第一行/*** 目前的数据结构是：* 2023-11-24*/textContent = '${selectedTupleList.first[fields.first]}';// 遍历选中的数据（几条线几条数据），将每个数据的第二个字段和第三个字段的值放入到tooltip的第二行和第三行for (var original in selectedTupleList) {final domainField = fields[1];final measureField = fields.last;/*** 遍历结束后的数据结构是：* 2023-11-24* 线条1: 123* 线条2: 456* ....*/textContent += '\n  ${original[domainField]}: ${original[measureField]}';}// 提出一些变量const textStyle = TextStyle(fontSize: 12, color: Colors.black, height: 2);const padding = EdgeInsets.all(5);const align = Alignment.topRight;const offset = Offset(5, -5);const elevation = 1.0;const backgroundColor = Colors.white;final painter = TextPainter(text: TextSpan(text: textContent, style: textStyle),textDirection: ui.TextDirection.ltr,);painter.layout();// tooltip的宽高final width = padding.left + painter.width + padding.right;final height = padding.top + painter.height + padding.bottom;// tooltip的位置// 大概根据中间的数据判断算了下位置,避免一直在左或右,边界超出屏幕final move = anchor < const Offset(250, 90)? anchor + offset - const Offset(-10, -40): anchor + Offset(-width - 20, 40);final paintPoint = getBlockPaintPoint(move,width,height,align,);final window = Rect.fromLTWH(paintPoint.dx - 10, //横向位置paintPoint.dy,width + 20,height,);var textPaintPoint = paintPoint + padding.topLeft;// 生成tooltip线条前的标识元素for (int i = 0; i < selectedTupleList.length; i++) {tagElements.add(LabelElement(text: '●',anchor: textPaintPoint + padding.topLeft + Offset(-15, 26 + i * 23),style: LabelStyle(textStyle: TextStyle(color: Defaults.colors10[i],fontWeight: FontWeight.w900,fontSize: 12),align: Alignment.bottomRight)),);}elements = <MarkElement>[RectElement(rect: window,style: PaintStyle(fillColor: backgroundColor, elevation: elevation)),...tagElements,LabelElement(text: textContent,anchor: textPaintPoint,style:LabelStyle(textStyle: textStyle, align: Alignment.bottomRight)),];return elements;}

效果

整体代码

// linePage.dart
import 'package:flutter/gestures.dart';
import 'package:flutter/material.dart';
import 'package:graphic/graphic.dart';
import 'dart:ui' as ui;
import './components/static/data.dart';class linePage extends StatelessWidget {linePage({super.key});final GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();List<MarkElement> simpleTooltip(Size size,Offset anchor,Map<int, Tuple> selectedTuples,) {// 返回的元素列表List<MarkElement> elements;// 标识元素列表List<MarkElement> tagElements = [];// 生成tooltip内容String textContent = '';// 选中的数据 ({date: xxx, name: 线条1, points: xxx}, {date: xx, name: 线条2, points: xx}...)final selectedTupleList = selectedTuples.values;// 选中的数据的字段名列表 [date, name, points]final fields = selectedTupleList.first.keys.toList();// 选中的数据的第一个数据的第一个字段的值，放入到tooltip的第一行/*** 目前的数据结构是：* 2023-11-24*/textContent = '${selectedTupleList.first[fields.first]}';// 遍历选中的数据（几条线几条数据），将每个数据的第二个字段和第三个字段的值放入到tooltip的第二行和第三行for (var original in selectedTupleList) {final domainField = fields[1];final measureField = fields.last;/*** 遍历结束后的数据结构是：* 2023-11-24* 线条1: 123* 线条2: 456* ....*/textContent += '\n  ${original[domainField]}: ${original[measureField]}';}// 提出一些变量const textStyle = TextStyle(fontSize: 12, color: Colors.black, height: 2);const padding = EdgeInsets.all(5);const align = Alignment.topRight;const offset = Offset(5, -5);const elevation = 1.0;const backgroundColor = Colors.white;final painter = TextPainter(text: TextSpan(text: textContent, style: textStyle),textDirection: ui.TextDirection.ltr,);painter.layout();// tooltip的宽高final width = padding.left + painter.width + padding.right;final height = padding.top + painter.height + padding.bottom;// tooltip的位置// 大概根据中间的数据判断算了下位置,避免一直在左或右,边界超出屏幕final move = anchor < const Offset(250, 90)? anchor + offset - const Offset(-10, -40): anchor + Offset(-width - 20, 40);final paintPoint = getBlockPaintPoint(move,width,height,align,);final window = Rect.fromLTWH(paintPoint.dx - 10, //横向位置paintPoint.dy,width + 20,height,);var textPaintPoint = paintPoint + padding.topLeft;// 生成tooltip线条前的标识元素for (int i = 0; i < selectedTupleList.length; i++) {tagElements.add(LabelElement(text: '●',anchor: textPaintPoint + padding.topLeft + Offset(-15, 26 + i * 23),style: LabelStyle(textStyle: TextStyle(color: Defaults.colors10[i],fontWeight: FontWeight.w900,fontSize: 12),align: Alignment.bottomRight)),);}elements = <MarkElement>[RectElement(rect: window,style: PaintStyle(fillColor: backgroundColor, elevation: elevation)),...tagElements,LabelElement(text: textContent,anchor: textPaintPoint,style:LabelStyle(textStyle: textStyle, align: Alignment.bottomRight)),];return elements;}@overrideWidget build(BuildContext context) {return SingleChildScrollView(child: Center(child: Column(children: <Widget>[Container(padding: const EdgeInsets.fromLTRB(20, 40, 20, 5),child: const Text('Smooth Line and Area chart',style: TextStyle(fontSize: 20),),),Container(margin: const EdgeInsets.only(top: 10),width: 350,height: 300,child: Chart(// 数据源data: invalidData,// 变量配置variables: {'date': Variable(accessor: (Map map) => map['date'] as String,scale: OrdinalScale(tickCount: 5, // x轴刻度数量),),'name': Variable(accessor: (Map map) => map['name'] as String,),'points': Variable(accessor: (Map map) => (map['points'] ?? double.nan) as num,),},marks: [// 线条LineMark(// 如果单线条加name则必须有position属性配置，否则是一条直线position:Varset('date') * Varset('points') / Varset('name'),shape: ShapeEncode(value: BasicLineShape(smooth: true),),// 粗细size: SizeEncode(value: 1.5),),// 线条与X轴之间区域填充AreaMark(// 如果单线条加name则必须有position属性配置，否则不显示position:Varset('date') * Varset('points') / Varset('name'),shape: ShapeEncode(value:BasicAreaShape(smooth: true), // smooth: true 使线条变得平滑),color: ColorEncode(value: Colors.pink.withAlpha(80),),),],// 坐标轴配置axes: [Defaults.horizontalAxis,Defaults.verticalAxis,],selections: {'touchMove': PointSelection(on: {GestureType.scaleUpdate,GestureType.tapDown,GestureType.hover,GestureType.longPressMoveUpdate},dim: Dim.x,)},// 触摸弹框提示tooltip: TooltipGuide(// 跟随鼠标位置// followPointer: [false, true],// align: Alignment.topLeft, // 弹框对于点击位置的对齐方式// offset: const Offset(-20, -20), // 偏移量// 使用自定义需要注释上面的一些配置renderer: simpleTooltip,),// 十字准线crosshair: CrosshairGuide(followPointer: [false, true]),),),Container(padding: const EdgeInsets.fromLTRB(20, 40, 20, 5),child: const Text('Group interactions',style: TextStyle(fontSize: 20),),),Container(margin: const EdgeInsets.only(top: 10),width: 350,height: 300,child: Chart(data: invalidData1,variables