antv-g2-chart

name	antv-g2-chart
description	Generate G2 v5 chart code. Use when user asks for G2 charts, bar charts, line charts, pie charts, scatter plots, area charts, or any data visualization with G2 library.

G2 v5 Chart Code Generator

You are an expert in AntV G2 v5 charting library. Generate accurate, runnable code following G2 v5 best practices.

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1. Core Constraints (MUST follow)

1. container is mandatory: new Chart({ container: 'container', ... })
2. Use Spec Mode ONLY: chart.options({ type: 'interval', data, encode: {...} }) (See Forbidden Patterns for V4 chained API)
3. chart.options() can only be called once: Multiple calls will completely overwrite the previous configuration, only the last call takes effect. For multiple mark overlays, use type: 'view' + children array instead of multiple calls to chart.options()
4. encode object: encode: { x, y } (V4's .position('x*y') is forbidden)
5. transform must be array: transform: [{ type: 'stackY' }]
6. labels is plural: Use labels: [{ text: 'field' }] not label: {}
7. coordinate rules:
   • Directly specify coordinate type: coordinate: { type: 'theta' }, coordinate: { type: 'polar' }
   • transpose is a transformation, not a coordinate type, and must be placed in the transform array: coordinate: { transform: [{ type: 'transpose' }] }
   • ❌ Forbidden: coordinate: { type: 'transpose' }
8. Range encoding (Gantt chart, candlestick, etc.): encode: { y: 'start', y1: 'end' }, forbidden: y: ['start', 'end']
9. Style principles: Styles mentioned in the user description (radius, fillOpacity, color, fontSize, etc.) must be fully preserved; do not add decorative styles not mentioned by the user (shadowBlur, shadowColor, shadowOffsetX/Y, etc.)
10. animate rules: Do not add animate configuration when the user does not explicitly request animation (G2 has default animations built-in), only add when the user explicitly describes animation requirements
11. scale.color.palette can only use valid values: Palette is looked up via d3-scale-chromatic, invalid names will throw Unknown palette error. Do not infer or create non-existent names (e.g., 'blueOrange', 'redGreen', 'hot', 'jet', 'coolwarm' are all invalid). Common valid values: sequential color scales 'blues'|'greens'|'reds'|'ylOrRd'|'viridis'|'plasma'|'turbo'; diverging color scales 'rdBu'|'rdYlGn'|'spectral'; when unsure, use range: ['#startColor', '#endColor'] for custom replacement
12. Forbidden to use d3.* in user code: G2 internally uses d3, but the d3 object is not exposed to the user code scope, calling d3.sum() etc. will throw ReferenceError: d3 is not defined. For aggregation, prioritize using G2 built-in options (e.g., sortX's reducer: 'sum'), when custom aggregation is necessary, use native JS: d3.sum(arr, d=>d.v) → arr.reduce((s,d)=>s+d.v,0); d3.max(arr, d=>d.v) → Math.max(...arr.map(d=>d.v))
13. When the user does not specify a color scheme, do not use white or near-white as the shape fill color: style: { fill: '#fff' }, style: { fill: 'white' }, style: { fill: '#ffffff' } etc. will make the shape completely invisible on a white background. When no color scheme is specified, rely on G2's encode.color to automatically assign theme colors, or use colors with clear visual distinction (e.g., '#5B8FF9'). The following are valid exceptions: label text fill: '#fff' (labels within dark backgrounds), separator lines stroke: '#fff' (white separator lines in stacked/pack/treemap)
14. padding only accepts number | 'auto', array form is forbidden: padding: [40, 30, 40, 50] is invalid in G2 v5 (will be ignored or throw an error). For uniform padding, use padding: 40; for directional control, use paddingTop / paddingRight / paddingBottom / paddingLeft individually; default 'auto' automatically reserves space for axes/legends, manual configuration is usually unnecessary. Forbidden to set padding: 0—this will disable automatic calculation, causing axes/legends to be truncated; when adjusting only one direction, set the corresponding direction individually
15. When autoFit: true, do not set width simultaneously: autoFit will completely ignore width, rendering it ineffective when both are present. When autoFit: true, set only height; when fixed width and height are needed, remove autoFit and use width + height instead
16. When the user does not specify a container: container defaults to 'container', do not create via document.createElement('div'), the code must end with chart.render();

1.1 Forbidden Patterns

Forbidden: V4 Syntax, Must use V5 Spec Mode:

// ❌ Forbidden: V4 createView
const view = chart.createView();
view.options({...});

// ❌ Forbidden: V4 Chained API Calls
chart.interval()
  .data([...])
  .encode('x', 'genre')
  .encode('y', 'sold')
  .style({ radius: 4 });

// ❌ Forbidden: V4 Chained encode
chart.line().encode('x', 'date').encode('y', 'value');

// ❌ Forbidden: V4 source
chart.source(data);

// ❌ Forbidden: V4 position
chart.interval().position('genre*sold');

// ✅ Correct: V5 Spec Mode
chart.options({
  type: 'interval',
  data: [...],
  encode: { x: 'genre', y: 'sold' },
  style: { radius: 4 },
});

Reason: V5 uses Spec mode, which has a clear structure and is easy to serialize, dynamically generate, and debug.

Correct V5 Alternative for createView

chart.createView() in V4 was used for "multiple views sharing a container but with different data". In V5, it corresponds to two scenarios:

Scenario A: Multiple marks stacked within the same coordinate system (most common) → Use type: 'view' + children array, children cannot be nested with view or children:

// ✅ Multiple marks stacked (line + point)
chart.options({
  type: 'view',
  data,
  children: [
    { type: 'line',  encode: { x: 'date', y: 'value' } },
    { type: 'point', encode: { x: 'date', y: 'value' } },
  ],
});

Scenario B: Multiple independent coordinate systems side by side or stacked (e.g., population pyramid, butterfly chart) → Use type: 'spaceLayer' + children (each child view has independent data and coordinate system):

// ✅ Population Pyramid: Two independent views stacked, sharing the Y-axis
chart.options({
  type: 'spaceLayer',
  children: [
    {
      type: 'interval',
      data: leftData,                              // Left data (negative values or flipped)
      coordinate: { transform: [{ type: 'transpose' }, { type: 'reflectX' }] },
      encode: { x: 'age', y: 'male' },
      axis: { y: { position: 'right' } },
    },
    {
      type: 'interval',
      data: rightData,                             // Right data
      coordinate: { transform: [{ type: 'transpose' }] },
      encode: { x: 'age', y: 'female' },
      axis: { y: false },
    },
  ],
});

// ✅ Simpler approach: Single view + negative value trick (data can be in one array)
chart.options({
  type: 'interval',
  data: combinedData,                              // Combined data, using negative values to distinguish direction
  coordinate: { transform: [{ type: 'transpose' }] },
  encode: {
    x: 'age',
    y: (d) => d.sex === 'male' ? -d.population : d.population,
    color: 'sex',
  },
  axis: {
    y: { labelFormatter: (d) => Math.abs(d) },     // Display absolute values
  },
});

Selection Principle:

• If both sides have the same data structure but opposite directions → Prioritize negative value trick (single interval, most concise code)
• If both sides require completely independent coordinate systems/scales → Use spaceLayer

1.2 Prohibited Hallucinated Mark Types

The following types are from other charting libraries (such as ECharts, Vega) and do not exist in G2. Using them will result in runtime errors:

❌ Incorrect Usage	✅ Correct Replacement
type: 'ruleX'	type: 'lineX' (vertical reference line)
type: 'ruleY'	type: 'lineY' (horizontal reference line)
type: 'regionX'	type: 'rangeX' (X-axis range highlight)
type: 'regionY'	type: 'rangeY' (Y-axis range highlight)
type: 'venn'	type: 'path' + data.transform: [{ type: 'venn' }]

Complete List of Valid Mark Types in G2 (do not create other types arbitrarily):

• Basic: interval, line, area, point, rect, cell, text, image, path, polygon, shape
• Connections: link, connector, vector
• Reference Lines/Areas: lineX, lineY, rangeX, rangeY; range (rarely used, only when both x/y need to define a 2D rectangle, and the x/y fields of the data must be [start, end] arrays)
• Statistical: box, boxplot, density, heatmap, beeswarm
• Hierarchical/Relational: treemap, pack, partition, tree, sankey, chord, forceGraph
• Special: wordCloud, gauge, liquid
• Requires Extension Package: sunburst (requires @antv/g2-extension-plot, see Sunburst Chart)

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2. Common Mistakes

⚠️ Most Frequent Error: Prohibit Multiple Calls to chart.options()

chart.options() is a full replacement, not a merge. When called multiple times, only the last call takes effect, and all previous configurations are lost. Each chart can only call chart.options() once.

// ❌ Wrong: Multiple calls to chart.options() —— Each call fully replaces the previous one, only the last call takes effect
chart.options({ type: 'interval', data, encode: { x: 'x', y: 'y' } });  // ❌ Overwritten, not rendered
chart.options({ type: 'line',     data, encode: { x: 'x', y: 'y' } });  // ❌ Overwritten, not rendered
chart.options({ type: 'text',     data, encode: { x: 'x', y: 'y', text: 'label' } });  // Only this takes effect

// ✅ Correct: Multiple marks must use type: 'view' + children, resolved in one chart.options() call
chart.options({
  type: 'view',
  data,
  children: [
    { type: 'interval', encode: { x: 'x', y: 'y' } },
    { type: 'line',     encode: { x: 'x', y: 'y' } },
    { type: 'text',     encode: { x: 'x', y: 'y', text: 'label' } },
  ],
});

// ✅ When child marks require different data, specify data separately within children
chart.options({
  type: 'view',
  data: mainData,
  children: [
    { type: 'interval', encode: { x: 'x', y: 'y' } },
    { type: 'text', data: labelData, encode: { x: 'x', text: 'label' } },
  ],
});

Multi-mark combination rules:

• Only use children, prohibit marks, layers, etc.
• children cannot be nested (children cannot contain type: 'view' + children)
• Use spaceLayer/spaceFlex for complex multi-coordinate system combinations

// ❌ Wrong: Using marks/layers (prohibited)
chart.options({ type: 'view', data, marks: [...] });   // ❌
chart.options({ type: 'view', data, layers: [...] });  // ❌

// ❌ Wrong: Nested children (prohibited)
chart.options({ type: 'view', children: [{ type: 'view', children: [...] }] });  // ❌

// ✅ Correct: Use spaceLayer for complex multi-coordinate system combinations
chart.options({
  type: 'spaceLayer',
  children: [
    { type: 'view', children: [...] },
    { type: 'line', encode: { x: 'x', y: 'y' } },
  ],
});

Other Common Errors

// ❌ Wrong: padding in array form (CSS shorthand), not supported in G2 v5, will be ignored
const chart = new Chart({ container: 'container', padding: [40, 30, 40, 50] });  // ❌

// ✅ Correct: Uniform padding for all sides
const chart = new Chart({ container: 'container', padding: 40 });

// ✅ Correct: Padding controlled by direction
const chart = new Chart({ container: 'container', paddingTop: 40, paddingLeft: 60 });

// ❌ Wrong: Missing container
const chart = new Chart({ width: 640, height: 480 });

// ✅ Correct: Container required
const chart = new Chart({ container: 'container', width: 640, height: 480 });

// ❌ Wrong: Transform as object
chart.options({ transform: { type: 'stackY' } });

// ✅ Correct: Transform as array
chart.options({ transform: [{ type: 'stackY' }] });

// ❌ Wrong: Label (singular)
chart.options({ label: { text: 'value' } });

// ✅ Correct: Labels (plural)
chart.options({ labels: [{ text: 'value' }] });

// ❌ Wrong: Unnecessary scale type specification
chart.options({ scale: { x: { type: 'linear' }, y: { type: 'linear' } } });

// ✅ Correct: Let G2 infer scale type automatically
chart.options({ scale: { y: { domain: [0, 100] } } });

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3. Basic Structure

import { Chart } from '@antv/g2';

const chart = new Chart({ container: 'container', width: 640, height: 480 });

chart.options({
  type: 'interval',           // Mark type
  data: [...],                // Data array
  encode: { x: 'field', y: 'field', color: 'field' },
  transform: [],              // Data transforms
  scale: {},                  // Scale config
  coordinate: {},             // Coordinate system
  style: {},                  // Style config
  labels: [],                 // Data labels
  tooltip: {},                // Tooltip config
  axis: {},                   // Axis config
  legend: {},                 // Legend config
});

chart.render();

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4. Core Concepts

Core concepts are the foundation of G2, and understanding them is a prerequisite for using G2 correctly.

4.1 Chart Initialization

Chart is the core class of G2, and all charts start from a Chart instance.

import { Chart } from '@antv/g2';

const chart = new Chart({
  container: 'container',  // Required: DOM container ID or element
  width: 640,              // Optional: width
  height: 480,             // Optional: height
  autoFit: true,           // Optional: auto-fit container size
  padding: 'auto',         // Optional: padding
  theme: 'light',          // Optional: theme
});

Detailed Documentation: Chart Initialization

4.2 encode Channel System

encode maps data fields to visual channels and is a core concept in G2.

Channel	Usage	Example
x	X-axis position	encode: { x: 'month' }
y	Y-axis position	encode: { y: 'value' }
color	Color	encode: { color: 'category' }
size	Size	encode: { size: 'population' }
shape	Shape	encode: { shape: 'type' }

Detailed Documentation: encode Channel System

4.3 View Composition (view + children)

Use the view type in conjunction with the children array to compose multiple marks.

chart.options({
  type: 'view',
  data,
  children: [
    { type: 'line', encode: { x: 'date', y: 'value' } },
    { type: 'point', encode: { x: 'date', y: 'value' } },
  ],
});

Detailed Documentation: View Composition

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5. Concepts / Concept Guide

The concept guide helps in selecting the correct chart type and configuration scheme.

5.1 Chart Selection

Select the appropriate chart type based on data characteristics and visualization goals:

Data Relationship	Recommended Chart	Mark
Comparison	Bar Chart, Column Chart	interval
Trend	Line Chart, Area Chart	line, area
Proportion	Pie Chart, Ring Chart	interval + theta
Distribution	Histogram, Box Plot	rect, boxplot
Correlation	Scatter Plot, Bubble Chart	point
Hierarchy	Treemap, Partition Chart, Sunburst Chart	treemap, partition, sunburst (requires extension package)

Detailed Documentation: Chart Selection Guide

5.2 Visual Channels / Visual Channels

Visual channels are the mapping methods from data to visual attributes:

Channel Type	Suitable Data	Perceptual Accuracy
Position	Continuous/Discrete	Highest
Length	Continuous	High
Color (Hue)	Discrete	Medium
Color (Luminance)	Continuous	Medium
Size	Continuous	Medium-Low
Shape	Discrete	Low

Detailed Documentation: Visual Channels

5.3 Color Theory

Selecting an appropriate color scheme enhances chart readability:

Scenario	Recommended Scheme	Example
Categorical Data	Discrete Palette	category10, category20
Continuous Data	Sequential Palette	Blues, RdYlBu
Positive/Negative Contrast	Diverging Palette	RdYlGn

Detailed Documentation: Color Theory

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6. Marks / Chart Types

Marks are the core visualization elements in G2, determining the visual representation of data. Each Mark is suitable for specific data types and visualization scenarios.

6.1 Bar Chart Series / Interval

Bar charts are used to compare the magnitude of categorical data and are one of the most commonly used chart types. Basic bar charts use the interval mark, stacked bar charts require the addition of the stackY transform, and grouped bar charts use the dodgeX transform.

Type	Mark	Key Configuration
Basic Bar Chart	interval	-
Stacked Bar Chart	interval	transform: [{ type: 'stackY' }]
Grouped Bar Chart	interval	transform: [{ type: 'dodgeX' }]
Percentage Bar Chart	interval	transform: [{ type: 'normalizeY' }]
Horizontal Bar Chart	interval	coordinate: { transform: [{ type: 'transpose' }] }

Detailed Documentation: Basic Bar Chart | Stacked Bar Chart | Grouped Bar Chart | Percentage Bar Chart

6.2 Line Chart Series / Line

Line charts are used to display the trend of data changes over time or ordered categories. They support single lines, multi-line comparisons, and different interpolation methods.

Type	Mark	Key Configuration
Basic Line Chart	line	-
Multi-Series Line	line	encode: { color: 'category' }
Smooth Curve	line	encode: { shape: 'smooth' }
Step Line	line	encode: { shape: 'step' }

Detailed Documentation: Basic Line Chart | Multi-Series Line | LineX/LineY

6.3 Area Chart Series / Area

Area charts build upon line charts by filling the area beneath the line, emphasizing the magnitude of change over time. Stacked area charts are used to show the contribution of each part to the whole.

Type	Mark	Key Configuration
Basic Area Chart	area	-
Stacked Area Chart	area	transform: [{ type: 'stackY' }]

Detailed Documentation: Basic Area Chart | Stacked Area Chart

6.4 Pie Chart/Donut Chart / Arc (Pie/Donut)

Pie charts are used to display the proportional relationship of parts to the whole. They are implemented using the theta coordinate system in conjunction with the interval mark.

Type	Mark	Key Configuration
Pie Chart	interval	coordinate: { type: 'theta' } + stackY
Donut Chart	interval	coordinate: { type: 'theta', innerRadius: 0.6 }

Detailed Documentation: Pie Chart | Donut Chart

6.5 Scatter Plot/Bubble Plot / Point

Scatter plots are used to display the relationship between two numerical variables, while bubble plots use the size of the points to represent a third dimension.

Type	Mark	Key Configuration
Scatter Plot	point	encode: { x, y }
Bubble Plot	point	encode: { x, y, size }

Detailed Documentation: Scatter Plot | Bubble Plot

6.6 Histogram

Histograms are used to display the distribution of continuous numerical data, implemented using the rect mark with the binX transform. Unlike bar charts, histograms have no gaps between bars, representing continuous data.

Type	Mark	Key Configuration
Basic Histogram	rect	transform: [{ type: 'binX', y: 'count' }]
Multi-Distribution Comparison	rect	groupBy grouping

Detailed Documentation: Histogram

6.7 Rose Chart / Radial Bar Chart / Polar Charts

Charts under the polar coordinate system, representing numerical values through radius or arc length, are visually more appealing.

Type	Mark	Key Configuration
Rose Chart	interval	coordinate: { type: 'polar' }
Radial Bar Chart	interval	coordinate: { type: 'radial' }

Detailed Documentation: Rose Chart | Radial Bar Chart

6.8 Distribution

Charts that display data distribution characteristics, suitable for statistical analysis and exploratory data analysis.

Type	Mark	Usage
Boxplot	boxplot	Data distribution statistics
Box (Boxplot)	box	Manually specified boxplot with five-number summary
Density Plot	density	Kernel density estimation curve
Violin Plot	density + boxplot	Density distribution + statistical information
Polygon	polygon	Custom polygon area

Detailed Documentation: Boxplot | Box (Boxplot) | Density Plot | Violin Plot | Polygon

6.9 Relation

Charts that display relationships between data, suitable for network analysis and set relationship visualization.

Type	Mark	Use Case
Sankey Diagram	sankey	Flow/transfer relationships
Chord Diagram	chord	Matrix flow relationships
Venn Diagram	path + venn data transform	Set intersection relationships (venn is a data transform, not a mark type)
Arc Diagram	line + point	Node link relationships

Detailed Documentation: Sankey Diagram | Chord Diagram | Venn Diagram | Arc Diagram

6.10 Project Management Chart / Project

Suitable for project management and progress tracking.

Type	Mark	Usage
Gantt Chart	interval	Task scheduling
Bullet Chart	interval + point	KPI metric display

Detailed Documentation: Gantt Chart | Bullet Chart

6.11 Finance

Professional charts for financial data analysis.

Type	Mark	Usage
K-line Chart	link + interval	Stock four-price data

Detailed Documentation: K-line Chart

6.12 Multivariate Data Chart / Multivariate

Charts for displaying multivariate data relationships.

Type	Mark	Use Case
Parallel Coordinates	line	Multivariate data relationship analysis
Radar Chart	line	Multivariate data comparison

Detailed Documentation: Parallel Coordinates | Radar Chart

6.13 Comparison Chart / Comparison

Suitable for data comparison.

Type	Mark	Usage
Bi-directional Bar Chart	interval	Positive and negative data comparison

Detailed Documentation: Bi-directional Bar Chart

6.14 Basic Marks

Basic marks are the foundational building blocks of G2, which can be used independently or combined to construct complex charts.

Type	Mark	Usage
Rectangle	rect	Rectangular area, basis for histograms/heatmaps
Text	text	Text annotations and labels
Image	image	Image mark, representing data points with images
Path	path	Custom path drawing
Link	link	Line connecting two points
Connector	connector	Connection line between data points
Shape	shape	Custom shape drawing
Vector	vector	Vector/arrow mark, for wind field charts, etc.

Detailed Documentation: rect | text | image | path | link | connector | shape | vector

6.15 Range Mark / Range

The range mark is used to display the interval range of data.

Type	Mark	Usage
Time Period/Interval Highlight (X Direction)	rangeX	X-axis interval, encode: { x: 'start', x1: 'end' }
Numerical Range Highlight (Y Direction)	rangeY	Y-axis interval, encode: { y: 'min', y1: 'max' }
Two-Dimensional Rectangular Area	range	x/y fields are [start,end] arrays, encode: { x:'x', y:'y' }, rarely used

Detailed Documentation: range/rangeY | rangeX

6.16 Distribution & Pack

Type	Mark	Usage
Beeswarm Plot	point + pack	Closely arranged data points to display distribution
Pack Layout	pack	Circular packing for hierarchical data

Detailed Documentation: Beeswarm Plot | Pack Layout

6.17 Hierarchy

Charts for displaying hierarchical data, representing numerical proportions through area or radius.

Type	Mark	Usage
Treemap	treemap	Hierarchical data proportion
Sunburst	sunburst⚠️	Multi-level concentric circle display (requires @antv/g2-extension-plot)
Partition	partition	Hierarchical data partition display
Tree	tree	Tree-like hierarchical structure

Detailed Documentation: Treemap | Sunburst | Partition | Tree

6.18 Other Charts / Others

Type	Mark	Usage
Heatmap	cell	Visualization of two-dimensional matrix data
Density Heatmap	heatmap	Continuous density heatmap
Gauge	gauge	Metric progress display
Word Cloud	wordCloud	Text frequency visualization
Liquid Fill Gauge	liquid	Percentage progress

Detailed Documentation: Heatmap | Density Heatmap | Gauge | Word Cloud | Liquid Fill Gauge

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7. Data / Data Transformation

Data transformation is performed during the data loading stage and is configured in data.transform, affecting all marks that use this data.

7.1 Data Transform Types (Configured in data.transform)

Transform	Type	Purpose	Example Scenario
fold	fold	Wide table to long table	Convert multi-column data to multiple series
filter	filter	Conditional data filtering	Filter invalid data
sort	sort	Sort using a callback function	Custom sorting logic
sortBy	sortBy	Sort by field	Sort by field values
map	map	Data mapping transformation	Add computed fields
join	join	Merge data tables	Associate external data
pick	pick	Select specified fields	Simplify fields
rename	rename	Rename fields	Field renaming
slice	slice	Slice data range	Pagination/slicing
ema	ema	Exponential Moving Average	Time series smoothing
kde	kde	Kernel Density Estimation	Density plot/violin plot
log	log	Print data to console	Debugging
custom	custom	Custom data processing	Complex transformations

7.2 Data Format and Patterns

Type	Purpose
Tabular Data Format	Description of the standard tabular data format accepted by G2
Data Transformation Patterns	Combination usage patterns of Data Transform and Mark Transform

Detailed Documentation: filter | sort | sortBy | fold | slice | ema | kde | log | fetch | Data Transformation Patterns

7.3 Common Mistakes: Incorrect Placement of Data Transform

// ❌ Wrong: fold is a data transform and cannot be placed in mark transform
chart.options({
  type: 'interval',
  data: wideData,
  transform: [{ type: 'fold', fields: ['a', 'b'] }],  // ❌ Wrong!
});

// ✅ Correct: fold placed in data.transform
chart.options({
  type: 'interval',
  data: {
    type: 'inline',
    value: wideData,
    transform: [{ type: 'fold', fields: ['a', 'b'] }],  // ✅ Correct
  },
  transform: [{ type: 'stackY' }],  // mark transform
});

7.4 Combination Example: Wide Table Data + Stacked Chart

// Wide table data: Multiple data columns for each month
const wideData = [
  { year: '2000', 'Type A': 21, 'Type B': 16, 'Type C': 8 },
  { year: '2001', 'Type A': 25, 'Type B': 16, 'Type C': 8 },
  // ...
];

chart.options({
  type: 'interval',
  data: {
    type: 'inline',
    value: wideData,
    transform: [
      // ✅ Data Transform: Wide to Long Table
      { type: 'fold', fields: ['Type A', 'Type B', 'Type C'], key: 'type', value: 'value' },
    ],
  },
  encode: { x: 'year', y: 'value', color: 'type' },
  transform: [
    // ✅ Mark Transform: Stacked
    { type: 'stackY' },
  ],
  coordinate: { type: 'polar' },  // Polar coordinate system
});

---

8. Transforms / Mark Transformations

Mark transformations are executed when binding visual channels and are configured in the transform array of the mark. They are used for data aggregation, anti-overlapping, and more.

Configuration Location: The transform array, which is at the same level as data and encode, not in data.transform.

chart.options({
  type: 'interval',
  data,
  encode: { x: 'category', y: 'value', color: 'type' },
  transform: [  // ✅ Mark Transform: At the same level as data/encode
    { type: 'stackY' },
    { type: 'sortX', by: 'y' },
  ],
});

8.1 Anti-overlap Transformations

Transformation	Type	Purpose
Stack	stackY	Data stacking, used for stacked charts
Dodge	dodgeX	Data grouping, used for dodged charts
Jitter	jitter	Scatter jitter to avoid overlap
Jitter X	jitterX	Jitter in the X direction
Jitter Y	jitterY	Jitter in the Y direction
Pack	pack	Tightly arrange data points

Detailed Documentation: stackY | dodgeX | jitter | jitterX | jitterY | pack

8.2 Aggregation Transforms / Aggregation

Transform	Type	Purpose
General Grouping	group	General grouping aggregation
Group Aggregation	groupX / groupY	Group and aggregate by dimension
Group Color	groupColor	Group aggregation by color
Binning	bin	Two-dimensional binning
X-axis Binning	binX	Binning in the X-axis direction
Sampling	sample	Data sampling

Detailed Documentation: group | groupX | groupY | groupColor | bin | binX | sample

8.3 Sorting Transforms / Sorting

Transform	Type	Purpose
X-axis Sorting	sortX	Sort by X channel
Y-axis Sorting	sortY	Sort by Y channel
Color Sorting	sortColor	Sort by color channel

Detailed Documentation: sortX | sortY | sortColor

8.4 Selection Transforms / Selection

Transform	Type	Purpose
Selection	select	Global data selection
X-axis Selection	selectX	Selection by X grouping
Y-axis Selection	selectY	Selection by Y grouping

Detailed Documentation: select | selectX | selectY

8.5 Other Transforms / Others

Transform	Type	Usage
Normalize	normalizeY	Y-axis normalization
Difference	diffY	Calculate differences
Symmetry	symmetryY	Y-axis symmetry
Flex X	flexX	X-axis flex layout
Stack Enter	stackEnter	Stacked enter animation

Detailed Documentation: normalizeY | diffY | symmetryY | flexX | stackEnter

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9. Interactions

G2 provides a rich set of built-in interactions for data exploration and chart manipulation.

9.1 Selection Interactions

Interaction	Type	Purpose
Element Selection	elementSelect	Click to select data elements
Conditional Selection	elementSelectBy	Batch select elements based on conditions
Brush Selection	brush / brushX / brushY	Rectangular area selection
2D Brush Selection	brushXY	Simultaneous XY brush selection
Axis Brush Selection	brushAxis	Coordinate axis range selection
Legend Filter	legendFilter	Click legend to filter data

Detailed Documentation: elementSelect | elementSelectBy | brush | brushXY | brushAxis | legendFilter

9.2 Highlight Interactions / Highlight

Interaction	Type	Purpose
Element Highlight	elementHighlight	Hover to highlight elements
Conditional Highlight	elementHighlightBy	Batch highlight elements based on conditions
Hover Scale	elementHoverScale	Scale up elements on hover
Legend Highlight	legendHighlight	Hover legend to highlight corresponding elements
Brush Highlight	brushXHighlight / brushYHighlight	Highlight selected area

Detailed Documentation: elementHighlight | elementHighlightBy | elementHoverScale | legendHighlight | brushXHighlight | brushYHighlight | Single-axis Brush Highlight

9.3 Filter Interactions / Filter

Interaction	Type	Purpose
Slider Filter	sliderFilter	Filter data range using a slider
Scrollbar Filter	scrollbarFilter	Filter data using a scrollbar
Brush Filter	brushFilter	Filter data within a selected area
X-axis Brush Filter	brushXFilter	Filter data along the X-axis direction
Y-axis Brush Filter	brushYFilter	Filter data along the Y-axis direction
Adaptive Filter	adaptiveFilter	Adaptively filter data

Detailed Documentation: sliderFilter | scrollbarFilter | brushFilter | brushXFilter | brushYFilter | adaptiveFilter

9.4 Other Interactions / Others

Interaction	Type	Purpose
Tooltip	tooltip	Display data details on hover
PopTip	poptip	Concise pop-up tip
Drilldown	drilldown	Hierarchical data drilldown
Treemap Drilldown	treemapDrilldown	Treemap hierarchical drilldown
Fisheye	fisheye	Fisheye magnifier effect
Slider Wheel	sliderWheel	Mouse wheel control for slider
Element Point Move	elementPointMove	Drag data point to move
Chart Index	chartIndex	Multi-chart linkage index line

Detailed Documentation: tooltip | poptip | drilldown | treemapDrilldown | fisheye | sliderWheel | elementPointMove | chartIndex

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10. Components / 组件

Components are auxiliary elements of charts, such as axes, legends, and tooltips.

10.1 Axis

The axis displays data dimensions and supports rich style configurations.

Detailed Documentation: Axis Configuration | Radar Chart Axis

10.2 Legend

The legend displays data categorization or continuous value mapping, supporting categorical legends and continuous legends (color ramps).

Type	Purpose
Categorical Legend	Color mapping explanation for discrete categorical data
Continuous Legend	Color/size mapping explanation for continuous values (color ramp)

Detailed Documentation: Legend Configuration | Categorical Legend | Continuous Legend

10.3 Tooltip

Tooltip displays data details on hover and supports custom templates and formatting.

Detailed Documentation: Tooltip Configuration

10.4 Other Components / Others

Component	Purpose
Title	Chart title
Label	Data label
Scrollbar	Data scrolling
Slider	Data range selection
Annotation	Data annotation and auxiliary lines

Detailed Documentation: Title | Label | Scrollbar | Slider | Annotation

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11. Scales

Scales map data values to visual channels such as position, color, size, and more.

11.1 ⚠️ Default Behavior (Avoid Over-Specifying type)

G2 automatically infers the scale type based on the data type. Avoid manually specifying type unless necessary:

Data Type	Inferred Scale	Example
Numerical Field	linear	{ value: 100 } → linear
Categorical Field	band	{ category: 'A' } → band
Date Object	time	{ date: new Date() } → time

// ❌ Incorrect: Unnecessary type specification may cause rendering issues
chart.options({
  scale: {
    x: { type: 'linear' },  // ❌ Numerical fields default to linear
    y: { type: 'linear' },  // ❌ No need to specify
  },
});

// ✅ Correct: Let G2 infer automatically, configure domain/range only when needed
chart.options({
  scale: {
    y: { domain: [0, 100] },  // ✅ Configure only necessary properties
    color: { range: ['#1890ff', '#52c41a'] },
  },
});

Special Cases Requiring Manual type Specification:

Scenario	Type	Description
Logarithmic Scale	log	Data spanning multiple orders of magnitude
Power Scale	pow	Non-linear data mapping
Square Root Scale	sqrt	Compression of non-negative data
String Date	time	Date field is a string, not a Date object
Custom Mapping	ordinal	Discrete to discrete mapping
Gradient Color	sequential	Continuous values to color gradient
Threshold Mapping	threshold	Mapping by threshold to colors
Equal Interval Binning	quantize / quantile	Discretization of continuous data

11.2 Scale Types

Scale	Type	Usage
Linear	linear	Continuous numerical mapping (default)
Band	band	Discrete categorical mapping (default)
Point	point	Discrete point position mapping
Time	time	Time data mapping
Log	log	Logarithmic scale
Power/Square Root	pow / sqrt	Power function/square root mapping
Ordinal	ordinal	Discrete to discrete value mapping
Sequential	sequential	Continuous value to color gradient
Quantile/Quantize	quantile / quantize	Continuous data discretization mapping
Threshold	threshold	Segmented mapping by threshold

Detailed Documentation: linear | band | point | time | log | pow/sqrt | ordinal | sequential | quantile/quantize | threshold

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12. Coordinates / 坐标系

The coordinate system defines the mapping method from data to canvas position, and different coordinate systems produce different chart forms.

Coordinate System	Type	Usage
Cartesian	cartesian	Rectangular coordinate system (default)
Polar	polar	Radar chart, rose chart
Theta	theta	Pie chart, donut chart
Radial	radial	Radial coordinate system, gauge chart
Transpose	transpose	X/Y axis swap
Parallel	parallel	Parallel coordinate system
Helix	helix	Helix coordinate system
Fisheye	fisheye	Local magnification effect

Detailed Documentation: cartesian | polar | theta | radial | transpose | parallel | helix | fisheye

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13. Compositions / Composition Views

Composition views are used to create multi-chart layouts, such as facets, multi-view overlays, etc.

Composition	Type	Purpose
Basic View	view	Single view container, combining multiple marks
Facet Rect	facetRect	Split rectangular grid multi-chart by dimension
Facet Circle	facetCircle	Split circular multi-chart by dimension
Repeat Matrix	repeatMatrix	Multi-variable combination matrix chart
Space Layer	spaceLayer	Multi-layer overlay
Space Flex	spaceFlex	Flexible layout
Timing Keyframe	timingKeyframe	Animation sequence
Geo View	geoView	Geographic coordinate system view
Geo Path	geoPath	Geographic path rendering

Detailed Documentation: view | facetRect | facetCircle | repeatMatrix | spaceLayer | spaceFlex | timingKeyframe | geoView | geoPath

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14. Themes / 主题

Themes define the overall visual style of a chart, including colors, fonts, spacing, and more.

Detailed Documentation: Built-in Themes | Custom Themes

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15. Palettes

Palettes define color sequences, used for color mapping of categorical or continuous data.

Detailed Documentation: category10 | category20

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16. Animations

Animations enhance the expressiveness of charts, supporting entrance, update, and exit animation configurations.

⚠️ Important Rule: G2 comes with default animation effects at the underlying level. Do not add animate configurations unless the user explicitly requests animations. Only when the user clearly describes animation requirements (e.g., "fade-in animation", "wave entrance", etc.) should you refer to the documentation and add the corresponding animate configuration.

Detailed Documentation: Animation Introduction | Animation Types | Keyframe Animation

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17. Label Transforms

Label transforms are used to handle issues such as label overlap and overflow, improving label readability.

Transform	Type	Purpose
Overflow Hide	overflowHide	Hide labels that exceed the area
Overlap Hide	overlapHide	Automatically hide overlapping labels
Overlap Dodge Y	overlapDodgeY	Offset overlapping labels in the Y direction
Contrast Reverse	contrastReverse	Automatically reverse label colors to ensure contrast
Exceed Adjust	exceedAdjust	Adjust the position of labels that exceed the canvas boundaries
Overflow Stroke	overflowStroke	Add stroke marks to overflow areas

Detailed Documentation: overflowHide | overlapHide | overlapDodgeY | contrastReverse | exceedAdjust | overflowStroke

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18. Patterns

Patterns are best practices for common scenarios, including migration guides, performance optimization, and responsive adaptation.

18.1 Migration Guide / Migration (v4 → v5)

v4 (Deprecated)	v5 (Correct)
chart.source(data)	chart.options({ data })
.position('x*y')	encode: { x: 'x', y: 'y' }
.color('field')	encode: { color: 'field' }
.adjust('stack')	transform: [{ type: 'stackY' }]
.adjust('dodge')	transform: [{ type: 'dodgeX' }]
label: {}	labels: [{}]

Detailed Documentation: v4 → v5 Migration

18.2 Performance Optimization / Performance

Data pre-aggregation, LTTB downsampling, Canvas renderer confirmation, high-frequency real-time data throttling updates.

Scenario	Data Volume	Recommended Solution
Line Chart	< 1,000 points	Direct rendering
Line Chart	1,000 ~ 10,000 points	Downsample to within 500 points
Line Chart	> 10,000 points	Backend aggregation + time range filtering
Scatter Plot	< 5,000 points	Direct rendering
Scatter Plot	5,000 ~ 50,000 points	Canvas rendering + downsampling

Detailed Documentation: Performance Optimization

18.3 Responsive

autoFit adaptive, ResizeObserver dynamic adjustment, mobile font/margin adaptation.

Detailed Documentation: Responsive Adaptation

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