Line Chart Generator

Generate professional line charts for time-series data with minimal effort.

Quick Start

Basic Chart

Generate a simple line chart from data points:

python scripts/generate_chart.py \
  --title "Stock Price Trend" \
  --xlabel "Date" \
  --ylabel "Price (CNY)" \
  --data "2025-12-01:100,2025-12-05:110,2025-12-10:105" \
  -o chart.png

Chart with Annotations

Add annotations to highlight key events:

python scripts/generate_chart.py \
  --title "Revenue Growth" \
  --xlabel "Date" \
  --ylabel "Revenue (M)" \
  --data "2025-01-01:10,2025-02-01:15,2025-03-01:20" \
  --annotations '{"items": [{"date": "2025-02-01", "value": 15, "text": "Q1 Milestone"}]}' \
  -o chart.png

Chart with Reference Lines

Add horizontal reference lines (e.g., target values, baselines):

python scripts/generate_chart.py \
  --title "Performance Metrics" \
  --ylabel "Score" \
  --data "2025-01-01:80,2025-02-01:85,2025-03-01:90" \
  --reference-lines '[{"value": 100, "color": "green", "label": "Target"}]' \
  -o chart.png

Using JSON Data File

For large datasets, use a JSON file:

data.json:

[
  { "date": "2025-12-01", "value": 100 },
  { "date": "2025-12-05", "value": 110 },
  { "date": "2025-12-10", "value": 105 }
]

python scripts/generate_chart.py \
  --title "Price Trend" \
  --ylabel "Price" \
  --data-file data.json \
  -o chart.png

Chart Customization

Dimensions

Adjust chart size:

--width 16 --height 8

Grid and Markers

Disable grid or data point markers:

--no-grid --no-markers

Annotations Format

Annotations as JSON string:

{
  "items": [
    { "date": "2025-12-05", "value": 110, "text": "Peak price" },
    { "date": "2025-12-10", "value": 90, "text": "Dip" }
  ]
}

Reference Lines Format

Reference lines as JSON string:

[
  { "value": 100, "color": "red", "label": "Baseline" },
  { "value": 150, "color": "green", "label": "Target" }
]

Data Format

Data points use format: YYYY-MM-DD:VALUE

• Dates must be in ISO format (YYYY-MM-DD)
• Values must be numeric
• Multiple points separated by commas
• No spaces around the colon

Valid examples:

• 2025-12-01:100
• 2026-01-15:1715
• 2025-03-30:2500.5

Invalid examples:

• 12/01/2025:100 (wrong date format)
• 2025-12-01: $100 (no currency symbols)
• 2025 12 01:100 (wrong separator)

Requirements

• Python 3.x
• matplotlib: Install with pip install matplotlib

Output

Charts are saved as PNG files at 150 DPI with transparent backgrounds suitable for presentations and reports.