Introduction

The Assignment2 package provides a function, plot_sankey_diagram(), for creating Excel‑style Sankey diagrams using ggplot2.
This vignette demonstrates how to recreate the provided Excel Sankey chart visualizing stroke risk factors over time.

Basic Usage

The package includes an example dataset, stroke_data, which matches the structure of the Excel file.

data("stroke_data")

Basic Sankey diagram with no gaps

plot_sankey_diagram(stroke_data)

Adding Vertical and Horizontal Gaps

You can toggle gaps by setting vertical_gap or horizontal_gap to TRUE.

Horizontal White Space

plot_sankey_diagram(stroke_data, vertical_gap = FALSE, horizontal_gap = TRUE)

Vertical White Space

plot_sankey_diagram(stroke_data, vertical_gap = TRUE, horizontal_gap = FALSE)

Both Horizontal and Vertical White Space

plot_sankey_diagram(stroke_data, vertical_gap = TRUE, horizontal_gap = TRUE)

Adjusting Minimum Ribbon Size

For very small proportions, set a minimum ribbon size so that labels are easier to read.
(Default minimum ribbon size is set to 0.06.)

plot_sankey_diagram(stroke_data, min_ribbon_size = 0.06)

Conclusion

This vignette demonstrates how the plot_sankey_diagram() function replicates the Excel Sankey chart style in R.
You can customize:

- **Colors** (by editing the function’s color scale)  
- **White space** (with `vertical_gap` and `horizontal_gap`)  
- **Ribbon visibility** (with `min_ribbon_size`)  

For further styling, you can apply additional ggplot2 themes or save your plots with ggsave().