# Custom styling and export

`vennDiagramLab` separates analysis from rendering. Once you have a `RegionResult`, you can render it with custom names, custom colors, post-process the SVG, embed it in a ggplot2 chain via `geom_venn()`, or export to PNG / PDF.

    library(vennDiagramLab)
    result <- analyze(load_sample("dataset_real_cancer_drivers_4"))

## Custom names

Pass a per-letter mapping (`A`-`I`) to override the dataset’s set names:

    svg <- render_venn_svg(
        result,
        set_names = c(A = "Vogelstein\n(2013)",
                       B = "COSMIC CGC",
                       C = "OncoKB",
                       D = "IntOGen"),
        title = "Pan-source cancer driver agreement"
    )
    substr(svg, 1, 60)

## Custom colors

Pass a per-letter hex map. Each letter’s color is applied to the matching shape AND the legend bullet (and, where present, the Euler extra shape).

    svg <- render_venn_svg(
        result,
        colors = c(A = "#E69F00", B = "#56B4E9", C = "#009E73", D = "#CC79A7")
    )
    nchar(svg)

## Hide the count labels

    svg_clean <- render_venn_svg(result, show_counts = FALSE)
    nchar(svg_clean)

(`show_names = FALSE` does the analogous thing for set names.)

## Post-render SVG manipulation with xml2

The returned SVG is a plain string; parse it with `xml2` to make targeted edits (e.g. set the page background or add a watermark):

    svg <- render_venn_svg(result)
    doc <- xml2::read_xml(svg)
    xml2::xml_attr(doc, "viewBox")

## Embed in a ggplot2 chain

`geom_venn()` returns a list of layers that draws the venn on a unit-square coordinate system, ready to compose with titles, themes, and other annotations.

    library(ggplot2)
    ggplot() +
        geom_venn(data = result) +
        theme_void() +
        labs(title = "4 cancer-driver sources",
              subtitle = "Vogelstein, COSMIC CGC, OncoKB, IntOGen") +
        theme(plot.title = element_text(size = 14, face = "bold"),
              plot.subtitle = element_text(size = 10, colour = "grey40"))

## Multi-format export

`render_venn_svg()` returns a string. Convert it to PNG or PDF via the `rsvg` package (already a hard import of `vennDiagramLab`):

    svg <- render_venn_svg(result)
    png_path <- tempfile(fileext = ".png")
    rsvg::rsvg_png(charToRaw(svg), png_path, width = 1200)
    file.size(png_path)

    pdf_path <- tempfile(fileext = ".pdf")
    rsvg::rsvg_pdf(charToRaw(svg), pdf_path)
    file.size(pdf_path)

For a multi-page composite report (venn + upset + statistics + network + about), use `to_pdf_report()` — see `vignette("v07_pdf_reports")`.

## What’s next

- `vignette("v01_quickstart")` — basic usage.
- `vignette("v04_upset_vs_venn_vs_network")` — alternative visualizations.
- `vignette("v07_pdf_reports")` — composite multi-page PDF reports.