LIBGVC(3)

🌸 LIBGVC(3) — the Graphviz context library 💖

ok so bestie, this is the libgvc manual page from section 3 of the Library Functions Manual, and honestly? it's the moment. this is the library that gives your app a whole ✨context✨ for messing with graphs and rendering them. let's get into it 🫶

---

✨ NAME ✨

libgvc — the Graphviz context library 🎀

---

💅 SYNOPSIS 💅

first things first, you gotta include it:

#include <graphviz/gvc.h>

then all the little functions, bestie, in order, exactly as they come:

/* set up a graphviz context */
extern GVC_t *gvNEWcontext(const lt_symlist_t *builtins, int demand_loading);

/*  set up a graphviz context ‐ alternative */
/*     (wraps the above two functions using info built into libgvc) */
extern GVC_t *gvContext(void);

/* parse command line args ‐ minimally argv[0] sets layout engine */
extern int gvParseArgs(GVC_t *gvc, int argc, char **argv);
extern graph_t *gvNextInputGraph(GVC_t *gvc);

/* Compute a layout using a specified engine */
extern int gvLayout(GVC_t *gvc, graph_t *g, char *engine);

/* Compute a layout using layout engine from command line args */
extern int gvLayoutJobs(GVC_t *gvc, graph_t *g);

/* Check if a layout has been done */
extern bool gvLayoutDone(graph_t *g);

/* Render layout into string attributes of the graph */
extern void attach_attrs(graph_t *g);

/* Parse an html string */
extern char *agstrdup_html(char *s);
extern int aghtmlstr(char *s);

/* Render layout in a specified format to an open FILE */
extern int gvRender(GVC_t *gvc, graph_t *g, char *format, FILE *out);

/* Render layout in a specified format to an open FILE */
extern int gvRenderFilename(GVC_t *gvc, graph_t *g, char *format, char *filename);

/* Render layout according to -T and -o options found by gvParseArgs */
extern int gvRenderJobs(GVC_t *gvc, graph_t *g);

/* Clean up layout data structures ‐ layouts are not nestable (yet) */
extern int gvFreeLayout(GVC_t *gvc, graph_t *g);

/* Clean up graphviz context */
extern int gvFreeContext(GVC_t *gvc);

/* Inquire about available plugins */
/* See comment in gvc.h            */
extern char** gvPluginList(GVC_t *gvc, char* kind, int* cnt, char*);

ngl, that's a lot of externs but every single one of them is iconic in its own way 💖

---

🌈 DESCRIPTION 🌈

ok so here's the tea: libgvc hands your app a whole context so it can manipulate graphs and render them. it's giving main character energy for graph tooling. it brings:

• command line parsing 👑
• common rendering code ✨
• and a whole plugin mechanism for renderers 🧚

literally everything you need to go from "i have a graph" to "i have a rendered graph", no cap.

---

🦋 SEE ALSO 🦋

go read these too, bestie, they're all in the group chat:

• dot(1)
• neato(1)
• cdt(3)
• cgraph(3)

---

💜 AUTHOR 💜

John Ellson (ellson@research.att.com), AT&T — we stan 🫶

---

and that's the whole page, periodt. this was the LIBGVC(3) page from the Library Functions Manual, and yes the footer said LIBGVC(3) too because consistency is a vibe 💅 mwah, go render something cute 🎀💖✨