C++ API (libgw)

GW’s renderer is available as a library, libgw, centred on the Manager::GwPlot class. The v2 API around GwPlot is more stable than v1. The public class is declared in include/libgw/plot_manager.h; include/libgw/libgwplot.hpp aggregates the public headers.

Build the shared library with:

make shared    # produces libgw.so / libgw.dylib

Core concepts

Manager::GwPlot owns window state, loaded files (BAM/CRAM, tracks, variants), active regions, read collections, popup state and command execution context
selectedAlign is the current SAM record used by commands such as mate add, sam, tags and find
Input events are delivered through keyPress, mouseButton, mousePos and scrollGesture, mirroring the GLFW callbacks

Common operations

Manager::GwPlot plot;
plot.init(width, height);                 // create framebuffers
plot.loadGenome("hg38", std::cerr);       // genome tag or fasta path
plot.addBam(bam_path);
plot.addTrack(track_path, true, false, false);
plot.fetchRefSeqs();
plot.processBam();
plot.setScaling();
plot.drawScreen(canvas, sContext, sSurface);  // render a frame to a Skia surface
plot.rasterToPng("out.png");                  // save the current raster

Command-box commands can also be run programmatically through the command parser; sessions can be saved/restored with loadSession.

Remote-viewer session adapter

The optional deps/protocol/viewer/native layer (GwViewer::Session, built via make server-core) wraps GwPlot for the remote viewer protocol: navigation, command execution, input handling, layout/popup state, frame caching and PNG encoding. It exposes standard C++ types only — no Skia, GLFW or server-framework types cross the interface.

The desktop and libgw targets do not compile this adapter; it is an explicit integration choice, not a dependency.

For language bindings:

Python (gwplot): https://github.com/kcleal/gwplot
JavaScript (gwplot-js): https://github.com/APridgeon/gwplot-js