Ask HN: Need C code for drawing graphic primitives to a framebuffer

2•Surac•3h ago

I have a framebuffer that must be seen as being slow. Also the cpu accessing the fb has no cache whatsoever to accelerate the memory access. I need c code for drawing thick lines with endcaps, thick circles, thick elipsoids and thick beizier curves. I have code to do all this 1 pixel wide, but I need code to draw them with a width without plotting over and over each pixel. I already have Bresenham implementation for lines, circles, ellipsis and beizier

Comments

mfabbri77•3h ago

You need to look at a 2d vector graphics library eg: Skia, Cairo, Agg, NanoVG, Blend2D, OpenVG (and many other, in no particular order).

Surac•2h ago

Thanks. This librarys are so full of features that they literally burry the real drawing part. I had hoped for something more basic. No anti aliasing etc.

mfabbri77•2h ago

You have to look for "stroking": there are several ways to do it, in CPU you usually first perform a piecewise linear approximation of the curve, then offset each segment along the normals, add the caps, get a polygon and draw it.

mathiaspoint•2h ago

You probably want to draw curves and polygons then fill them.

It's possible to imagine drawing extra thick lines by modifying the algorithm but the equivalent changes to a curve would leave gaps. I suppose you could figure out how eg boundary paths for beziers are calculated and transform your algorithm so each step draws to the boundary. It seems like more work for something less general than filling though.

Show HN: Helices Create a New Model of Deterministic Computation [pdf]

Show HN: Free UTM Builder – Instantly generate campaign tracking URLs

Coding is dead: UW computer science program rethinks curriculum for the AI era

Goose Roadmap

I was one of the developers in the METR_Evals study

FDA: Full approval for Moderna's Covid vaccine for children, limited eligibility

Exodus – Painless relocation of Linux binaries and all of their dependencies

Astronomers race to study interstellar interloper

Delta Strips Engines Off New Airbus Jets to Overcome US Shortage

A.I. Can See You in Ways You Can't See Yourself

Kimi K2

How long does a film take to recoup?

Getting a Job in Another Country

The Complete MCP Experience: Full Specification Support in VS Code

Red Lobster's Biz Comeback

Vibe Busters

Turmeric is the culprit in a global lead poisoning mystery

Building Real-Time AI Streaming Services with AWS Lambda and Architect

Making Docs Better for AI and Humans

France launches criminal investigation into Musk's X over algorithm manipulation

China Has Attempted What Might Be First-Ever Orbital Refueling of a Satellite

Police cars could get facial recognition cameras

Linux Patched for Transient Scheduler Attacks "TSA" Impacting AMD CPUs

The zero-day that could've compromised every Cursor and Windsurf user

Microsoft and OpenAI's AGI Fight Is Bigger Than a Contract

Show HN: d2-mcp – compile and render D2 diagrams for multimodal LLMs

Conspiracy theorists unaware their beliefs are on the fringe

Kimi K2: Open Agentic Intelligence

Efficiency of a Sparse Hash Table

Show HN: CNET – a C++/CUDA framework for researching complex valued NN