Pure Go 2D Graphics Library with GPU Acceleration: Introducing gogpu/gg

Last updated: 2026-02-12

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When I discovered that fogleman/gg — the beloved 2D graphics library for Go — hadn't been updated since 2019, I knew the Go community needed a successor. Today, gogpu/gg has grown to v0.27.1 — a modern, GPU-accelerated 2D graphics library, now part of a 380K+ line Pure Go graphics ecosystem.

The Journey

It started with a Reddit discussion about the state of graphics in Go. The community's frustration was clear: Go deserves better graphics support.

So we built it.

What is gogpu/gg?

gogpu/gg is a Pure Go 2D graphics library for:

• Server-side rendering (charts, reports, image generation)
• Desktop applications (via gogpu framework)
• Professional graphics (PDF export, 29 blend modes, premultiplied alpha)

Key Features

Quick Start

go get github.com/gogpu/gg@latest

package main

import (
    "github.com/gogpu/gg"
    "github.com/gogpu/gg/text"
)

func main() {
    // dc = "drawing context" — the convention from fogleman/gg
    dc := gg.NewContext(512, 512)
    dc.ClearWithColor(gg.White)

    // Draw a filled circle
    dc.SetHexColor("#3498db")
    dc.DrawCircle(256, 256, 100)
    dc.Fill()

    // Stroke a rounded rectangle
    dc.SetHexColor("#e74c3c")
    dc.SetLineWidth(3)
    dc.DrawRoundedRectangle(156, 156, 200, 200, 20)
    dc.Stroke()

    // Load font and draw text
    source, _ := text.NewFontSourceFromFile("arial.ttf")
    defer source.Close()

    dc.SetFont(source.Face(32))
    dc.SetRGB(0, 0, 0)
    dc.DrawString("Hello, GoGPU!", 180, 270)

    dc.SavePNG("output.png")
}

Fluent PathBuilder

// Build complex paths with method chaining
path := gg.BuildPath().
    Circle(100, 100, 50).
    Star(250, 100, 40, 20, 5).
    RoundRect(50, 170, 100, 80, 10).
    Build()

GPU Acceleration (opt-in)

import _ "github.com/gogpu/gg/gpu" // opt-in GPU acceleration

dc := gg.NewContext(800, 600)
dc.DrawCircle(400, 300, 100)
dc.Fill() // GPU renders via SDF if shape detected, CPU fallback otherwise

The SDF accelerator auto-detects circles, ellipses, rectangles, and rounded rectangles from path data. Everything else falls back to the CPU rasterizer — transparently, with ~17ns overhead when no GPU is registered.

Architecture

CPU Core + GPU Accelerator

Based on analysis of 8 enterprise 2D engines (Skia, Cairo, Vello, Blend2D, tiny-skia, piet, Qt RHI, Pathfinder), we follow the same fundamental principle:

CPU rasterization is the core. GPU is an optional accelerator.

gg.Fill() / gg.Stroke()
    │
    ├── GPUAccelerator (if registered via import _ "gg/gpu")
    │      ├── SDF: circles, rects, rrects (hardware-accelerated)
    │      └── Stencil-Then-Cover: general paths (coming soon)
    │
    └── SoftwareRenderer → internal/raster/ (always available)
            ├── Vello-inspired tile rasterizer
            ├── Analytic anti-aliasing
            └── Parallel tile processing

Vello-Inspired Rasterizer

The CPU rasterizer uses the Sparse Strips algorithm, inspired by vello:

• Tile-based processing (16x16 pixel tiles)
• Backdrop computation for winding
• Analytic anti-aliasing coverage
• Parallel tile rendering across CPU cores

Three-Tier GPU Rendering (Roadmap)

The GoGPU Ecosystem

gogpu/gg is part of a Pure Go GPU Computing Ecosystem:

Total: 380K+ lines of Pure Go — no CGO, no Rust, no C.

wgpu Backends

The Pure Go WebGPU implementation supports multiple backends:

Version Highlights

What's Next?

• Stencil-Then-Cover — GPU rendering for all path types (concave, holes, beziers)
• SDF Render Pipeline — Port SDF from compute to render pipeline (avoiding shader compiler limitations)
• Convex Fast Path — Single draw call for convex polygons
• gogpu/ui — Signals-based GUI toolkit (54K LOC, already building)

Acknowledgments

Special thanks to:

• @fogleman for the original gg that inspired this project
• The vello team for Sparse Strips research and Euler spiral flattening
• @raphlinus for confirming our vello implementation is correct
• @amortaza, @ppoage, @Nickrocky for real-world testing
• The Go community on r/golang

Links

• GitHub: https://github.com/gogpu/gg
• GoGPU Organization: https://github.com/gogpu
• Discussion: Join the conversation
• Latest Release: gogpu/gg v0.27.1

Star the repo if you find it useful! Contributions welcome.

go get github.com/gogpu/gg@latest