Vello: GPU-Accelerated 2D Vector Graphics for Python

Vello is a high-performance, GPU compute-centric 2D vector graphics engine for Python, powered by Linebender's Vello and wgpu.

Unlike traditional CPU renderers (like Cairo or CPU Skia) or traditional GPU renderers that rely on tessellation, Vello utilizes modern GPU Compute Shaders to perform sorting, path clipping, and antialiased rasterization in parallel on your graphics card.

✨ Features

• ⚡ Pure GPU Compute Acceleration: Path flattening, clipping, and rasterization run completely on GPU Compute Shaders.
• 🎨 Pythonic Canvas API: An intuitive, HTML5 Canvas-like API designed specifically for Python developers.
• 🚀 Zero-Copy NumPy Integration: Stream rendered frames directly into NumPy (H, W, 4) uint8 arrays without copying memory.
• 🌈 Rich Shading & Gradients: Full support for Solid Colors, Linear Gradients, Radial Gradients, and Image Brushes.
• 📐 Vector Shapes & SVG Paths: Native support for Rectangles, Rounded Rectangles, Circles, Ellipses, Lines, Bézier Curves, and complete SVG path d="..." strings.
• 🔤 GPU Vector Typography: High-quality TrueType/OpenType font rendering with exact subpixel glyph positioning.
• 🎭 Compositing & Blend Modes: Full W3C blend modes (Multiply, Screen, Overlay, etc.) and compositing operations.
• 💡 Gaussian Drop Shadows: Accelerated blurred rounded rectangles for realistic UI drop shadows.
• 🧵 Non-blocking & Thread-Safe: Releases the Python GIL during GPU execution for multi-threaded performance.

📦 Installation

pip install vello

🚀 Quickstart

1. Basic Drawing & PNG Export

import vello

# Create canvas with background color
canvas = vello.Canvas(800, 600, background="white")

# Fill and stroke shapes with CSS colors, hex, or RGB tuples
canvas.fill_circle(cx=400, cy=300, radius=120, fill="royalblue")
canvas.stroke_circle(cx=400, cy=300, radius=120, stroke="crimson", stroke_width=6.0)

# Draw rounded rectangle with GPU drop shadow
canvas.draw_shadow(x=50, y=50, width=200, height=100, radius=16, blur=20, color="#00000044")
canvas.fill_rounded_rect(x=50, y=50, width=200, height=100, radius=16, fill="#2ecc71")

# Draw an SVG path
canvas.fill_path("M 500 100 L 550 200 L 450 200 Z", fill="gold")

# Save directly to image
canvas.save("output.png")

2. High-Performance NumPy & Video / Game Pipelines

import vello

canvas = vello.Canvas(1920, 1080, background="black")

# Draw vector elements
canvas.fill_circle(960, 540, 200, fill="coral")

# Get a NumPy array with zero-copy buffer mapping (shape: 1080, 1920, 4)
frame = canvas.to_numpy()
print(frame.shape, frame.dtype)  # (1080, 1920, 4) uint8

3. Linear & Radial Gradients

import vello

canvas = vello.Canvas(400, 400, background="black")

# Linear gradient
gradient = vello.LinearGradient(
    start=(0, 0),
    end=(400, 400),
    stops=[
        vello.ColorStop(0.0, vello.Color.from_name("red")),
        vello.ColorStop(0.5, vello.Color.from_name("yellow")),
        vello.ColorStop(1.0, vello.Color.from_name("blue")),
    ]
)
canvas.fill_rect(0, 0, 400, 400, fill=gradient)
canvas.save("gradient.png")

4. Transformations & Layer Blending

import vello

canvas = vello.Canvas(500, 500, background="white")

# Context manager for local coordinate transforms
with canvas.transform(translate=(250, 250), rotate_deg=45):
    canvas.fill_rect(-50, -50, 100, 100, fill="teal")

# Blending and opacity layers
with canvas.layer(alpha=0.8, blend_mode="multiply"):
    canvas.fill_circle(200, 200, 80, fill="cyan")
    canvas.fill_circle(260, 200, 80, fill="magenta")

canvas.save("layers.png")

5. Vector Typography

import vello

canvas = vello.Canvas(600, 200, background="white")

# Load any TrueType or OpenType font
font = vello.Font.from_file("C:/Windows/Fonts/arial.ttf")

# Measure text bounds
width, height = font.measure_text("Vello on GPU", size=36.0)

# Draw vector text
canvas.draw_text("Vello on GPU", x=50, y=100, font=font, size=36.0, color="royalblue")
canvas.save("text.png")

📊 Performance

Vello parallelizes vector rendering on GPU compute shaders:

• Instant scene builds: Adding thousands of vector commands takes just a few milliseconds.
• Fast GPU rendering: 1080p full frame renders take ~5-10 ms on standard GPUs (~120-200 FPS).
• GIL-free execution: Multi-threaded Python applications run concurrently without blocking.

📜 License

Licensed under either of:

• Apache License, Version 2.0 (LICENSE-APACHE)
• MIT license (LICENSE-MIT)

at your option.