SVGs

PixiJS supports SVG rendering, letting you integrate scalable vector graphics into your projects. This guide covers different ways to use SVGs, including real-time rendering, performance trade-offs, and known limitations.

Why use SVGs?

SVGs have several advantages over raster images like PNGs:

• Smaller file sizes - SVGs can be much smaller than PNGs, especially for large but simple shapes. A high-resolution PNG may be several megabytes while an equivalent SVG could be a few kilobytes.
• Scalability - SVGs scale without losing quality, making them ideal for responsive applications and UI elements.
• Editable after rendering - Unlike textures, SVGs rendered via Graphics can be modified dynamically (e.g., changing stroke colors, modifying shapes).
• Efficient for simple graphics - If the graphic consists of basic shapes and paths, SVGs can be rendered efficiently as vector graphics.

However, SVGs can also be computationally expensive to parse, particularly for intricate illustrations with many paths or effects.

Ways to render SVGs in PixiJS

PixiJS offers two primary ways to render SVGs:

1. As a texture - Converts the SVG into a texture for rendering as a sprite.
2. As a Graphics object - Parses the SVG and renders it as vector geometry.

Each method has its own trade-offs, covered below.

1. Rendering SVGs as textures

SVGs can be loaded as textures and used within Sprites. This method is efficient but does not retain the scalability of vector graphics.

Example

const svgTexture = await Assets.load('tiger.svg');
const mySprite = new Sprite(svgTexture);

@stackblitz(sprite_svg)

Scaling textures

You can specify a resolution when loading an SVG as a texture to control its size. This increases memory usage but produces higher fidelity.

const svgTexture = await Assets.load({
  src: 'path/to.svg',
  data: {
    resolution: 4,
  }
});
const mySprite = new Sprite(svgTexture);

@stackblitz(sprite_svg_custom-data)

Pros and cons

Pros:

• Fast to render (drawn as a single quad, not geometry)
• Good for static images and complex SVGs with fixed dimensions
• Supports resolution scaling for higher fidelity

Cons:

• Scaling causes pixelation (it's a rasterized image)
• Cannot modify shapes dynamically after rasterization
• Texture size limit of 4096x4096 pixels; for larger SVGs, use the Graphics method

When to use

• Background images
• Decorative elements
• Performance-critical applications where scaling isn't needed
• Complex SVGs with fixed dimensions

2. Rendering SVGs as Graphics

PixiJS can render SVGs as scalable vector graphics using the Graphics class.

Example

const graphics = new Graphics().svg('<svg width="100" height="100"><rect width="100" height="100" fill="red"/></svg>');

@stackblitz(graphics_svg_string-parsing)

If you want to use the same SVG multiple times, use GraphicsContext to share the parsed SVG data across multiple graphics objects. This parses it once and reuses the result.

const context = new GraphicsContext().svg(
  '<svg width="100" height="100"><rect width="100" height="100" fill="red"/></svg>',
);

const graphics1 = new Graphics(context);
const graphics2 = new Graphics(context);

Loading SVGs as Graphics

Instead of passing an SVG string directly, load an SVG file using Assets.load. This returns a GraphicsContext object for creating multiple Graphics instances efficiently.

const svgContext = await Assets.load('path/to.svg', {
  parseAsGraphicsContext: true, // If false, returns a texture instead
});
const myGraphics = new Graphics(svgContext);

Since it's loaded via Assets.load, the result is cached and reused, similar to a texture.

@stackblitz(graphics_svg_file)

Pros and cons

Pros:

• Retains vector scalability (no pixelation when zooming)
• Modifiable after rendering (change colors, strokes, etc.)
• Efficient for simple shapes; fast if SVG structure doesn't change

Cons:

• Expensive to parse initially (complex SVGs with many paths can be slow)
• Higher per-frame cost than a texture for complex geometry

When to use

• Icons and UI elements that need resizing
• A game world that needs to remain crisp as a player zooms in
• Interactive graphics where modifying the SVG dynamically is necessary

SVG rendering considerations

Supported features

PixiJS supports most SVG features that can be rendered in a Canvas 2D context:

Performance considerations

• Complex SVGs: Large or intricate SVGs can slow down rendering startup due to high parsing costs. Use GraphicsContext to cache and reuse parsed data.
• Vector vs. texture: If performance is a concern, use SVGs as textures instead of rendering them as geometry. Textures take more memory but render faster.
• Real-time rendering: Avoid rendering complex SVGs dynamically. Preload and reuse them wherever possible.

Gotchas

• Large SVGs can be slow to parse. Optimize SVGs before using them in PixiJS.
• Texture-based SVGs do not scale cleanly. Use higher resolution if necessary.
• Not all SVG features are supported. Complex filters and text elements may not work as expected.