tau-dev / tvg

A new format for vector graphics: Tiny vector graphics

.tvg: Tiny Vector Graphics

A new format for simple vector graphics.

Why?

Quoting the german Wikipedia on SVG:

Praktisch alle relevanten Webbrowser können einen Großteil des Sprachumfangs darstellen.

Translated:

Virtually all relevant web browsers can display most of the language specification.

SVG is a horribly complex format, allowing the embedding of JavaScript and other features no sane person ever wants to have in their images. Other relevant vector graphics formats do not exit or don't have a documentation or specification (looking at you, HVIF!).

This project tries to create and specify a new vector format suitable for:

• Small and medium icons (think toolbar, buttons, …)
• Low complexity graphics (think graphs, diagrams, …)
• Embedded platforms (low resource requirements)

Project Goals

Create a vector graphics format that fulfils the following requirements:

• Binary encoded
• Small file size (must be smaller than equivalent bitmaps or SVG graphics)
• Can be rendered without floating point support (suitable for embedded)
• Can be rendered efficiently with modern GPUs (suitable for PC, games)
• Supports the following drawing primitives:
  • points / circles
  • lines
  • triangles / polygons
• Support drawing styles
  • filled
  • outline
  • filled with outline
• Support
  • flat colors
  • bitmap textures
  • linear gradients
  • line widths
• Can use hinting to allow really small rendering (16²)

Use Cases

The use cases here are listed to be considered while working on the specification and give the project a shape and boundary:

• Application Icons (large, fine details)
• Toolbar Icons (small, simple)
• Graphs (large structure, no details, text, think graphviz)
• Diagrams (colored surfaces, text, lines)
• Mangas/Comics (complex shapes, different line thickness)

Project Status

This project is currently work-in-progress and there's neither a specification or a reference implementation. Consider this a mind-experiment for now

See the following documents:

• Specification
• Textual Representation

See also this image to have a preview of what is already implemented:

Considerations

• Which color format does TVG use?
  • Linear color space?
  • sRGB?
• What is the default color depth?
  • 15/16 bit?
  • 24 bit?
  • 30 bit?
• How should font rendering work?
  • Embed vector fonts in the file?
    • Sparse font mapping: Only map glyphs actually used
  • Just render out text as path/line data?
  • SVG shows that not embedding a font makes the file completly unportable and will look different in every renderer. This needs to be prevented
  • Use UTF-8 encoding

Resources

• CSS Gradients
  • Radial and conic gradients can be used for nice 3D shading
• Previous Work: TurtleFont is a pure line-drawing vector format