TinyVG

A Nim library for reading and writing TinyVG (Tiny Vector Graphics) files.

TinyVG is a compact, text-based vector graphics format designed for embedded systems and resource-constrained environments.

Features

• Read TinyVG text format files
• Write TinyVG text format files
• Create vector graphics programmatically
• Round-trip support (read → modify → write)
• Support for all TinyVG commands:
• Fill rectangles
• Outline fill rectangles
• Draw lines, line loops, line strips
• Fill polygons
• Draw and fill paths (with Bezier curves, arcs)
• Text hints
• Flexible color styles: flat, linear gradient, radial gradient
• Fractional scale values (e.g., 1/32)

Installation

Install via nimble:

  nimble install tinyvg
  ```

Or add to your `.nimble` file:

```nim
requires "tinyvg >= 0.1.0"

Quick Start

Creating a TinyVG Document

import tinyvg

# Create a new document (width, height, scale)
var doc = initTinyVGDocument(400, 768, 1.0)

# Add colors to the palette
var red = doc.addColor(1.0, 0.0, 0.0)     # RGB
var green = doc.addColor(0.0, 1.0, 0.0)   # RGB
var blue = doc.addColor(0.0, 0.0, 1.0, 0.5)  # RGBA with alpha

# Add a filled rectangle
doc.addFillRectangle(25, 25, 100, 15, red)

# Add an outlined filled rectangle
doc.addOutlineFillRectangle(25, 105, 100, 15, red, green, 2.5)

# Write to file
writeTinyVG(doc, "example.tvg")

Reading a TinyVG Document

import tinyvg

# Read from file
var doc = readTinyVG("example.tvg")

# Access document properties
echo "Width: ", doc.header.width
echo "Height: ", doc.header.height
echo "Colors: ", doc.palette.len
echo "Commands: ", doc.commands.len

Parsing from String

import tinyvg

var tvgText = """
(tvg 1
  (400 768 1/32 u8888 default)
  (
    (1.000 0.000 0.000)
    (0.000 1.000 0.000)
  )
  (
    (
      fill_rectangles
      (flat 0)
      (
        (25 25 100 15)
      )
    )
  )
)
"""

var doc = parseTinyVG(tvgText)

API Reference

Document Creation

• initTinyVGDocument(width, height, scale = 1.0) - Create a new document
• addColor(r, g, b, a = 1.0) - Add a color to the palette, returns color index

Drawing Commands

• addFillRectangle(x, y, width, height, colorIndex) - Add filled rectangle
• addOutlineFillRectangle(x, y, width, height, fillColor, lineColor, lineWidth) - Add outlined filled rectangle

File I/O

• readTinyVG(filename) - Read a TinyVG file
• writeTinyVG(doc, filename) - Write a document to file
• parseTinyVG(text) - Parse TinyVG text format string
• writeTinyVG(doc) - Serialize document to string

Data Types

TinyVGDocument

• header: Document metadata (version, width, height, scale, format)
• palette: Sequence of colors
• commands: Drawing commands

TinyVGColor

• r, g, b, a: Float values (0.0 - 1.0)

TinyVGStyle

• kind: flat, linear, or radial
• flatColorIndex: For flat colors
• linearStartPoint, linearEndPoint, linearStartColorIndex, linearEndColorIndex: For linear gradients
• radialStartPoint, radialEndPoint, radialStartColorIndex, radialEndColorIndex: For radial gradients

TinyVG Format

TinyVG files use a Lisp-like syntax:

(tvg 1                              ; Version 1
  (400 768 1/32 u8888 default)      ; Width, Height, Scale, Format, Precision
  (                                 ; Color palette
    (1.000 0.000 0.000)             ; Red
    (0.000 1.000 0.000)             ; Green
  )
  (                                 ; Commands
    (
      fill_rectangles               ; Command type
      (flat 0)                      ; Style (flat, color index 0)
      (                             ; Rectangles
        (25 25 100 15)              ; x, y, width, height
      )
    )
  )
)

Testing

Run the test suite:

nimble test

License

MIT License - see LICENSE file for details.

See Also

• TinyVG Specification
• TinyVG GitHub