A TypeScript library for parsing AutoCAD SHX font files. It is ported from this project written by C#. This project fixed many bugs on the original parser. Moreover, support parsing extended big font.
If you are interested in the format of SHX font, please refer to this document.
- Parse SHX font files and extract font data
- Support for various SHX font types:
- Shapes
- Bigfont (including Extended Big Font)
- Unifont
- Shape parsing with performance optimization:
- On-demand parsing
- Shape caching by character code and size
- Modern TypeScript implementation
- Object-oriented design
- Comprehensive test coverage
Using npm:
npm install @mlightcad/shx-parserUsing pnpm:
pnpm add @mlightcad/shx-parserUsing yarn:
yarn add @mlightcad/shx-parserThe demo app is provided with a web-based interface for viewing and exploring SHX font files with the following features:
-
Dual Loading Modes:
- Upload local SHX files
- Select from a remote font library
-
Main Features:
- View all characters in a responsive grid layout
- Search characters by code (decimal/hex)
- Click characters to see them in a larger modal view
- Toggle between decimal and hexadecimal code display
-
Display Information:
- Shows font type, version, and character count
- Renders characters as SVG graphics
- Responsive grid layout that works on different screen sizes
import { ShxFont } from '@mlightcad/shx-parser';
// Load the font file
const fontFileData = /* ArrayBuffer containing SHX font file data */;
const font = new ShxFont(fontFileData);
// Get shape for a character
const charCode = 65; // ASCII code for 'A'
const fontSize = 12;
const shape = font.getCharShape(charCode, fontSize);
if (shape) {
console.log(shape.polylines); // Array of polylines representing the character
console.log(shape.lastPoint); // End point of the character
}
// Clean up resources when done
font.release();The main class for working with SHX fonts.
class ShxFont {
fontData: ShxFontData;
constructor(data: ArrayBuffer);
getCharShape(charCode: number, size: number): ShxShape | null;
release(): void;
}Represents a parsed character shape.
interface ShxShape {
polylines: Array<{ x: number; y: number }[]>; // Array of polyline points
lastPoint: { x: number; y: number }; // End point of the shape
}The library parses SHX font files into the following structure:
interface ShxFontData {
header: {
fontType: ShxFontType; // 'shapes' | 'bigfont' | 'unifont'
fileHeader: string; // Font file header information
fileVersion: string; // Font file version
};
content: {
data: Record<number, Uint8Array>; // Character code to bitmap data mapping
info: string; // Additional font information
orientation: string; // Text orientation ('horizontal' | 'vertical')
baseUp: number; // Pixels above baseline
baseDown: number; // Pixels below baseline
isExtended: boolean; // Flag to indicate if the font is an extended big font
};
}import { readFile } from 'fs/promises';
import { ShxFont } from '@mlightcad/shx-parser';
async function loadFont(filePath: string) {
const buffer = await readFile(filePath);
const font = new ShxFont(buffer.buffer);
// Display font information
const fontData = font.fontData;
console.log('Font Information:');
console.log('----------------');
console.log('Font Type:', fontData.header.fontType);
console.log('Header:', fontData.header.fileHeader);
console.log('Version:', fontData.header.fileVersion);
console.log('Info:', fontData.content.info);
console.log('Orientation:', fontData.content.orientation);
console.log('Base Up:', fontData.content.baseUp);
console.log('Base Down:', fontData.content.baseDown);
console.log('Number of shapes:', Object.keys(fontData.content.data).length);
return font;
}function shapeToSvgPath(shape: ShxShape, x: number = 0, y: number = 0): string {
if (!shape?.polylines.length) return '';
return shape.polylines.map(polyline => {
if (!Array.isArray(polyline) || polyline.length === 0) return '';
return polyline.map((point, i) => {
const scaledX = (Number(point.x) || 0) + x;
const scaledY = -(Number(point.y) || 0) + y; // Flip Y coordinate for SVG
const command = i === 0 ? 'M' : 'L';
return `${command} ${scaledX.toFixed(2)} ${scaledY.toFixed(2)}`;
}).join(' ');
}).filter(Boolean).join(' ');
}interface SvgOptions {
width?: number;
height?: number;
strokeWidth?: string;
strokeColor?: string;
isAutoFit?: boolean;
}
function renderTextToSvg(
font: ShxFont,
text: string,
size: number,
options: SvgOptions = {}
): SVGElement {
const {
width = 1000,
height = 1000,
strokeWidth = '0.1%',
strokeColor = 'black',
isAutoFit = false
} = options;
// Create SVG element
const svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
svg.setAttribute('width', width.toString());
svg.setAttribute('height', height.toString());
svg.setAttribute('viewBox', `0 0 ${width} ${height}`);
const padding = size;
let currentX = padding;
let maxHeight = 0;
// Process each character
for (const char of text) {
const charCode = char.charCodeAt(0);
const shape = font.getCharShape(charCode, size);
if (shape) {
const group = document.createElementNS('http://www.w3.org/2000/svg', 'g');
if (isAutoFit) {
// Auto-fit positioning
const bbox = shape.bbox;
const padding = 0.2; // 20% padding
const width = bbox.maxX - bbox.minX;
const height = bbox.maxY - bbox.minY;
const centerX = (bbox.minX + bbox.maxX) / 2;
const centerY = (bbox.minY + bbox.maxY) / 2;
group.setAttribute('transform', `translate(${currentX - centerX}, ${-centerY})`);
} else {
// Fixed positioning
group.setAttribute('transform', `translate(${currentX + width / 2}, ${height / 2})`);
}
// Create path for the character
const pathData = shapeToSvgPath(shape);
const path = document.createElementNS('http://www.w3.org/2000/svg', 'path');
path.setAttribute('d', pathData);
path.setAttribute('fill', 'none');
path.setAttribute('stroke', strokeColor);
path.setAttribute('stroke-width', strokeWidth);
group.appendChild(path);
svg.appendChild(group);
// Update position for next character
if (shape.lastPoint) {
currentX += shape.lastPoint.x + size * 0.5;
} else {
currentX += size;
}
maxHeight = Math.max(maxHeight, size);
}
}
return svg;
}
// Example usage:
async function main() {
try {
const font = await loadFont('path/to/your/font.shx');
// Example 1: Basic rendering
const svgElement1 = renderTextToSvg(font, "Hello", 12);
document.body.appendChild(svgElement1);
// Example 2: Auto-fit rendering with custom options
const svgElement2 = renderTextToSvg(font, "Hello", 12, {
width: 1000,
height: 1000,
strokeWidth: '0.1%',
strokeColor: 'black',
isAutoFit: true
});
document.body.appendChild(svgElement2);
// Clean up resources when done
font.release();
} catch (error) {
console.error('Error:', error instanceof Error ? error.message : 'An unknown error occurred');
}
}Contributions are welcome! Please feel free to submit a Pull Request. For major changes, please open an issue first to discuss what you would like to change.
- Fork the repository
- Create your feature branch (
git checkout -b feature/amazing-feature) - Commit your changes (
git commit -m 'Add some amazing feature') - Push to the branch (
git push origin feature/amazing-feature) - Open a Pull Request
Please make sure to update tests as appropriate.
This project is licensed under the MIT License - see the LICENSE file for details.
If you have any questions or run into issues, please:
- Check the GitHub Issues page
- Open a new issue if your problem hasn't been reported yet