interface PotraceOptions {
turnPolicy?: string;
turdSize?: number;
alphaMax?: number;
optCurve?: boolean;
optTolerance?: number;
}
interface Potrace {
trace: (
input: Buffer,
options: PotraceOptions,
callback: (err: Error | null, svg: string) => void
) => void;
}
let potraceModule: any = null;
async function loadPotrace(): Promise<Potrace> {
if (!potraceModule) {
potraceModule = await import('potrace');
}
return potraceModule.default || potraceModule;
}
const MAX_TRACEABLE_DIMENSION = 256;
const TRACE_TIMEOUT_MS = 5000;
const POTRACE_CONFIG = {
turnPolicy: 'minority',
turdSize: 2,
alphaMax: 1.0,
optCurve: true,
optTolerance: 0.2,
};
function base64ToBuffer(base64String: string): Buffer {
const matches = base64String.match(/^data:image\/png;base64,(.*)$/);
const base64Data = matches ? matches[1] : base64String;
return Buffer.from(base64Data, 'base64');
}
function createEmbeddedSvg(pngBase64: string, width: number, height: number): string {
const dataUri = pngBase64.includes('data:image/png;base64,')
? pngBase64
: `data:image/png;base64,${pngBase64}`;
return `<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 ${width} ${height}" width="${width}" height="${height}"><image href="${dataUri}" width="${width}" height="${height}"/></svg>`;
}
async function traceWithTimeout(buffer: Buffer): Promise<string> {
const potrace = await loadPotrace();
return new Promise((resolve, reject) => {
const timeoutId = setTimeout(() => {
reject(new Error('Potrace timeout exceeded'));
}, TRACE_TIMEOUT_MS);
potrace.trace(buffer, POTRACE_CONFIG, (err: Error | null, svg: string) => {
clearTimeout(timeoutId);
if (err) {
reject(err);
} else {
resolve(svg);
}
});
});
}
export async function convertPngToVectorizedSvg(
pngBase64: string,
width: number,
height: number
): Promise<string> {
try {
if (width > MAX_TRACEABLE_DIMENSION || height > MAX_TRACEABLE_DIMENSION) {
return createEmbeddedSvg(pngBase64, width, height);
}
const buffer = base64ToBuffer(pngBase64);
const svg = await traceWithTimeout(buffer);
return svg;
} catch (error) {
const errorMessage = error instanceof Error ? error.message : 'Unknown error during vectorization';
console.warn(`Failed to vectorize image: ${errorMessage}. Using embedded PNG fallback.`);
return createEmbeddedSvg(pngBase64, width, height);
}
}
export function compressPng(pngBase64: string): string {
return pngBase64;
}
export function minifySvg(svgString: string): string {
return svgString
.replace(/<!--[\s\S]*?-->/g, '')
.replace(/>\s+</g, '><')
.replace(/\s{2,}/g, ' ')
.trim();
}
export function optimizeWebp(pngBase64: string): string {
return pngBase64;
}
