ICO
Icon File Format
A file format for icons on Windows and the web (favicon), containing multiple sizes and color depths in one file.
التفاصيل التقنية
Understanding ico requires knowledge of file structure — how headers, metadata, and payload data are organized within the binary layout. Most file formats begin with a magic number (signature bytes) that identifies the format independently of the file extension: PDF starts with %PDF-, PNG with \x89PNG, ZIP with PK. MIME type detection combines magic number inspection with file extension matching. Format specifications define the exact byte layout, enabling tools to parse, validate, and convert files correctly.
مثال
```javascript
// ICO: file format detection
const header = new Uint8Array(await file.slice(0, 4).arrayBuffer());
const signature = Array.from(header).map(b => b.toString(16)).join(' ');
// PDF: '25 50 44 46' (%PDF)
// PNG: '89 50 4e 47' (.PNG)
// ZIP: '50 4b 03 04' (PK..)
```