CGM
image/cgm
Magic Bytes
Offset: 0
42 45 47 4D 46
Computer Graphics Metafile (CGM) is an international standard maintained by ISO and IEC for the representation of 2D vector and raster graphics. It is widely utilized in technical fields such as aeronautics, engineering, and architectural design for exchanging complex CAD illustrations and high-precision diagrams between disparate computer systems. Although largely superseded by modern standards like SVG, CGM persists as a critical legacy format for industrial documentation and specialized scientific visualization due to its robust stability.
Validation Code
How to validate .cgm files in Python
Python
def is_cgm(file_path: str) -> bool:
"""Check if file is a valid CGM by magic bytes."""
signature = bytes([0x42, 0x45, 0x47, 0x4D, 0x46])
with open(file_path, "rb") as f:
return f.read(5) == signatureHow to validate .cgm files in Node.js
Node.js
function isCGM(buffer: Buffer): boolean {
const signature = Buffer.from([0x42, 0x45, 0x47, 0x4D, 0x46]);
return buffer.subarray(0, 5).equals(signature);
}
Go
func IsCGM(data []byte) bool {
signature := []byte{0x42, 0x45, 0x47, 0x4D, 0x46}
if len(data) < 5 {
return false
}
return bytes.Equal(data[:5], signature)
}API Endpoint
GET
/api/v1/cgm
curl https://filesignature.org/api/v1/cgm