Corel Photopaint file
application/octet-stream
Magic Bytes
Offset: 0
43 50 54 46 49 4C 45
Corel PHOTO-PAINT (CPT) is a proprietary raster graphics format developed and maintained by Corel Corporation as the native project file for its image editing software. Primarily used within the CorelDRAW Graphics Suite, it preserves multi-layered images, transparency masks, and specific color channels for complex image manipulation. Although the format is considered safe, its proprietary nature restricts compatibility to Corel products or specific third-party tools, necessitating conversion for standard web or print distribution.
Validation Code
How to validate .cpt files in Python
Python
def is_cpt(file_path: str) -> bool:
"""Check if file is a valid CPT by magic bytes."""
signature = bytes([0x43, 0x50, 0x54, 0x46, 0x49, 0x4C, 0x45])
with open(file_path, "rb") as f:
return f.read(7) == signatureHow to validate .cpt files in Node.js
Node.js
function isCPT(buffer: Buffer): boolean {
const signature = Buffer.from([0x43, 0x50, 0x54, 0x46, 0x49, 0x4C, 0x45]);
return buffer.subarray(0, 7).equals(signature);
}
Go
func IsCPT(data []byte) bool {
signature := []byte{0x43, 0x50, 0x54, 0x46, 0x49, 0x4C, 0x45}
if len(data) < 7 {
return false
}
return bytes.Equal(data[:7], signature)
}API Endpoint
GET
/api/v1/cpt
curl https://filesignature.org/api/v1/cpt