Merge pull request #155 from aradhyacp/fix/png-PCRT-issue

fix: PCRT repaired PNG files corruption and filename extension #152

aperisolve/analyzers/pcrt.py

@@ -18,7 +18,7 @@ class PCRTAnalyzer(SubprocessAnalyzer):
 
     def _write_repaired_data(self, data: bytes) -> str:
         """Write recovered image."""
-        img_name = f"pcrt_recoverd_{self.input_img.name}.png"
+        img_name = f"pcrt_recovered_{self.input_img.stem}.png"
         output_path = self.output_dir / img_name
         saved_img_url = "/image/" + str(Path(self.output_dir.name) / img_name)
         with output_path.open("wb") as f:

aperisolve/utils/png.py

@@ -57,8 +57,9 @@ class PNG:
         pos = data.find(b"IHDR")
         if pos == -1:
             return -1, b""
-        idat_begin = data.find(b"IDAT")
-        return pos, data[pos - 4 : idat_begin - 4 if idat_begin != -1 else pos + 21]
+        # IHDR chunk is always 25 bytes: 4 (length) + 4 (type) + 13 (data) + 4 (CRC)
+        # Only return the IHDR chunk itself, not everything up to IDAT
+        return pos, data[pos - 4 : pos + 21]
 
     def check_header(self) -> bool:
         """Check and fix PNG header."""