Improve image ocr

Author: bigbruno

src/bigocrpdf/services/screen_capture.py

@@ -262,13 +262,19 @@ def _run_flameshot(self, cmd: list[str], temp_path: str) -> bool:
         Returns:
             True (flameshot was executed, regardless of success/cancel).
         """
-        result = subprocess.run(cmd, capture_output=True, timeout=60)
-        if result.returncode == 0 and result.stdout:
+        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        try:
+            stdout, stderr = proc.communicate(timeout=60)
+        except subprocess.TimeoutExpired:
+            proc.kill()
+            proc.communicate()
+            return True
+        if proc.returncode == 0 and stdout:
             with open(temp_path, "wb") as f:
-                f.write(result.stdout)
+                f.write(stdout)
         else:
             logger.debug(
-                f"Flameshot exited with code {result.returncode}: {result.stderr.decode().strip()}"
+                f"Flameshot exited with code {proc.returncode}: {stderr.decode().strip()}"
             )
         return True
 
@@ -285,11 +291,17 @@ def _run_standard_tool(self, cmd: list[str]) -> bool | None:
         if subprocess.call(["which", tool_name], stdout=subprocess.DEVNULL) != 0:
             return None
 
-        result = subprocess.run(cmd, capture_output=True, timeout=60)
-        if result.returncode != 0:
+        proc = subprocess.Popen(cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE)
+        try:
+            _stdout, stderr = proc.communicate(timeout=60)
+        except subprocess.TimeoutExpired:
+            proc.kill()
+            proc.communicate()
+            return True
+        if proc.returncode != 0:
             logger.debug(
-                f"{tool_name} exited with code {result.returncode}: "
-                f"{result.stderr.decode().strip()}"
+                f"{tool_name} exited with code {proc.returncode}: "
+                f"{stderr.decode().strip()}"
             )
         return True
 
@@ -341,15 +353,25 @@ def extract_text_from_image(
                 cmd = self._build_ocr_command(temp_img_path, config)
                 logger.info(f"Running image OCR: language={language}")
 
-                proc = subprocess.run(cmd, capture_output=True, text=True, timeout=120)
+                proc = subprocess.Popen(
+                    cmd, stdout=subprocess.PIPE, stderr=subprocess.PIPE, text=True
+                )
+                try:
+                    stdout, stderr = proc.communicate(timeout=120)
+                except subprocess.TimeoutExpired:
+                    proc.kill()
+                    proc.communicate()
+                    logger.error("OCR processing timed out")
+                    self._invoke_callback(None, _("OCR processing timed out."))
+                    return None
 
                 if proc.returncode != 0:
-                    logger.error(f"OCR subprocess failed: {proc.stderr}")
+                    logger.error(f"OCR subprocess failed: {stderr}")
                     self._invoke_callback(None, _("OCR processing failed."))
                     return None
 
                 # Parse OCR results
-                results = self._parse_ocr_results(proc.stdout)
+                results = self._parse_ocr_results(stdout)
                 if not results:
                     return _("No text found in the image")
 
@@ -366,10 +388,6 @@ def extract_text_from_image(
                 None, _("OCR engine not available. Please check your installation.")
             )
             return None
-        except subprocess.TimeoutExpired:
-            logger.error("OCR processing timed out")
-            self._invoke_callback(None, _("OCR processing timed out."))
-            return None
         except (OSError, subprocess.SubprocessError, ValueError) as e:
             logger.error(f"OCR processing error: {e}")
             return None

src/bigocrpdf/utils/temp_manager.py

@@ -11,6 +11,7 @@
 import shutil
 import signal
 import tempfile
+import threading
 from pathlib import Path
 
 from bigocrpdf.utils.logger import logger
@@ -39,18 +40,19 @@ def _register_cleanup() -> None:
 
     atexit.register(cleanup_all)
 
-    # Also handle SIGTERM (e.g. system shutdown, kill <pid>)
-    prev_handler = signal.getsignal(signal.SIGTERM)
+    # SIGTERM handler can only be set from the main thread
+    if threading.current_thread() is threading.main_thread():
+        prev_handler = signal.getsignal(signal.SIGTERM)
 
-    def _on_sigterm(signum, frame):
-        cleanup_all()
-        # Chain to previous handler
-        if callable(prev_handler):
-            prev_handler(signum, frame)
-        else:
-            raise SystemExit(1)
+        def _on_sigterm(signum, frame):
+            cleanup_all()
+            # Chain to previous handler
+            if callable(prev_handler):
+                prev_handler(signum, frame)
+            else:
+                raise SystemExit(1)
 
-    signal.signal(signal.SIGTERM, _on_sigterm)
+        signal.signal(signal.SIGTERM, _on_sigterm)
 
 
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