nixpkgs/pkgs/development/python-modules/pyocr-tesseract.patch

This patch is required for pyocr to work with Tesseract version 3.05.00
and has been submitted upstream at the following URL:

https://github.com/jflesch/pyocr/pull/62

diff --git a/src/pyocr/builders.py b/src/pyocr/builders.py
index 73c964d..20f390c 100644
--- a/src/pyocr/builders.py
+++ b/src/pyocr/builders.py
@@ -240,8 +240,10 @@ class BaseBuilder(object):
         cuneiform_args : Arguments passed to the Cuneiform command line.
     """
 
-    def __init__(self, file_extensions, tesseract_configs, cuneiform_args):
+    def __init__(self, file_extensions, tesseract_flags, tesseract_configs,
+                 cuneiform_args):
         self.file_extensions = file_extensions
+        self.tesseract_flags = tesseract_flags
         self.tesseract_configs = tesseract_configs
         self.cuneiform_args = cuneiform_args
 
@@ -298,7 +300,7 @@ class TextBuilder(BaseBuilder):
     def __init__(self, tesseract_layout=3, cuneiform_dotmatrix=False,
                  cuneiform_fax=False, cuneiform_singlecolumn=False):
         file_ext = ["txt"]
-        tess_conf = ["-psm", str(tesseract_layout)]
+        tess_flags = ["-psm", str(tesseract_layout)]
         cun_args = ["-f", "text"]
         # Add custom cuneiform parameters if needed
         for par, arg in [(cuneiform_dotmatrix, "--dotmatrix"),
@@ -306,7 +308,7 @@ class TextBuilder(BaseBuilder):
                          (cuneiform_singlecolumn, "--singlecolumn")]:
             if par:
                 cun_args.append(arg)
-        super(TextBuilder, self).__init__(file_ext, tess_conf, cun_args)
+        super(TextBuilder, self).__init__(file_ext, tess_flags, [], cun_args)
         self.tesseract_layout = tesseract_layout
         self.built_text = []
 
@@ -540,9 +542,11 @@ class WordBoxBuilder(BaseBuilder):
 
     def __init__(self, tesseract_layout=1):
         file_ext = ["html", "hocr"]
-        tess_conf = ["hocr", "-psm", str(tesseract_layout)]
+        tess_flags = ["-psm", str(tesseract_layout)]
+        tess_conf = ["hocr"]
         cun_args = ["-f", "hocr"]
-        super(WordBoxBuilder, self).__init__(file_ext, tess_conf, cun_args)
+        super(WordBoxBuilder, self).__init__(file_ext, tess_flags, tess_conf,
+                                             cun_args)
         self.word_boxes = []
         self.tesseract_layout = tesseract_layout
 
@@ -614,9 +618,11 @@ class LineBoxBuilder(BaseBuilder):
 
     def __init__(self, tesseract_layout=1):
         file_ext = ["html", "hocr"]
-        tess_conf = ["hocr", "-psm", str(tesseract_layout)]
+        tess_flags = ["-psm", str(tesseract_layout)]
+        tess_conf = ["hocr"]
         cun_args = ["-f", "hocr"]
-        super(LineBoxBuilder, self).__init__(file_ext, tess_conf, cun_args)
+        super(LineBoxBuilder, self).__init__(file_ext, tess_flags, tess_conf,
+                                             cun_args)
         self.lines = []
         self.tesseract_layout = tesseract_layout
 
diff --git a/src/pyocr/libtesseract/tesseract_raw.py b/src/pyocr/libtesseract/tesseract_raw.py
index 0c2259a..f7ab309 100644
--- a/src/pyocr/libtesseract/tesseract_raw.py
+++ b/src/pyocr/libtesseract/tesseract_raw.py
@@ -263,11 +263,22 @@ if g_libtesseract:
     ]
     g_libtesseract.TessDeleteText.restype = None
 
-    g_libtesseract.TessBaseAPIDetectOS.argtypes = [
-        ctypes.c_void_p,  # TessBaseAPI*
-        ctypes.POINTER(OSResults),
-    ]
-    g_libtesseract.TessBaseAPIDetectOS.restype = ctypes.c_bool
+    if hasattr(g_libtesseract, 'TessBaseAPIDetectOrientationScript'):
+        g_libtesseract.TessBaseAPIDetectOrientationScript.argtypes = [
+            ctypes.c_void_p,  # TessBaseAPI*
+            ctypes.POINTER(ctypes.c_int),  # orient_deg
+            ctypes.POINTER(ctypes.c_float),  # orient_conf
+            ctypes.POINTER(ctypes.c_char_p),  # script_name
+            ctypes.POINTER(ctypes.c_float),  # script_conf
+        ]
+        g_libtesseract.TessBaseAPIDetectOrientationScript.restype = \
+            ctypes.c_bool
+    else:
+        g_libtesseract.TessBaseAPIDetectOS.argtypes = [
+            ctypes.c_void_p,  # TessBaseAPI*
+            ctypes.POINTER(OSResults),
+        ]
+        g_libtesseract.TessBaseAPIDetectOS.restype = ctypes.c_bool
 
 
 def init(lang=None):
@@ -526,15 +537,37 @@ def detect_os(handle):
     global g_libtesseract
     assert(g_libtesseract)
 
-    results = OSResults()
-    r = g_libtesseract.TessBaseAPIDetectOS(
-        ctypes.c_void_p(handle),
-        ctypes.pointer(results)
-    )
-    if not r:
-        raise TesseractError("detect_orientation failed",
-                             "TessBaseAPIDetectOS() failed")
-    return {
-        "orientation": results.best_orientation_id,
-        "confidence": results.best_oconfidence,
-    }
+    # Use the new API function if it is available, because since Tesseract
+    # 3.05.00 the old API function _always_ returns False.
+    if hasattr(g_libtesseract, 'TessBaseAPIDetectOrientationScript'):
+        orientation_deg = ctypes.c_int(0)
+        orientation_confidence = ctypes.c_float(0.0)
+
+        r = g_libtesseract.TessBaseAPIDetectOrientationScript(
+            ctypes.c_void_p(handle),
+            ctypes.byref(orientation_deg),
+            ctypes.byref(orientation_confidence),
+            None,  # script_name
+            None  # script_confidence
+        )
+
+        if not r:
+            raise TesseractError("detect_orientation failed",
+                                 "TessBaseAPIDetectOrientationScript() failed")
+        return {
+            "orientation": round(orientation_deg.value / 90),
+            "confidence": orientation_confidence.value,
+        }
+    else:  # old API (before Tesseract 3.05.00)
+        results = OSResults()
+        r = g_libtesseract.TessBaseAPIDetectOS(
+            ctypes.c_void_p(handle),
+            ctypes.pointer(results)
+        )
+        if not r:
+            raise TesseractError("detect_orientation failed",
+                                 "TessBaseAPIDetectOS() failed")
+        return {
+            "orientation": results.best_orientation_id,
+            "confidence": results.best_oconfidence,
+        }
diff --git a/src/pyocr/tesseract.py b/src/pyocr/tesseract.py
index 99b0121..658c96b 100755
--- a/src/pyocr/tesseract.py
+++ b/src/pyocr/tesseract.py
@@ -22,6 +22,8 @@ import os
 import subprocess
 import sys
 import tempfile
+import contextlib
+import shutil
 
 from . import builders
 from . import error
@@ -62,9 +64,11 @@ class CharBoxBuilder(builders.BaseBuilder):
 
     def __init__(self):
         file_ext = ["box"]
+        tess_flags = []
         tess_conf = ["batch.nochop", "makebox"]
         cun_args = []
-        super(CharBoxBuilder, self).__init__(file_ext, tess_conf, cun_args)
+        super(CharBoxBuilder, self).__init__(file_ext, tess_flags, tess_conf,
+                                             cun_args)
         self.tesseract_layout = 1
 
     @staticmethod
@@ -173,18 +177,19 @@ def detect_orientation(image, lang=None):
         TesseractError --- if no script detected on the image
     """
     _set_environment()
-    with temp_file(".bmp") as input_file:
-        command = [TESSERACT_CMD, input_file.name, 'stdout', "-psm", "0"]
+    with temp_dir() as tmpdir:
+        command = [TESSERACT_CMD, "input.bmp", 'stdout', "-psm", "0"]
         if lang is not None:
             command += ['-l', lang]
 
         if image.mode != "RGB":
             image = image.convert("RGB")
-        image.save(input_file.name)
+        image.save(os.path.join(tmpdir, "input.bmp"))
 
         proc = subprocess.Popen(command, stdin=subprocess.PIPE, shell=False,
                                 startupinfo=g_subprocess_startup_info,
                                 creationflags=g_creation_flags,
+                                cwd=tmpdir,
                                 stdout=subprocess.PIPE,
                                 stderr=subprocess.STDOUT)
         proc.stdin.close()
@@ -224,8 +229,8 @@ def get_available_builders():
     ]
 
 
-def run_tesseract(input_filename, output_filename_base, lang=None,
-                  configs=None):
+def run_tesseract(input_filename, output_filename_base, cwd=None, lang=None,
+                  flags=None, configs=None):
     '''
     Runs Tesseract:
         `TESSERACT_CMD` \
@@ -238,6 +243,8 @@ def run_tesseract(input_filename, output_filename_base, lang=None,
         input_filename --- image to read
         output_filename_base --- file name in which must be stored the result
             (without the extension)
+        cwd --- Run Tesseract in the specified working directory or use current
+            one if None
         lang --- Tesseract language to use (if None, none will be specified)
         config --- List of Tesseract configs to use (if None, none will be
             specified)
@@ -252,10 +259,13 @@ def run_tesseract(input_filename, output_filename_base, lang=None,
     if lang is not None:
         command += ['-l', lang]
 
+    if flags is not None:
+        command += flags
+
     if configs is not None:
         command += configs
 
-    proc = subprocess.Popen(command,
+    proc = subprocess.Popen(command, cwd=cwd,
                             startupinfo=g_subprocess_startup_info,
                             creationflags=g_creation_flags,
                             stdout=subprocess.PIPE,
@@ -301,11 +311,18 @@ class ReOpenableTempfile(object):
             self.name = None
 
 
-def temp_file(suffix):
-    ''' Returns a temporary file '''
-    if os.name == 'nt':  # Windows
-        return ReOpenableTempfile(suffix)
-    return tempfile.NamedTemporaryFile(prefix='tess_', suffix=suffix)
+@contextlib.contextmanager
+def temp_dir():
+    """
+    A context manager for maintaining a temporary directory
+    """
+    # NOTE: Drop this as soon as we don't support Python 2.7 anymore, because
+    # since Python 3.2 there is a context manager called TemporaryDirectory().
+    path = tempfile.mkdtemp(prefix='tess_')
+    try:
+        yield path
+    finally:
+        shutil.rmtree(path)
 
 
 def image_to_string(image, lang=None, builder=None):
@@ -329,23 +346,20 @@ def image_to_string(image, lang=None, builder=None):
 
     if builder is None:
         builder = builders.TextBuilder()
-    with temp_file(".bmp") as input_file:
-        with temp_file('') as output_file:
-            output_file_name_base = output_file.name
-
+    with temp_dir() as tmpdir:
         if image.mode != "RGB":
             image = image.convert("RGB")
-        image.save(input_file.name)
-        (status, errors) = run_tesseract(input_file.name,
-                                         output_file_name_base,
+        image.save(os.path.join(tmpdir, "input.bmp"))
+        (status, errors) = run_tesseract("input.bmp", "output", cwd=tmpdir,
                                          lang=lang,
+                                         flags=builder.tesseract_flags,
                                          configs=builder.tesseract_configs)
         if status:
             raise TesseractError(status, errors)
 
         output_file_name = "ERROR"
         for file_extension in builder.file_extensions:
-            output_file_name = ('%s.%s' % (output_file_name_base,
+            output_file_name = ('%s.%s' % (os.path.join(tmpdir, "output"),
                                            file_extension))
             if not os.access(output_file_name, os.F_OK):
                 continue
diff --git a/tests/tests_libtesseract.py b/tests/tests_libtesseract.py
index ccddd07..1ac2a4b 100644
--- a/tests/tests_libtesseract.py
+++ b/tests/tests_libtesseract.py
@@ -33,8 +33,9 @@ class TestContext(unittest.TestCase):
             (3, 3, 0),
             (3, 4, 0),
             (3, 4, 1),
+            (3, 5, 0),
         ), ("Tesseract does not have the expected version"
-            " (3.4.0) ! Some tests will be skipped !"))
+            " (3.5.0) ! Some tests will be skipped !"))
 
     def test_langs(self):
         langs = libtesseract.get_available_languages()
diff --git a/tests/tests_tesseract.py b/tests/tests_tesseract.py
index e29c512..fa4d483 100644
--- a/tests/tests_tesseract.py
+++ b/tests/tests_tesseract.py
@@ -27,8 +27,9 @@ class TestContext(unittest.TestCase):
             (3, 3, 0),
             (3, 4, 0),
             (3, 4, 1),
+            (3, 5, 0),
         ), ("Tesseract does not have the expected version"
-            " (3.4.0) ! Some tests will be skipped !"))
+            " (3.5.0) ! Some tests will be skipped !"))
 
     def test_langs(self):
         langs = tesseract.get_available_languages()