Move WMF image handler to recipes directory

1 files changed, 103 insertions, 0 deletions

diff --git a/recipes/wmf_images.py b/recipes/wmf_images.py
new file mode 100644
index 0000000..afea437
--- /dev/null
+++ b/recipes/wmf_images.py
@@ -0,0 +1,103 @@
+import io
+import os
+import shutil
+import subprocess
+import tempfile
+
+
+# An example of how to use LibreOffice and ImageMagick to convert WMF images to
+# PNGs.
+#
+# libreoffice_wmf_conversion uses LibreOffice to convert the image to a PNG.
+# This normally creates an image with a large amount of padding, so
+# imagemagick_trim can be used to trim the image.
+#
+# The image can be then be converted using a normal image handler, such as
+# mammoth.images.data_uri.
+#
+# Example usage:
+#
+# def convert_image(image):
+#     image = libreoffice_wmf_conversion(image, post_process=imagemagick_trim)
+#     return mammoth.images.data_uri(image)
+#    
+#
+# fileobj = open("document.docx", "rb")
+# result = mammoth.convert_to_html(
+#     fileobj,
+#     convert_image=compose(
+#         mammoth.images.data_uri,
+#         libreoffice_wmf_conversion(post_process=imagemagick_trim),
+#     ),
+# )
+#
+# libreoffice_wmf_conversion uses LibreOffice to convert the image
+
+
+_wmf_extensions = {
+    "image/x-wmf": ".wmf",
+    "image/x-emf": ".emf",
+}
+
+
+def libreoffice_wmf_conversion(image, post_process=None):
+    if post_process is None:
+        post_process = lambda x: x
+    
+    wmf_extension = _wmf_extensions.get(image.content_type)
+    if wmf_extension is None:
+        return image
+    else:
+        temporary_directory = tempfile.mkdtemp()
+        try:
+            input_path = os.path.join(temporary_directory, "image" + wmf_extension)
+            with io.open(input_path, "wb") as input_fileobj:
+                with image.open() as image_fileobj:
+                    shutil.copyfileobj(image_fileobj, input_fileobj)
+            
+            output_path = os.path.join(temporary_directory, "image.png")
+            subprocess.check_call([
+                "libreoffice",
+                "--headless",
+                "--convert-to",
+                "png",
+                input_path,
+                "--outdir",
+                temporary_directory,
+            ])
+            
+            with io.open(output_path, "rb") as output_fileobj:
+                output = output_fileobj.read()
+            
+            def open_image():
+                return io.BytesIO(output)
+            
+            return post_process(image.copy(
+                content_type="image/png",
+                open=open_image,
+            ))
+        finally:
+            shutil.rmtree(temporary_directory)
+
+
+def imagemagick_trim(image):
+    command = ["convert", "-", "-trim", "-"]
+    process = subprocess.Popen(command, stdin=subprocess.PIPE, stdout=subprocess.PIPE)
+    try:
+        with image.open() as image_fileobj:
+            shutil.copyfileobj(image_fileobj, process.stdin)
+        output, err_output = process.communicate()
+    except:
+        process.kill()
+        process.wait()
+        raise
+        
+    return_code = process.poll()
+    if return_code:
+        raise subprocess.CalledProcessError(return_code, command)
+    else:
+        def open_image():
+            return io.BytesIO(output)
+        
+        return image.copy(open=open_image)
+