feat: Modify Wand builder and replace Imagemagick and Pillow with it

* modify image__wand builder so that it is like common thumbnail generation strategies
* deprecate  Pillow and ImageMagick (command line) builder
* add doc about how to enable eps format support

PR ref: #274 
issue ref: #253

README.rst

@@ -214,6 +214,16 @@ Building ImageMagick with heic support: `Building ImageMagick with heic support`
 
 .. _`Building ImageMagick with heic support`: doc/build_im_with_heic_support.rst
 
+EPS support
+~~~~~~~~~~~~
+
+You need to edit the policies of ImageMagick in /etc/ImageMagick-*/policy.xml.
+
+.. code:: xhtml
+
+  <policy domain="coder" rights="none" pattern="ESP" />
+
+Just wrap it between <!-- and --> to comment it.
 
 -----
 Usage

preview_generator/preview/builder/cad__vtk.py

@@ -6,7 +6,7 @@
 from preview_generator.exception import BuilderDependencyNotFound
 from preview_generator.exception import UnsupportedMimeType
 from preview_generator.extension import mimetypes_storage
-from preview_generator.preview.builder.image__pillow import ImagePreviewBuilderPillow  # nopep8
+from preview_generator.preview.builder.image__wand import ImagePreviewBuilderWand  # nopep8
 from preview_generator.preview.generic_preview import PreviewBuilder
 from preview_generator.utils import ImgDims
 from preview_generator.utils import MimetypeMapping
@@ -188,7 +188,7 @@ def build_jpeg_preview(
             writer.SetInputConnection(windowto_image_filter.GetOutputPort())
             writer.Write()
 
-            return ImagePreviewBuilderPillow().build_jpeg_preview(
+            return ImagePreviewBuilderWand().build_jpeg_preview(
                 tmp_png.name, preview_name, cache_path, page_id, extension, size, mimetype
             )
 

preview_generator/preview/builder/document__drawio.py

@@ -7,7 +7,7 @@
 
 from preview_generator.exception import BuilderDependencyNotFound
 from preview_generator.exception import IntermediateFileBuildingFailed
-from preview_generator.preview.builder.image__pillow import ImagePreviewBuilderPillow
+from preview_generator.preview.builder.image__wand import ImagePreviewBuilderWand
 from preview_generator.preview.generic_preview import PreviewBuilder
 from preview_generator.utils import ImgDims
 from preview_generator.utils import MimetypeMapping
@@ -90,7 +90,7 @@ def build_jpeg_preview(
                     "failed with status {}".format(build_jpg_result_code)
                 )
 
-            ImagePreviewBuilderPillow().build_jpeg_preview(
+            ImagePreviewBuilderWand().build_jpeg_preview(
                 tmp_jpg.name, preview_name, cache_path, page_id, extension, size, mimetype
             )
 

preview_generator/preview/builder/document__sketch.py

@@ -3,7 +3,7 @@
 import typing
 import zipfile
 
-from preview_generator.preview.builder.image__pillow import ImagePreviewBuilderPillow  # nopep8
+from preview_generator.preview.builder.image__wand import ImagePreviewBuilderWand  # nopep8
 from preview_generator.preview.generic_preview import PreviewBuilder
 from preview_generator.utils import ImgDims
 from preview_generator.utils import MimetypeMapping
@@ -46,7 +46,7 @@ def build_jpeg_preview(
                 zip.extract("previews/preview.png", tmp_dir)
                 zip.close()
 
-                ImagePreviewBuilderPillow().build_jpeg_preview(
+                ImagePreviewBuilderWand().build_jpeg_preview(
                     tmp_dir + "/previews/preview.png",
                     preview_name,
                     cache_path,

preview_generator/preview/builder/image__cairosvg.py

@@ -5,7 +5,7 @@
 
 # HACK - G.M - 2020-12-26 - Hack to allow loading modules without cairosvg installed
 from preview_generator.exception import BuilderDependencyNotFound
-from preview_generator.preview.builder.image__pillow import ImagePreviewBuilderPillow  # nopep8
+from preview_generator.preview.builder.image__wand import ImagePreviewBuilderWand  # nopep8
 from preview_generator.preview.generic_preview import ImagePreviewBuilder
 from preview_generator.utils import ImgDims
 
@@ -55,7 +55,7 @@ def build_jpeg_preview(
         ) as tmp_png:
             cairosvg.svg2png(url=file_path, write_to=tmp_png.name, dpi=96)
 
-            return ImagePreviewBuilderPillow().build_jpeg_preview(
+            return ImagePreviewBuilderWand().build_jpeg_preview(
                 tmp_png.name, preview_name, cache_path, page_id, extension, size, mimetype
             )
 

preview_generator/preview/builder/image__imconvert.py

@@ -21,7 +21,8 @@
 
 
 class ImagePreviewBuilderIMConvert(ImagePreviewBuilder):
-    """IM means Image Magick"""
+    """WARNING : This builder is deprecated, prefer ImagePreviewBuilderWand instead which
+    support the same list of format."""
 
     MIMETYPES = []  # type: typing.List[str]
     # TODO - G.M - 2019-11-21 - find better storage solution for mimetype mapping
@@ -53,7 +54,7 @@ class ImagePreviewBuilderIMConvert(ImagePreviewBuilder):
         MimetypeMapping("image/heic", ".heif"),
     ]
 
-    weight = 30
+    weight = 0
 
     @classmethod
     def get_label(cls) -> str:

preview_generator/preview/builder/image__inkscape.py

@@ -10,7 +10,7 @@
 
 from preview_generator.exception import BuilderDependencyNotFound
 from preview_generator.exception import IntermediateFileBuildingFailed
-from preview_generator.preview.builder.image__pillow import ImagePreviewBuilderPillow  # nopep8
+from preview_generator.preview.builder.image__wand import ImagePreviewBuilderWand  # nopep8
 from preview_generator.preview.generic_preview import ImagePreviewBuilder
 from preview_generator.utils import ImgDims
 from preview_generator.utils import executable_is_available
@@ -83,6 +83,6 @@ def build_jpeg_preview(
                     "failed with status {}".format(build_png_result_code)
                 )
 
-            return ImagePreviewBuilderPillow().build_jpeg_preview(
+            return ImagePreviewBuilderWand().build_jpeg_preview(
                 tmp_png.name, preview_name, cache_path, page_id, extension, size, mimetype
             )

preview_generator/preview/builder/image__pillow.py

@@ -210,6 +210,9 @@ def get_strategy(self, image: PIL.Image) -> ImageConvertStrategy:
 
 
 class ImagePreviewBuilderPillow(ImagePreviewBuilder):
+    """WARNING : This builder is deprecated, prefer ImagePreviewBuilderWand instead which
+        support the same list of format."""
+
     weight = 20
 
     def __init__(

preview_generator/preview/builder/image__wand.py

@@ -1,27 +1,64 @@
 # -*- coding: utf-8 -*-
-
-from io import BytesIO
+import os
 import typing
 
-from wand.image import Color
-from wand.image import Image as WImage
+from wand.color import Color
+from wand.image import Image
+from wand.exceptions import CoderError, CoderFatalError, CoderWarning
 import wand.version
 
-from preview_generator.preview.builder.image__imconvert import ImagePreviewBuilderIMConvert
+from preview_generator.extension import mimetypes_storage
+from preview_generator.exception import BuilderDependencyNotFound
 from preview_generator.preview.generic_preview import ImagePreviewBuilder
 from preview_generator.utils import ImgDims
+from preview_generator.utils import MimetypeMapping
 from preview_generator.utils import compute_resize_dims
+from preview_generator.utils import executable_is_available
 from preview_generator.utils import imagemagick_supported_mimes
 
+DEFAULT_JPEG_QUALITY = 85
+DEFAULT_JPEG_PROGRESSIVE = True
+
 
 class ImagePreviewBuilderWand(ImagePreviewBuilder):
-    """
-    WARNING : This builder is deprecated, prefer ImagePreviewBuilderIMConvert instead which
-    support the same list of format.
-    """
 
-    weight = 10
+    weight = 30
     MIMETYPES = []  # type: typing.List[str]
+    # TODO - G.M - 2019-11-21 - find better storage solution for mimetype mapping
+    # dict and/or list.
+    # see https://github.com/algoo/preview-generator/pull/148#discussion_r346381508
+    SUPPORTED_RAW_CAMERA_MIMETYPE_MAPPING = [
+        MimetypeMapping("image/x-sony-arw", ".arw"),
+        MimetypeMapping("image/x-adobe-dng", ".dng"),
+        MimetypeMapping("image/x-sony-sr2", ".sr2"),
+        MimetypeMapping("image/x-sony-srf", ".srf"),
+        MimetypeMapping("image/x-sigma-x3f", ".x3f"),
+        MimetypeMapping("image/x-canon-crw", ".crw"),
+        MimetypeMapping("image/x-canon-cr2", ".cr2"),
+        MimetypeMapping("image/x-epson-erf", ".erf"),
+        MimetypeMapping("image/x-fuji-raf", ".raf"),
+        MimetypeMapping("image/x-nikon-nef", ".nef"),
+        MimetypeMapping("image/x-olympus-orf", ".orf"),
+        MimetypeMapping("image/x-panasonic-raw", ".raw"),
+        MimetypeMapping("image/x-panasonic-rw2", ".rw2"),
+        MimetypeMapping("image/x-pentax-pef", ".pef"),
+        MimetypeMapping("image/x-kodak-dcr", ".dcr"),
+        MimetypeMapping("image/x-kodak-k25", ".k25"),
+        MimetypeMapping("image/x-kodak-kdc", ".kdc"),
+        MimetypeMapping("image/x-minolta-mrw", ".mrw"),
+    ]
+
+    SUPPORTED_HEIC_MIMETYPE_MAPPING = [
+        MimetypeMapping("image/heic", ".heic"),
+        MimetypeMapping("image/heic", ".heif"),
+    ]
+
+    def __init__(
+        self, quality: int = DEFAULT_JPEG_QUALITY, progressive: bool = DEFAULT_JPEG_PROGRESSIVE,
+    ):
+        super().__init__()
+        self.quality = quality
+        self.progressive = progressive
 
     @classmethod
     def get_label(cls) -> str:
@@ -37,7 +74,29 @@ def __load_mimetypes(cls) -> typing.List[str]:
         Load supported mimetypes from WAND library
         :return: list of supported mime types
         """
-        return imagemagick_supported_mimes()
+
+        mimes = imagemagick_supported_mimes()  # type: typing.List[str]
+        # HACK - G.M - 2019-10-31 - Handle raw format only if ufraw-batch is installed as most common
+        # default imagemagick configuration delegate raw format to ufraw-batch.
+        if executable_is_available("ufraw-batch"):
+            for mimetype_mapping in cls.SUPPORTED_RAW_CAMERA_MIMETYPE_MAPPING:
+                mimes.append(mimetype_mapping.mimetype)
+        return mimes
+
+    @classmethod
+    def get_mimetypes_mapping(cls) -> typing.List[MimetypeMapping]:
+        mimetypes_mapping = []  # type: typing.List[MimetypeMapping]
+        mimetypes_mapping = (
+            mimetypes_mapping
+            + cls.SUPPORTED_RAW_CAMERA_MIMETYPE_MAPPING
+            + cls.SUPPORTED_HEIC_MIMETYPE_MAPPING
+        )
+        return mimetypes_mapping
+
+    @classmethod
+    def check_dependencies(cls) -> None:
+        if not executable_is_available("convert"):
+            raise BuilderDependencyNotFound("this builder requires convert to be available")
 
     @classmethod
     def get_supported_mimetypes(cls) -> typing.List[str]:
@@ -48,21 +107,9 @@ def get_supported_mimetypes(cls) -> typing.List[str]:
             ImagePreviewBuilderWand.MIMETYPES = cls.__load_mimetypes()
         mimetypes = ImagePreviewBuilderWand.MIMETYPES
 
-        # INFO - G.M - 2021-04-30
-        # Disable support for postscript,xcf and raw image format in wand, to ensure
-        # proper builder is used (either imagemagick convert or pillow)
-
-        invalid_mimetypes = ["application/postscript", "application/x-xcf", "image/x-xcf"]
-        for (
-            mimetype_mapping
-        ) in ImagePreviewBuilderIMConvert().SUPPORTED_RAW_CAMERA_MIMETYPE_MAPPING:
-            invalid_mimetypes.append(mimetype_mapping.mimetype)
-
-        for invalid_mimetype in invalid_mimetypes:
-            try:
-                mimetypes.remove(invalid_mimetype)
-            except ValueError:
-                pass
+        extra_mimetypes = ["application/x-xcf", "image/x-xcf"]
+        mimetypes.extend(extra_mimetypes)
+
         return mimetypes
 
     def build_jpeg_preview(
@@ -77,41 +124,47 @@ def build_jpeg_preview(
     ) -> None:
         if not size:
             size = self.default_size
-        with open(file_path, "rb") as img:
-            result = self.image_to_jpeg_wand(img, ImgDims(width=size.width, height=size.height))
-
-            with open(
-                "{path}{extension}".format(path=cache_path + preview_name, extension=extension),
-                "wb",
-            ) as jpeg:
-                buffer = result.read(1024)
-                while buffer:
-                    jpeg.write(buffer)
-                    buffer = result.read(1024)
-
-    def image_to_jpeg_wand(
-        self, jpeg: typing.Union[str, typing.IO[bytes]], preview_dims: ImgDims
-    ) -> BytesIO:
+        preview_name = preview_name + extension
+        dest_path = os.path.join(cache_path, preview_name)
+        self.image_to_jpeg_wand(file_path, size, dest_path, mimetype=mimetype)
+
+    def image_to_jpeg_wand(self, file_path: str, preview_dims: ImgDims, dest_path: str,
+                           mimetype: typing.Optional[str]) -> None:
+        try:
+            with self._convert_image(file_path, preview_dims) as img:
+                img.save(filename=dest_path)
+        except (CoderError, CoderFatalError, CoderWarning) as e:
+            assert mimetype
+            file_ext = mimetypes_storage.guess_extension(mimetype, strict=False) or ""
+            if file_ext:
+                file_path = file_ext.lstrip(".") + ":" + file_path
+                with self._convert_image(file_path, preview_dims) as img:
+                    img.save(filename=dest_path)
+            else:
+                raise e
+
+    def _convert_image(self, file_path: str, preview_dims: ImgDims) -> Image:
         """
-        for jpeg, gif and bmp
-        :param jpeg:
-        :param size:
-        :return:
+        refer: https://legacy.imagemagick.org/Usage/thumbnails/
+        like cmd: convert -layers merge  -background white -thumbnail widthxheight \
+        -auto-orient -quality 85 -interlace plane input.jpeg output.jpeg
         """
-        self.logger.info("Converting image to jpeg using wand")
-
-        with WImage(file=jpeg, background=Color("white")) as image:
-
-            preview_dims = ImgDims(width=preview_dims.width, height=preview_dims.height)
-
-            resize_dim = compute_resize_dims(
-                dims_in=ImgDims(width=image.size[0], height=image.size[1]), dims_out=preview_dims
-            )
-            image.resize(resize_dim.width, resize_dim.height)
-            # INFO - jumenzel - 2019-03-12 - remove metadata, color-profiles from this image.
-            image.strip()
-            content_as_bytes = image.make_blob("jpeg")
-            output = BytesIO()
-            output.write(content_as_bytes)
-            output.seek(0, 0)
-            return output
+
+        img = Image(filename=file_path)
+        resize_dim = compute_resize_dims(
+            dims_in=ImgDims(width=img.width, height=img.height), dims_out=preview_dims
+        )
+
+        img.auto_orient()
+        img.iterator_reset()
+        img.background_color = Color("white")
+        img.merge_layers("merge")
+
+        if self.progressive:
+            img.interlace_scheme = "plane"
+
+        img.compression_quality = self.quality
+
+        img.thumbnail(resize_dim.width, resize_dim.height)
+
+        return img

preview_generator/preview/builder_factory.py

@@ -108,9 +108,10 @@ def load_builders(self, force: bool = False) -> None:
                 if is_abstract(cls):
                     # INFO - G.M - 2021-06-22 - Skip abstract classes from loaded builders
                     pass
-                elif cls.__name__ == "ImagePreviewBuilderWand":
+                elif cls.__name__ in ("ImagePreviewBuilderPillow", "ImagePreviewBuilderIMConvert"):
                     self.logger.info(
-                        "ImagePreviewBuilderWand builder is deprecated and is not registered by default. Consider using ImagePreviewBuilderIMConvert instead"
+                        "%s builder is deprecated and is not registered by default. "
+                        "Consider using ImagePreviewBuilderIMConvert instead".format(cls.__name__)
                     )
                 else:
                     self.register_builder(cls, overwrite=False)

tests/builders/test_image_wand_builder.py

@@ -0,0 +1,33 @@
+import os
+from PIL import Image
+from preview_generator.preview.builder.image__wand import ImagePreviewBuilderWand
+from preview_generator.preview.builder.image__imconvert import ImagePreviewBuilderIMConvert
+from preview_generator.utils import ImgDims
+
+CURRENT_DIR = os.path.dirname(os.path.abspath(__file__))
+CACHE_DIR = "/tmp/preview-generator-tests/cache"
+
+
+def test_build_jpeg_preview() -> None:
+    wand_builder = ImagePreviewBuilderWand()
+    test_orient_path = os.path.join(CURRENT_DIR, "the_img.png")
+    extension = ".jpg"
+    preview_name = "preview_the_img"
+    width = 512
+    height = 256
+    size = ImgDims(width=width, height=height)
+    wand_builder.build_jpeg_preview(
+        file_path=test_orient_path,
+        preview_name=preview_name,
+        cache_path=CACHE_DIR,
+        page_id=-1,
+        size=size,
+        extension=extension
+    )
+    preview_name = preview_name + extension
+    dest_path = os.path.join(CACHE_DIR, preview_name)
+    assert os.path.exists(dest_path)
+    assert os.path.getsize(dest_path) > 0
+    with Image.open(dest_path) as jpg:
+        assert jpg.height == height
+        assert jpg.width in range(288, 290)