Add utility to fetch and prepare ZIM illustration ; make this utility directly accessible from illustration metadata

CHANGELOG.md

@@ -11,6 +11,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 - Upgrade to wombat 3.8.11 (#256)
 
+### Added
+
+- Add utility to fetch and prepare ZIM illustration ; make this utility directly accessible from illustration metadata (#254)
+
 ## [5.1.1] - 2025-02-17
 
 ### Changed

src/zimscraperlib/constants.py

@@ -29,3 +29,6 @@
 # default timeout to get responses from upstream when doing web requests ; this is not
 # the total time it gets to download the whole resource
 DEFAULT_WEB_REQUESTS_TIMEOUT = 10
+
+DEFAULT_ZIM_ILLLUSTRATION_SIZE = 48
+DEFAULT_ZIM_ILLLUSTRATION_SCALE = 1

src/zimscraperlib/image/illustration.py

@@ -0,0 +1,52 @@
+import io
+import pathlib
+
+from zimscraperlib.constants import DEFAULT_ZIM_ILLLUSTRATION_SIZE
+from zimscraperlib.image.conversion import convert_image, convert_svg2png
+from zimscraperlib.image.optimization import optimize_png
+from zimscraperlib.image.probing import format_for
+from zimscraperlib.image.transformation import resize_image
+from zimscraperlib.inputs import handle_user_provided_file
+
+
+def get_zim_illustration(
+    illustration_location: pathlib.Path | str,
+    width: int = DEFAULT_ZIM_ILLLUSTRATION_SIZE,
+    height: int = DEFAULT_ZIM_ILLLUSTRATION_SIZE,
+    resize_method: str = "contain",
+) -> io.BytesIO:
+    """Get ZIM-ready illustration from any image path or URL
+
+    illustration_location will be downloaded if needed. Image is automatically
+    converted to PNG, resized and optimized as needed.
+
+    Arguments:
+        illustration_location: path or URL to an image
+        width: target illustration width
+        height: target illustration height
+        resize_method: method to resize the image ; in general only 'contain' or
+          'cover' make sense, but 'crop', 'width', 'height' and 'thumbnail' can be used
+    """
+
+    illustration_path = handle_user_provided_file(illustration_location)
+
+    if not illustration_path:
+        # given handle_user_provided_file logic, this is not supposed to happen besides
+        # when empty string is passed, hence the simple error message
+        raise ValueError("Illustration is missing")
+
+    illustration = io.BytesIO()
+    illustration_format = format_for(illustration_path, from_suffix=False)
+    if illustration_format == "SVG":
+        convert_svg2png(illustration_path, illustration, width, height)
+    else:
+        if illustration_format != "PNG":
+            convert_image(illustration_path, illustration, fmt="PNG")
+        else:
+            illustration = io.BytesIO(illustration_path.read_bytes())
+        resize_image(illustration, width, height, method=resize_method)
+
+    optimized_illustration = io.BytesIO()
+    optimize_png(illustration, optimized_illustration)
+
+    return optimized_illustration

src/zimscraperlib/zim/metadata.py

@@ -1,6 +1,7 @@
 import base64
 import datetime
 import io
+import pathlib
 from abc import ABC, abstractmethod
 from collections.abc import Iterable
 from dataclasses import asdict, dataclass, fields
@@ -10,12 +11,15 @@
 import regex
 
 from zimscraperlib.constants import (
+    DEFAULT_ZIM_ILLLUSTRATION_SCALE,
+    DEFAULT_ZIM_ILLLUSTRATION_SIZE,
     ILLUSTRATIONS_METADATA_RE,
     MAXIMUM_DESCRIPTION_METADATA_LENGTH,
     MAXIMUM_LONG_DESCRIPTION_METADATA_LENGTH,
     RECOMMENDED_MAX_TITLE_LENGTH,
 )
 from zimscraperlib.i18n import is_valid_iso_639_3
+from zimscraperlib.image.illustration import get_zim_illustration
 from zimscraperlib.image.probing import is_valid_image
 from zimscraperlib.inputs import unique_values
 from zimscraperlib.typing import SupportsRead, SupportsSeekableRead
@@ -352,12 +356,20 @@ class IllustrationBasedMetadata(Metadata):
     meta_mimetype = "image/png"
 
     def __init__(
-        self, value: bytes | io.IOBase | io.BytesIO, name: str | None = None
+        self,
+        value: bytes | io.IOBase | io.BytesIO | str | pathlib.Path,
+        name: str | None = None,
     ) -> None:
         super().__init__(value=value, name=name)
 
     # native type is PNG image buffer
-    def get_cleaned_value(self, value: bytes | io.IOBase | io.BytesIO) -> bytes:
+    def get_cleaned_value(
+        self, value: bytes | io.IOBase | io.BytesIO | str | pathlib.Path
+    ) -> bytes:
+        if isinstance(value, str | pathlib.Path):
+            value = get_zim_illustration(
+                value, self.illustration_size, self.illustration_size
+            )
         value = self.get_binary_from(value)
         if not is_valid_image(
             image=value,
@@ -413,7 +425,10 @@ class IllustrationMetadata(IllustrationBasedMetadata):
     illustration_scale: int = 1
 
     def __init__(
-        self, value: bytes | io.IOBase | io.BytesIO, size: int, scale: int = 1
+        self,
+        value: bytes | io.IOBase | io.BytesIO | str | pathlib.Path,
+        size: int,
+        scale: int = 1,
     ) -> None:
         self.illustration_scale = scale
         self.illustration_size = size
@@ -423,8 +438,8 @@ def __init__(
 @mandatory
 class DefaultIllustrationMetadata(IllustrationBasedMetadata):
     meta_name = "Illustration_48x48@1"
-    illustration_size: int = 48
-    illustration_scale: int = 1
+    illustration_size: int = DEFAULT_ZIM_ILLLUSTRATION_SIZE
+    illustration_scale: int = DEFAULT_ZIM_ILLLUSTRATION_SCALE
 
 
 @mandatory

tests/image/test_illustration.py

@@ -0,0 +1,69 @@
+from pathlib import Path
+
+import pytest
+from PIL.Image import open as pilopen
+
+from zimscraperlib.image.illustration import get_zim_illustration
+
+COMMONS_IMAGE_PATH = (Path(__file__) / "../../files/commons.png").resolve()
+COMMONS_48_IMAGE_PATH = (Path(__file__) / "../../files/commons48.png").resolve()
+NINJA_IMAGE_PATH = (Path(__file__) / "../../files/ninja.webp").resolve()
+
+
+@pytest.mark.parametrize(
+    "user_illustration, expected_max_filesize",
+    [
+        pytest.param(COMMONS_IMAGE_PATH, 5000, id="big_commons"),
+        pytest.param(COMMONS_48_IMAGE_PATH, 4000, id="small_commons"),
+        pytest.param(NINJA_IMAGE_PATH, 5000, id="ninja"),
+        pytest.param(
+            "https://upload.wikimedia.org/wikipedia/commons/thumb/4/4a/Commons-logo.svg/250px-Commons-logo.svg.png",
+            4000,
+            id="png_url",
+        ),
+        pytest.param(
+            "https://upload.wikimedia.org/wikipedia/commons/4/4a/Commons-logo.svg",
+            4000,
+            id="svg_url",
+        ),
+    ],
+)
+def test_get_zim_illustration(
+    user_illustration: str | Path,
+    expected_max_filesize: int,
+):
+    image = get_zim_illustration(user_illustration)
+    assert len(image.getvalue()) < expected_max_filesize
+    with pilopen(image) as image_details:
+        assert image_details.format == "PNG"
+        assert image_details.size == (48, 48)
+
+
+def test_get_missing_user_zim_illustration():
+    with pytest.raises(Exception, match="missing.png could not be found"):
+        get_zim_illustration("./missing.png")
+
+
+def test_get_missing_default_zim_illustration():
+    with pytest.raises(Exception, match="Illustration is missing"):
+        get_zim_illustration("")
+
+
+def test_get_zim_illustration_custom_size():
+    image = get_zim_illustration(NINJA_IMAGE_PATH, 96, 120)
+    assert len(image.getvalue()) < 21000
+    with pilopen(image) as image_details:
+        assert image_details.format == "PNG"
+        assert image_details.size == (96, 120)
+
+
+def test_get_zim_illustration_method():
+    image_cover = get_zim_illustration(NINJA_IMAGE_PATH, resize_method="cover")
+    image_contain = get_zim_illustration(NINJA_IMAGE_PATH, resize_method="contain")
+    # cover image is always bigger than contain image size more pixels are
+    # "used/non-transparent"
+    assert len(image_cover.getvalue()) > len(image_contain.getvalue())
+    for image in [image_cover, image_contain]:
+        with pilopen(image) as image_details:
+            assert image_details.format == "PNG"
+            assert image_details.size == (48, 48)

tests/zim/test_metadata.py

@@ -10,6 +10,7 @@
 
 import pytest
 from beartype.roar import BeartypeCallHintParamViolation as InvalidType
+from PIL.Image import open as pilopen
 
 from zimscraperlib.zim import metadata
 
@@ -213,6 +214,11 @@ def test_validate_illustration_invalid_image():
         metadata.IllustrationMetadata(b"PN", size=48)
 
 
+def test_validate_illustration_invalid_image_location():
+    with pytest.raises(OSError, match="missing.png could not be found"):
+        metadata.IllustrationMetadata("missing.png", size=48)
+
+
 def test_validate_illustration_wrong_sizes(png_image2: pathlib.Path):
     with open(png_image2, "rb") as fh:
         png_data = fh.read()
@@ -222,6 +228,22 @@ def test_validate_illustration_wrong_sizes(png_image2: pathlib.Path):
         metadata.IllustrationMetadata(png_data, size=48)
 
 
+def test_validate_illustration_path_resized(png_image2: pathlib.Path):
+    with pilopen(
+        io.BytesIO(metadata.IllustrationMetadata(png_image2, size=32).libzim_value)
+    ) as image:
+        assert image.size == (32, 32)
+
+
+def test_validate_illustration_str_resized(png_image2: pathlib.Path):
+    with pilopen(
+        io.BytesIO(
+            metadata.IllustrationMetadata(png_image2.resolve(), size=48).libzim_value
+        )
+    ) as image:
+        assert image.size == (48, 48)
+
+
 def test_blank_metadata():
     with pytest.raises(ValueError, match=r"Missing value \(empty not allowed\)"):
         metadata.Metadata(name="Blank", value=b"")

tests/zim/test_zim_creator.py

@@ -14,6 +14,7 @@
 
 import pytest
 from libzim.writer import Compression  # pyright: ignore[reportMissingModuleSource]
+from PIL.Image import open as pilopen
 
 from zimscraperlib.constants import UTF8
 from zimscraperlib.download import save_large_file, stream_file
@@ -756,11 +757,9 @@ def test_relax_metadata(
     ],
 )
 def test_config_metadata(
-    tmp_path: pathlib.Path, png_image: pathlib.Path, tags: str | list[str]
+    tmp_path: pathlib.Path, png_image2: pathlib.Path, tags: str | list[str]
 ):
     fpath = tmp_path / "test_config.zim"
-    with open(png_image, "rb") as fh:
-        png_data = fh.read()
     creator = Creator(fpath, "").config_metadata(
         StandardMetadataList(
             Name=NameMetadata("wikipedia_fr_football"),
@@ -781,7 +780,7 @@ def test_config_metadata(
             Flavour=FlavourMetadata("nopic"),
             Source=SourceMetadata("https://en.wikipedia.org/"),
             Scraper=ScraperMetadata("mwoffliner 1.2.3"),
-            Illustration_48x48_at_1=DefaultIllustrationMetadata(png_data),
+            Illustration_48x48_at_1=DefaultIllustrationMetadata(png_image2),
         ),
         [CustomTextMetadata("X-TestMetadata", "Test Metadata")],
     )
@@ -817,7 +816,11 @@ def test_config_metadata(
     assert reader.get_text_metadata("Flavour") == "nopic"
     assert reader.get_text_metadata("Source") == "https://en.wikipedia.org/"
     assert reader.get_text_metadata("Scraper") == "mwoffliner 1.2.3"
-    assert reader.get_metadata("Illustration_48x48@1") == png_data
+    with pilopen(
+        io.BytesIO(reader.get_metadata("Illustration_48x48@1"))
+    ) as illustration:
+        assert illustration.size == (48, 48)
+        assert illustration.format == "PNG"
     assert reader.get_text_metadata("X-TestMetadata") == "Test Metadata"