[WIP] PNG convert/pngcrush extension

nemo_convert_png.py

@@ -0,0 +1,190 @@
+'''Extension for Nemo's context menu to easily convert images to PNG and
+optimize their filesize with pngcrush.'''
+from __future__ import annotations
+
+import os
+import subprocess
+from urllib.parse import unquote_plus, urlparse
+
+from PIL import Image, UnidentifiedImageError
+import PySimpleGUI as sg
+
+import gi
+gi.require_version('Nemo', '3.0')
+from gi.repository import GObject, Nemo  # type: ignore pylint: disable=wrong-import-position
+
+
+EXTENSIONS = ('jpg', 'jpeg', 'gif', 'tiff', 'bmp', 'png')
+uqp= unquote_plus
+
+def get_files(files_in: list[GObject]) -> list[str]|None:
+    """
+    Retrieve filenames as cross-platform safe strings from file objects.
+
+    :param files_in: List of file objects.
+    """
+    files = []
+    for file_in in files_in:
+        file_in = unquote_plus(file_in.get_uri()[7:])
+        if os.path.isfile(file_in):
+            files.append(file_in)
+    if files:
+        return files
+    return None
+
+def convert_one(file: str) -> None:
+    '''
+    Converts an image to a PNG.
+
+    :param file: Filename of the image to convert.
+    '''
+    filename = f'{file.split(".")[-2]}.png'
+    try:
+        img = Image.open(file).convert('RGB')
+    except UnidentifiedImageError:
+        img = False
+    if img:
+        os.remove(file)
+        img.save(filename, 'PNG')
+
+
+def convert_images(_, files: list[str]) -> list[str]:
+    '''
+    Called by the context menu item "Convert selected image(s) to PNG".
+
+    :param files: The currently selected files.
+    '''
+
+    filenames = [f'{file.split(".")[-2]}.png' for file in files]
+    count = sum(not file.endswith('png') for file in files)
+    for i, file in enumerate(files):
+        if not file.endswith('png'):
+            sg.OneLineProgressMeter('Please wait...', i+1, count, 'pb', 'Converting images', orientation='h')
+            convert_one(file)
+    sg.OneLineProgressMeter('', count, count, key='pb')
+    return filenames
+
+
+def crush_one(file: str) -> None:
+    '''
+    Runs pngcrush on a png file.
+
+    :param file: The file to execute this action on.
+    '''
+    subprocess.run(['pngcrush', '-rem', 'alla', '-nofilecheck', '-fix', '-ow',
+                    '-reduce', '-m', '0', file], check=False)
+
+
+def crush_images(_, files: list[str]) -> None:
+    '''
+    Called by the context menu item "Optimize image(s) with pngcrush.
+
+    :param files: The currently selected files.
+    '''
+    for i, file in enumerate(files):
+        sg.OneLineProgressMeter('Please wait...', i+1, len(files), 'pb',
+                                'Optimize images with pngcrush', orientation='h')
+        crush_one(file)
+    sg.OneLineProgressMeter('', len(files), len(files), key='pb')
+
+
+
+def convert_and_crush(_, files: list[str]) -> None:
+    '''
+    Called by the context menu item "Convert to PNG and optimize.
+
+    :param files: The currently selected files.
+    '''
+    converted = convert_images(None, files)
+    crush_images(None, converted)
+
+
+class PNGConverter(GObject.GObject, Nemo.MenuProvider):
+    '''Class for extension context menu items.'''
+
+    def __init__(self):
+        '''File manager crashes if init is not called.'''
+        ...
+
+    def get_background_items( # pylint: disable=arguments-differ
+        self, _, folder: GObject) -> list[Nemo.MenuItem]|None:
+        '''
+        Called when context menu is called with no file objects selected.
+
+        :param folder: Nemo's current working directory.
+        '''
+
+        folder = urlparse(folder.get_uri()).path
+        files = [uqp(os.path.join(folder, f))
+                 for f in os.listdir(uqp(folder))
+                 if os.path.isfile(uqp(os.path.join(folder, f))) and
+                 f.lower().endswith(EXTENSIONS)]
+
+        if all(file.endswith('png') for file in files):
+            crush = Nemo.MenuItem(
+                name='CrushImages',
+                label='Optimize image(s) with pngcrush',
+                tip='Optimize image filesizes with pngcrush'
+            )
+            crush.connect('activate', crush_images, files)
+            return [crush]
+
+        if any(file.endswith(EXTENSIONS) for file in files):
+            convert = Nemo.MenuItem(
+                name="ConvertAllImagestoPNG",
+                label="Convert all images to PNG",
+                tip="Convert all images to PNG"
+            )
+            convert.connect('activate', convert_images, files)
+
+            crush = Nemo.MenuItem(
+                name='ConvertandCrush',
+                label="Convert images to PNG and optimize",
+                tip="Convert images to PNG and optimize filesizes with pngcrush"
+            )
+            crush.connect('activate', convert_and_crush, files)
+            return [convert, crush]
+
+
+
+    def get_file_items( # pylint: disable=arguments-differ
+        self, _, files: list[GObject]) -> list[Nemo.MenuItem]|None:
+        '''
+        Called when context menu is called with files selected.
+
+        :param files: The currently selected file objects.
+        '''
+        files = get_files(files) # type: ignore
+        try:
+            is_iter = iter(files)
+            check = all(file.lower().endswith('png') for file in files)
+        except TypeError:
+            is_iter = False
+            check = False
+        if check:
+            convert = Nemo.MenuItem(
+                name="CrushImages",
+                label="Optimize image(s) with pngcrush",
+                tip="Optimize filesize(s) with pngcrush"
+            )
+            convert.connect('activate', crush_images, files)
+            return [convert]
+
+        if is_iter:
+            check = all(file.lower().endswith(EXTENSIONS) for file in files)
+        if check:
+            convert = Nemo.MenuItem(
+                name="ConvertImagetoPNG",
+                label="Convert selected image(s) to .png",
+                tip="Convert image(s) to .png"
+            )
+            convert.connect('activate', convert_images, files)
+
+            crush = Nemo.MenuItem(
+                name="ConvertandCrush",
+                label="Convert to PNG and optimize with pngcrush",
+                tip="Convert image(s) to PNG and optimize filesize(s) with\
+                    pngcrush"
+            )
+            crush.connect('activate', convert_and_crush, files)
+            return [convert, crush]