[capink]

Note: This action is now available as part of the builtin Single Field Edit Action.

from functools import partial

from qt.core import (QApplication, Qt)

from calibre.gui2 import error_dialog

from calibre_plugins.action_chains.common_utils import DoubleProgressDialog
from calibre_plugins.action_chains.actions.base import ChainAction

class TrimCover(ChainAction):

    name = 'Trim Cover'
    support_scopes = True

    def trim_covers(self, db, book_ids, pbar):

        from calibre.utils.img import (
            image_from_data, image_to_data, remove_borders_from_image
        )
        
        pbar.update_overall(len(book_ids))
        
        for book_id in book_ids:
            cdata = db.new_api.cover(book_id)
            if cdata:
                img = image_from_data(cdata)
                nimg = remove_borders_from_image(img)
                if nimg is not img:
                    cdata = image_to_data(nimg)
                    db.new_api.set_cover({book_id:cdata})
            msg = _('Trimming cover for book_id: {}'.format(book_id))
            pbar.update_progress(1, msg)

    def run(self, gui, settings, chain):
        db = gui.current_db
        book_ids = chain.scope().get_book_ids()

        callback = partial(self.trim_covers, db, book_ids)
        pd = DoubleProgressDialog(1, callback, gui, window_title=_('Trimming ...'))

        gui.tags_view.blockSignals(True)
        QApplication.setOverrideCursor(Qt.ArrowCursor)
        try:
            pd.exec_()

            pd.thread = None

            if pd.error is not None:
                return error_dialog(gui, _('Failed'),
                        pd.error[0], det_msg=pd.error[1],
                        show=True)
        finally:
            QApplication.restoreOverrideCursor()
            gui.tags_view.recount()