For column icons and grid view emblems, support icons for both light and dark themes.

src/calibre/gui2/library/alternate_views.py

@@ -60,7 +60,7 @@ from qt.core import (
 from calibre import fit_image, human_readable, prepare_string_for_xml
 from calibre.constants import DEBUG, config_dir, islinux
 from calibre.ebooks.metadata import fmt_sidx, rating_to_stars
-from calibre.gui2 import clip_border_radius, config, empty_index, gprefs, rating_font
+from calibre.gui2 import clip_border_radius, config, empty_index, gprefs, rating_font, is_dark_theme
 from calibre.gui2.dnd import path_from_qurl
 from calibre.gui2.gestures import GestureManager
 from calibre.gui2.library.caches import CoverCache, ThumbnailCache
@@ -554,6 +554,13 @@ class CoverDelegate(QStyledItemDelegate):
         elif name == ':ondevice':
             ans = QIcon.ic('ok.png').pixmap(sz, sz)
         elif name:
+            pmap = None
+            if is_dark_theme():
+                n,ext = os.path.splitext(name)
+                d = os.path.join(config_dir, 'cc_icons', n + '-dark' + ext)
+                if os.path.exists(d):
+                    pmap = QIcon(d).pixmap(sz, sz)
+            if pmap is None:
                 pmap = QIcon(os.path.join(config_dir, 'cc_icons', name)).pixmap(sz, sz)
             if not pmap.isNull():
                 ans = pmap

src/calibre/gui2/library/models.py

@@ -23,7 +23,7 @@ from calibre.db.search import CONTAINS_MATCH, EQUALS_MATCH, REGEXP_MATCH, _match
 from calibre.db.utils import force_to_bool
 from calibre.ebooks.metadata import authors_to_string, fmt_sidx, string_to_authors
 from calibre.ebooks.metadata.book.formatter import SafeFormat
-from calibre.gui2 import error_dialog, simple_excepthook
+from calibre.gui2 import error_dialog, simple_excepthook, is_dark_theme
 from calibre.gui2.library import DEFAULT_SORT
 from calibre.library.coloring import color_row_key
 from calibre.library.save_to_disk import find_plugboard
@@ -132,8 +132,15 @@ class ColumnIcon:  # {{{
                 total_width = 0
                 rh = max(2, self.model.row_height - 4)
                 dim = int(self.dpr * rh)
+                icon_dir = os.path.join(config_dir, 'cc_icons')
                 for icon in icons:
-                    d = os.path.join(config_dir, 'cc_icons', icon)
+                    d = None
+                    if is_dark_theme():
+                        root,ext = os.path.splitext(icon)
+                        d = os.path.join(icon_dir, root + '-dark' + ext)
+                        d = d if os.path.exists(d) else None
+                    if d is None:
+                        d = os.path.join(icon_dir, icon)
                     if (os.path.exists(d)):
                         bm = QPixmap(d)
                         scaled, nw, nh = fit_image(bm.width(), bm.height(), bm.width(), dim)

src/calibre/gui2/preferences/coloring.py

@@ -21,6 +21,7 @@ from qt.core import (
     QDoubleValidator,
     QFrame,
     QGridLayout,
+    QHBoxLayout,
     QIcon,
     QIntValidator,
     QItemSelection,
@@ -47,7 +48,8 @@ from qt.core import (
 
 from calibre import as_unicode, prepare_string_for_xml, sanitize_file_name
 from calibre.constants import config_dir
-from calibre.gui2 import choose_files, choose_save_file, error_dialog, gprefs, open_local_file, pixmap_to_data, question_dialog
+from calibre.gui2 import (choose_files, choose_save_file, error_dialog, gprefs, info_dialog,
+                          open_local_file, pixmap_to_data, question_dialog)
 from calibre.gui2.dialogs.template_dialog import TemplateDialog
 from calibre.gui2.metadata.single_download import RichTextDelegate
 from calibre.gui2.preferences import ListViewWithMoveByKeyPress
@@ -512,11 +514,19 @@ class RuleEditor(QDialog):  # {{{
             ' blanking all of its boxes'))
         l.addWidget(l6, 8, 0, 1, 8)
 
+        bbl = QHBoxLayout()
         self.bb = bb = QDialogButtonBox(
                 QDialogButtonBox.StandardButton.Ok|QDialogButtonBox.StandardButton.Cancel)
         bb.accepted.connect(self.accept)
         bb.rejected.connect(self.reject)
-        l.addWidget(bb, 9, 0, 1, 8)
+        if self.rule_kind in ('emblem', 'icon'):
+            theme_button = QPushButton(_('Using icons in light/dark themes'))
+            theme_button.setIcon(QIcon.ic('help.png'))
+            theme_button.clicked.connect(self.show_theme_help)
+            bbl.addWidget(theme_button)
+        bbl.addStretch(10)
+        bbl.addWidget(bb)
+        l.addLayout(bbl, 9, 0, 1, 8)
         if self.rule_kind != 'color':
             self.remove_button = b = bb.addButton(_('&Remove icons'), QDialogButtonBox.ButtonRole.ActionRole)
             b.setIcon(QIcon.ic('minus.png'))
@@ -555,6 +565,23 @@ class RuleEditor(QDialog):  # {{{
 
         self.resize(self.sizeHint())
 
+    def show_theme_help(self):
+        msg = '<p>'+ _(
+            'You can use different icons in light and dark themes. To do this, '
+            'add two icons to the icon list. The light theme icon will have '
+            'the "normal" name, for example "ok.png". The dark theme icon must '
+            'have the same name with "-dark" appended. For example, if the light '
+            'theme icon is named "ok.png" then the dark theme icon must be named '
+            '"ok-dark.png".'
+            '</p><p>'
+            'When defining a rule, always use the "normal" name. The -dark icon will be '
+            'automatically substituted for the normal icon when a dark theme is '
+            'being used.'
+            '</p><p>'
+            'Remember to add both the light and dark theme icons to the list of icons.'
+        ) + '</p>'
+        info_dialog(self, _('Using icons in light/dark themes'), msg, show=True)
+
     def multiple_box_clicked(self):
         self.update_filename_box()
         self.update_icon_filenames_in_box()