Implement new spinner for metadata download dialog

src/calibre/gui2/metadata/single_download.py

@@ -29,7 +29,7 @@ from calibre.ebooks.metadata.sources.identify import urls_from_identifiers
 from calibre.ebooks.metadata.book.base import Metadata
 from calibre.ebooks.metadata.opf2 import OPF
 from calibre.gui2 import error_dialog, rating_font, gprefs
-from calibre.gui2.progress_indicator import draw_snake_spinner
+from calibre.gui2.progress_indicator import SpinAnimator
 from calibre.gui2.widgets2 import HTMLDisplay
 from calibre.utils.date import (utcnow, fromordinal, format_date,
         UNDEFINED_DATE, as_utc)
@@ -88,33 +88,25 @@ class CoverDelegate(QStyledItemDelegate):  # {{{
 
     def __init__(self, parent):
         QStyledItemDelegate.__init__(self, parent)
-
+        self.animator = SpinAnimator(self)
-        self.angle = 0
+        self.animator.updated.connect(self.needs_redraw)
-        self.timer = QTimer(self)
+        self.color = parent.palette().color(QPalette.ColorRole.WindowText)
-        self.timer.timeout.connect(self.frame_changed)
-        self.dark_color = parent.palette().color(QPalette.ColorRole.WindowText)
-        self.light_color = parent.palette().color(QPalette.ColorRole.Window)
         self.spinner_width = 64
 
-    def frame_changed(self, *args):
-        self.angle = (self.angle-2)%360
-        self.needs_redraw.emit()
-
     def start_animation(self):
-        self.angle = 0
+        self.animator.start()
-        self.timer.start(10)
 
     def stop_animation(self):
-        self.timer.stop()
+        self.animator.stop()
 
     def paint(self, painter, option, index):
         QStyledItemDelegate.paint(self, painter, option, index)
         style = QApplication.style()
-        waiting = self.timer.isActive() and bool(index.data(Qt.ItemDataRole.UserRole))
+        waiting = self.animator.is_running() and bool(index.data(Qt.ItemDataRole.UserRole))
         if waiting:
             rect = QRect(0, 0, self.spinner_width, self.spinner_width)
             rect.moveCenter(option.rect.center())
-            draw_snake_spinner(painter, rect, self.angle, self.light_color, self.dark_color)
+            self.animator.draw(painter, rect, self.color)
         else:
             # Ensure the cover is rendered over any selection rect
             style.drawItemPixmap(painter, option.rect, Qt.AlignmentFlag.AlignTop|Qt.AlignmentFlag.AlignHCenter,

src/calibre/gui2/progress_indicator/QProgressIndicator.sip

@@ -19,7 +19,7 @@ class SpinAnimator : QObject {
 %End
 
 public:
-    SpinAnimator(QWidget *parent /TransferThis/ = 0, int speed_factor=300);
+    SpinAnimator(QObject *parent /TransferThis/ = 0, int speed_factor=300);
 	float get_arc_length() const ;
 	int get_arc_rotation() const ;
 	int get_overall_rotation() const ;

src/calibre/gui2/progress_indicator/__init__.py

@@ -3,8 +3,8 @@
 # License: GPLv3 Copyright: 2015, Kovid Goyal <kovid at kovidgoyal.net>
 
 from PyQt5.Qt import (
-    QDialog, QLabel, QSizePolicy, QStackedLayout, QStackedWidget, Qt, QVBoxLayout,
+    QDialog, QLabel, QObject, QSizePolicy, QStackedLayout, QStackedWidget, Qt,
-    QWidget
+    QVBoxLayout, QWidget, pyqtSignal
 )
 
 from calibre_extensions.progress_indicator import (
@@ -13,6 +13,30 @@ from calibre_extensions.progress_indicator import (
 
 draw_snake_spinner
 
+try:
+    from calibre_extensions.progress_indicator import SpinAnimator
+except ImportError:
+    # dummy class for people running from source without updated binaries
+    class SpinAnimator(QObject):
+
+        updated = pyqtSignal()
+
+        def __init__(self, parent):
+            QObject.__init__(self, parent)
+            self.running = False
+
+        def draw(self, *a):
+            pass
+
+        def start(self):
+            self.running = True
+
+        def stop(self):
+            self.running = False
+
+        def is_running(self):
+            return self.running
+
 
 class WaitPanel(QWidget):
 
@@ -95,7 +119,8 @@ class WaitLayout(QStackedLayout):
 
 
 def develop():
-    from PyQt5.Qt import QPalette, QPainter
+    from PyQt5.Qt import QPainter, QPalette
+
     from calibre.gui2 import Application
     from calibre_extensions.progress_indicator import SpinAnimator