From 5346902c6f3fe04d32a7b8cf252c57ab695886d3 Mon Sep 17 00:00:00 2001
From: Kovid Goyal <kovid@kovidgoyal.net>
Date: Mon, 23 Apr 2018 18:19:53 +0530
Subject: [PATCH] Use a progress spinner in the PDF covers dialog

---
 src/calibre/gui2/metadata/pdf_covers.py       | 17 ++++------
 .../gui2/progress_indicator/__init__.py       | 32 ++++++++++++++++++-
 2 files changed, 38 insertions(+), 11 deletions(-)

diff --git a/src/calibre/gui2/metadata/pdf_covers.py b/src/calibre/gui2/metadata/pdf_covers.py
index c6d9b0eb26..376dd297d9 100644
--- a/src/calibre/gui2/metadata/pdf_covers.py
+++ b/src/calibre/gui2/metadata/pdf_covers.py
@@ -13,14 +13,15 @@ from glob import glob
 
 import sip
 from PyQt5.Qt import (
-    QDialog, QApplication, QLabel, QStackedLayout, QVBoxLayout, QDialogButtonBox, Qt,
-    pyqtSignal, QListWidget, QListWidgetItem, QSize, QPixmap, QStyledItemDelegate, QWidget
+    QDialog, QApplication, QLabel, QVBoxLayout, QDialogButtonBox, Qt,
+    pyqtSignal, QListWidget, QListWidgetItem, QSize, QPixmap, QStyledItemDelegate
 )
 
 from calibre import as_unicode
 from calibre.ebooks.metadata.pdf import page_images
 from calibre.gui2 import error_dialog, file_icon_provider
 from calibre.ptempfile import PersistentTemporaryDirectory
+from calibre.gui2.progress_indicator import WaitLayout
 
 
 class CoverDelegate(QStyledItemDelegate):
@@ -44,14 +45,10 @@ class PDFCovers(QDialog):
     def __init__(self, pdfpath, parent=None):
         QDialog.__init__(self, parent)
         self.pdfpath = pdfpath
-        self.stack = QStackedLayout(self)
-        self.loading = QLabel('<b>'+_('Rendering PDF pages, please wait...'))
-        self.stack.addWidget(self.loading)
+        self.stack = WaitLayout(_('Rendering PDF pages, please wait...'), parent=self)
+        self.container = self.stack.after
 
-        self.container = QWidget(self)
-        self.stack.addWidget(self.container)
         self.container.l = l = QVBoxLayout(self.container)
-
         self.la = la = QLabel(_('Choose a cover from the list of PDF pages below'))
         l.addWidget(la)
         self.covers = c = QListWidget(self)
@@ -113,7 +110,7 @@ class PDFCovers(QDialog):
             self.rendering_done.emit()
 
     def hide_pages(self):
-        self.stack.setCurrentIndex(0)
+        self.stack.start()
         self.more_pages.setVisible(False)
 
     def show_pages(self):
@@ -122,7 +119,7 @@ class PDFCovers(QDialog):
                 _('Could not render this PDF file'), show=True, det_msg=self.error)
             self.reject()
             return
-        self.stack.setCurrentIndex(1)
+        self.stack.stop()
         files = glob(os.path.join(self.current_tdir, '*.jpg')) + glob(os.path.join(self.current_tdir, '*.jpeg'))
         if not files and not self.covers.count():
             error_dialog(self, _('Failed to render'),
diff --git a/src/calibre/gui2/progress_indicator/__init__.py b/src/calibre/gui2/progress_indicator/__init__.py
index 3c1328fd3e..7444d1b158 100644
--- a/src/calibre/gui2/progress_indicator/__init__.py
+++ b/src/calibre/gui2/progress_indicator/__init__.py
@@ -7,7 +7,7 @@ from __future__ import (unicode_literals, division, absolute_import,
 
 from PyQt5.Qt import (
     Qt, QWidget, QSizePolicy, QSize, QRect, QConicalGradient, QPen, QBrush,
-    QPainter, QTimer, QVBoxLayout, QLabel, QStackedWidget, QDialog
+    QPainter, QTimer, QVBoxLayout, QLabel, QStackedWidget, QDialog, QStackedLayout
 )
 
 
@@ -113,6 +113,7 @@ class ProgressSpinner(QWidget):
                 traceback.print_exc()
                 self.errored_out = True
 
+
 ProgressIndicator = ProgressSpinner
 
 
@@ -167,6 +168,35 @@ class WaitStack(QStackedWidget):
     def msg(self, val):
         self.wp.msg = val
 
+
+class WaitLayout(QStackedLayout):
+
+    def __init__(self, msg, after=None, parent=None, size=256, interval=10):
+        QStackedLayout.__init__(self, parent)
+        self.wp = WaitPanel(msg, parent, size, interval)
+        if after is None:
+            after = QWidget(parent)
+        self.after = after
+        self.addWidget(self.wp)
+        self.addWidget(after)
+
+    def start(self):
+        self.setCurrentWidget(self.wp)
+        self.wp.start()
+
+    def stop(self):
+        self.wp.stop()
+        self.setCurrentWidget(self.after)
+
+    @property
+    def msg(self):
+        return self.wp.msg
+
+    @msg.setter
+    def msg(self, val):
+        self.wp.msg = val
+
+
 if __name__ == '__main__':
     from calibre.gui2 import Application
     app = Application([])