Fix #1952034 [[Enhancement] Add a download icon to the Download metadata button in the Edit metadata window](https://bugs.launchpad.net/calibre/+bug/1952034)

src/calibre/gui2/metadata/single.py

@@ -11,10 +11,10 @@ import os
 from datetime import datetime
 from functools import partial
 from qt.core import (
-    QApplication, QDialog, QDialogButtonBox, QFont, QFrame,
+    QApplication, QDialog, QDialogButtonBox, QFont, QFrame, QGridLayout, QGroupBox,
-    QGridLayout, QGroupBox, QHBoxLayout, QIcon, QInputDialog, QKeySequence, QMenu,
+    QHBoxLayout, QIcon, QInputDialog, QKeySequence, QMenu, QPushButton, QScrollArea,
-    QPushButton, QScrollArea, QShortcut, QSize, QSizePolicy, QSpacerItem, QSplitter,
+    QShortcut, QSize, QSizePolicy, QSpacerItem, QSplitter, Qt, QTabWidget,
-    Qt, QTabWidget, QToolButton, QVBoxLayout, QWidget, pyqtSignal
+    QToolButton, QVBoxLayout, QWidget, pyqtSignal
 )
 
 from calibre.constants import ismacos
@@ -30,6 +30,7 @@ from calibre.gui2.metadata.basic_widgets import (
     TitleSortEdit, show_locked_file_error
 )
 from calibre.gui2.metadata.single_download import FullFetch
+from calibre.gui2.widgets2 import CenteredToolButton
 from calibre.library.comments import merge_comments as merge_two_comments
 from calibre.utils.config import tweaks
 from calibre.utils.date import local_tz
@@ -269,26 +270,14 @@ class MetadataSingleDialogBase(QDialog):
         self.pubdate = PubdateEdit(self)
         self.basic_metadata_widgets.extend([self.timestamp, self.pubdate])
 
-        self.fetch_metadata_button = b = RightClickButton(self)
+        self.fetch_metadata_button = b = CenteredToolButton(QIcon(I('download-metadata.png')), _('&Download metadata'), self)
-        # The following rigmarole is needed so that Qt gives the button the
+        b.setPopupMode(QToolButton.ToolButtonPopupMode.DelayedPopup)
-        # same height as the other buttons in the dialog. There is no way to
-        # center the text in a QToolButton with an icon, so we can't just set an
-        # icon
-        b.setIcon(QIcon(I('download-metadata.png')))
-        b.setToolButtonStyle(Qt.ToolButtonStyle.ToolButtonTextBesideIcon)
-        b.setMinimumHeight(b.sizeHint().height())
-        b.setIcon(QIcon())
-        b.setText(_('&Download metadata')), b.setPopupMode(QToolButton.ToolButtonPopupMode.DelayedPopup)
         b.setToolTip(_('Download metadata for this book [%s]') % self.download_shortcut.key().toString(QKeySequence.SequenceFormat.NativeText))
-        b.setSizePolicy(QSizePolicy(QSizePolicy.Policy.Expanding, QSizePolicy.Policy.Fixed))
         self.fetch_metadata_button.clicked.connect(self.fetch_metadata)
         self.fetch_metadata_menu = m = QMenu(self.fetch_metadata_button)
         m.addAction(QIcon(I('edit-undo.png')), _('Undo last metadata download'), self.undo_fetch_metadata)
         self.fetch_metadata_button.setMenu(m)
         self.download_shortcut.activated.connect(self.fetch_metadata_button.click)
-        font = self.fmb_font = QFont()
-        font.setBold(True)
-        self.fetch_metadata_button.setFont(font)
 
         if self.use_toolbutton_for_config_metadata:
             self.config_metadata_button = QToolButton(self)

src/calibre/gui2/widgets2.py

@@ -10,7 +10,7 @@ from qt.core import (
     QFontInfo, QFontMetrics, QIcon, QKeySequence, QLabel, QLayout, QMenu, QMimeData,
     QPalette, QPixmap, QPoint, QPushButton, QRect, QScrollArea, QSize, QSizePolicy,
     QStyle, QStyledItemDelegate, Qt, QTabWidget, QTextBrowser, QToolButton, QTextCursor,
-    QUndoCommand, QUndoStack, QUrl, QWidget, pyqtSignal, QBrush, QPainter
+    QUndoCommand, QUndoStack, QUrl, QWidget, pyqtSignal, QBrush, QPainter, QProxyStyle
 )
 
 from calibre.ebooks.metadata import rating_to_stars
@@ -158,6 +158,59 @@ class RightClickButton(QToolButton):
         return QToolButton.mousePressEvent(self, ev)
 
 
+class CenteredToolButtonStyle(QProxyStyle):
+
+    def __init__(self, ctb):
+        super().__init__()
+        self.setParent(ctb)
+        self.draw_text_called = self.draw_pixmap_called = False
+
+    def drawItemText(self, painter, rect, flags, palette, enabled, text, text_role=QPalette.ColorRole.NoRole):
+        b = self.parent()
+        if text != b.text():
+            return super().drawItemText(painter, rect, flags, palette, enabled, text, QPalette.ColorRole.NoRole)
+        self.text_rect = rect
+        self.text_flags = flags | Qt.AlignmentFlag.AlignCenter
+        self.text_palette = palette
+        self.text_enabled = enabled
+        self.text_role = text_role
+        self.draw_text_called = True
+        self.draw_both(painter)
+
+    def drawItemPixmap(self, painter, rect, alignment, pixmap):
+        self.pixmap_rect = rect
+        self.pixmap = pixmap
+        self.draw_pixmap_called = True
+        self.draw_both(painter)
+
+    def draw_both(self, painter):
+        if not self.draw_pixmap_called or not self.draw_text_called:
+            return
+        self.draw_text_called = self.draw_pixmap_called = False
+        b = self.parent()
+        fm = QFontMetrics(b.font())
+        w = b.iconSize().width()
+        full_rect = QRect(self.pixmap_rect.topLeft(), self.text_rect.bottomRight())
+        space = self.text_rect.left() - self.pixmap_rect.right() + 1
+        super().drawItemText(painter, full_rect, self.text_flags, self.text_palette, self.text_enabled, b.text(), self.text_role)
+        text_rect = self.itemTextRect(fm, full_rect, self.text_flags, self.text_enabled, b.text())
+        left = max(0, text_rect.left() - w - space)
+        pixmap_rect = QRect(left, self.pixmap_rect.top(), text_rect.right() - space - left, self.pixmap_rect.height())
+        super().drawItemPixmap(painter, pixmap_rect, Qt.AlignmentFlag.AlignLeft | Qt.AlignmentFlag.AlignVCenter, self.pixmap)
+
+
+class CenteredToolButton(RightClickButton):
+
+    def __init__(self, icon, text, parent=None):
+        super().__init__(parent)
+        self.setText(text)
+        self.ps = CenteredToolButtonStyle(self)
+        self.setStyle(self.ps)
+        self.setIcon(icon)
+        self.setSizePolicy(QSizePolicy(QSizePolicy.Policy.Expanding, QSizePolicy.Policy.Fixed))
+        self.setToolButtonStyle(Qt.ToolButtonStyle.ToolButtonTextBesideIcon)
+
+
 class Dialog(QDialog):
 
     '''