Merge bitcoin-core/gui#366: Dark Mode fixes/portability

9d5bf6bf01af40a9684f1b1f06a8df4aaf36b8f3 GUI: Always call parent changeEvent handler (Luke Dashjr)
c901d4d8ce7949276da57eacb82b1a3ce40cac27 GUI: Enable palette change adaptation on all platforms (Luke Dashjr)

Pull request description:

  The changes to support macOS "Dark Mode" are valid for any platform, and should work so long as Qt implements the PaletteChange event. (Worst case, we're no worse off with trying.)

  Additionally, we shouldn't block the parent classes from implementing event handlers. Who knows what side effects that could have.

ACKs for top commit:
  hebasto:
    ACK 9d5bf6bf01af40a9684f1b1f06a8df4aaf36b8f3, tested on Linux Mint 20.1 (Qt 5.12.8) with the [`qt5ct`](https://packages.ubuntu.com/focal/qt5ct) package installed.
  kristapsk:
    ACK 9d5bf6bf01af40a9684f1b1f06a8df4aaf36b8f3. Tested on Gentoo Linux with Xfce4 and Qt 5.15.2, does not break anything on my computer.

Tree-SHA512: dce2fff0ff129eda208132390a37424ff9607539287dbdbfdfd659ed9c4ea0472541e987489a04fd935e391dc006a35bfc9cfa9bcff33602b7dbd29b81c51626

8 files changed, 15 insertions, 18 deletions

diff --git a/src/qt/bitcoingui.cpp b/src/qt/bitcoingui.cpp
index 3d632ec702..f8aeb01659 100644
--- a/src/qt/bitcoingui.cpp
+++ b/src/qt/bitcoingui.cpp
@@ -1173,14 +1173,12 @@ void BitcoinGUI::message(const QString& title, QString message, unsigned int sty
 
 void BitcoinGUI::changeEvent(QEvent *e)
 {
-#ifdef Q_OS_MACOS
     if (e->type() == QEvent::PaletteChange) {
         overviewAction->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/overview")));
         sendCoinsAction->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/send")));
         receiveCoinsAction->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/receiving_addresses")));
         historyAction->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/history")));
     }
-#endif
 
     QMainWindow::changeEvent(e);
 
@@ -1511,14 +1509,14 @@ void UnitDisplayStatusBarControl::mousePressEvent(QMouseEvent *event)
 
 void UnitDisplayStatusBarControl::changeEvent(QEvent* e)
 {
-#ifdef Q_OS_MACOS
     if (e->type() == QEvent::PaletteChange) {
         QString style = QString("QLabel { color : %1 }").arg(m_platform_style->SingleColor().name());
         if (style != styleSheet()) {
             setStyleSheet(style);
         }
     }
-#endif
+
+    QLabel::changeEvent(e);
 }
 
 /** Creates context menu, its actions, and wires up all the relevant signals for mouse events. */
diff --git a/src/qt/coincontroldialog.cpp b/src/qt/coincontroldialog.cpp
index 2360fa9b37..d2a9365890 100644
--- a/src/qt/coincontroldialog.cpp
+++ b/src/qt/coincontroldialog.cpp
@@ -564,11 +564,11 @@ void CoinControlDialog::updateLabels(CCoinControl& m_coin_control, WalletModel *
 
 void CoinControlDialog::changeEvent(QEvent* e)
 {
-#ifdef Q_OS_MACOS
     if (e->type() == QEvent::PaletteChange) {
         updateView();
     }
-#endif
+
+    QDialog::changeEvent(e);
 }
 
 void CoinControlDialog::updateView()
diff --git a/src/qt/guiutil.cpp b/src/qt/guiutil.cpp
index 393dca8ccd..ecdfce2f5a 100644
--- a/src/qt/guiutil.cpp
+++ b/src/qt/guiutil.cpp
@@ -809,11 +809,10 @@ void ThemedLabel::setThemedPixmap(const QString& image_filename, int width, int
 
 void ThemedLabel::changeEvent(QEvent* e)
 {
-#ifdef Q_OS_MACOS
     if (e->type() == QEvent::PaletteChange) {
         updateThemedPixmap();
     }
-#endif
+
     QLabel::changeEvent(e);
 }
 
diff --git a/src/qt/overviewpage.cpp b/src/qt/overviewpage.cpp
index 26e3dd0d60..1fd1ff3142 100644
--- a/src/qt/overviewpage.cpp
+++ b/src/qt/overviewpage.cpp
@@ -297,13 +297,13 @@ void OverviewPage::setWalletModel(WalletModel *model)
 
 void OverviewPage::changeEvent(QEvent* e)
 {
-#ifdef Q_OS_MACOS
     if (e->type() == QEvent::PaletteChange) {
         QIcon icon = m_platform_style->SingleColorIcon(QStringLiteral(":/icons/warning"));
         ui->labelTransactionsStatus->setIcon(icon);
         ui->labelWalletStatus->setIcon(icon);
     }
-#endif
+
+    QWidget::changeEvent(e);
 }
 
 void OverviewPage::updateDisplayUnit()
diff --git a/src/qt/rpcconsole.cpp b/src/qt/rpcconsole.cpp
index ff4bfb16f6..bc0afa03c9 100644
--- a/src/qt/rpcconsole.cpp
+++ b/src/qt/rpcconsole.cpp
@@ -882,7 +882,6 @@ void RPCConsole::keyPressEvent(QKeyEvent *event)
 
 void RPCConsole::changeEvent(QEvent* e)
 {
-#ifdef Q_OS_MACOS
     if (e->type() == QEvent::PaletteChange) {
         ui->clearButton->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/remove")));
         ui->fontBiggerButton->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/fontbigger")));
@@ -896,7 +895,8 @@ void RPCConsole::changeEvent(QEvent* e)
                 platformStyle->SingleColorImage(ICON_MAPPING[i].source).scaled(QSize(consoleFontSize * 2, consoleFontSize * 2), Qt::IgnoreAspectRatio, Qt::SmoothTransformation));
         }
     }
-#endif
+
+    QWidget::changeEvent(e);
 }
 
 void RPCConsole::message(int category, const QString &message, bool html)
diff --git a/src/qt/sendcoinsentry.cpp b/src/qt/sendcoinsentry.cpp
index f701bb9615..683c0441fa 100644
--- a/src/qt/sendcoinsentry.cpp
+++ b/src/qt/sendcoinsentry.cpp
@@ -238,7 +238,6 @@ void SendCoinsEntry::updateDisplayUnit()
 
 void SendCoinsEntry::changeEvent(QEvent* e)
 {
-#ifdef Q_OS_MACOS
     if (e->type() == QEvent::PaletteChange) {
         ui->addressBookButton->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/address-book")));
         ui->pasteButton->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/editpaste")));
@@ -246,7 +245,8 @@ void SendCoinsEntry::changeEvent(QEvent* e)
         ui->deleteButton_is->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/remove")));
         ui->deleteButton_s->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/remove")));
     }
-#endif
+
+    QStackedWidget::changeEvent(e);
 }
 
 bool SendCoinsEntry::updateLabel(const QString &address)
diff --git a/src/qt/signverifymessagedialog.cpp b/src/qt/signverifymessagedialog.cpp
index b982cc577d..33589f09bf 100644
--- a/src/qt/signverifymessagedialog.cpp
+++ b/src/qt/signverifymessagedialog.cpp
@@ -286,7 +286,6 @@ bool SignVerifyMessageDialog::eventFilter(QObject *object, QEvent *event)
 
 void SignVerifyMessageDialog::changeEvent(QEvent* e)
 {
-#ifdef Q_OS_MACOS
     if (e->type() == QEvent::PaletteChange) {
         ui->addressBookButton_SM->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/address-book")));
         ui->pasteButton_SM->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/editpaste")));
@@ -297,5 +296,6 @@ void SignVerifyMessageDialog::changeEvent(QEvent* e)
         ui->verifyMessageButton_VM->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/transaction_0")));
         ui->clearButton_VM->setIcon(platformStyle->SingleColorIcon(QStringLiteral(":/icons/remove")));
     }
-#endif
+
+    QDialog::changeEvent(e);
 }
diff --git a/src/qt/transactionview.cpp b/src/qt/transactionview.cpp
index 4b1a546c7c..83d17a32c0 100644
--- a/src/qt/transactionview.cpp
+++ b/src/qt/transactionview.cpp
@@ -245,7 +245,6 @@ void TransactionView::setModel(WalletModel *_model)
 
 void TransactionView::changeEvent(QEvent* e)
 {
-#ifdef Q_OS_MACOS
     if (e->type() == QEvent::PaletteChange) {
         watchOnlyWidget->setItemIcon(
             TransactionFilterProxy::WatchOnlyFilter_Yes,
@@ -254,7 +253,8 @@ void TransactionView::changeEvent(QEvent* e)
             TransactionFilterProxy::WatchOnlyFilter_No,
             m_platform_style->SingleColorIcon(QStringLiteral(":/icons/eye_minus")));
     }
-#endif
+
+    QWidget::changeEvent(e);
 }
 
 void TransactionView::chooseDate(int idx)