qt: Port Windows taskbar progress to native Windows API

Author: kwsantiago

src/qt/CMakeLists.txt

@@ -257,6 +257,8 @@ add_library(bitcoinqt STATIC EXCLUDE_FROM_ALL
   utilitydialog.h
   $<$<PLATFORM_ID:Windows>:winshutdownmonitor.cpp>
   $<$<PLATFORM_ID:Windows>:winshutdownmonitor.h>
+  $<$<PLATFORM_ID:Windows>:wintaskbarprogress.cpp>
+  $<$<PLATFORM_ID:Windows>:wintaskbarprogress.h>
   bitcoin.qrc
   ${CMAKE_CURRENT_BINARY_DIR}/bitcoin_locale.qrc
   ${CMAKE_CURRENT_BINARY_DIR}/bitcoin_rendered.qrc

src/qt/bitcoingui.cpp

@@ -35,8 +35,7 @@
 #include <qt/macdockiconhandler.h>
 #endif
 #ifdef BITCOIN_QT_WIN_TASKBAR
-#include <QWinTaskbarButton>
-#include <QWinTaskbarProgress>
+#include <qt/wintaskbarprogress.h>
 #endif
 
 #include <chain.h>
@@ -232,7 +231,10 @@ BitcoinGUI::BitcoinGUI(interfaces::Node& node, const PlatformStyle *_platformSty
     m_app_nap_inhibitor = new CAppNapInhibitor;
 #endif
 #ifdef BITCOIN_QT_WIN_TASKBAR
-    m_taskbar_button = new QWinTaskbarButton(this);
+    m_taskbar_progress = new WinTaskbarProgress();
+    if (windowHandle()) {
+        m_taskbar_progress->setWindow(windowHandle());
+    }
 #endif
 
     GUIUtil::handleCloseWindowShortcut(this);
@@ -252,7 +254,7 @@ BitcoinGUI::~BitcoinGUI()
     MacDockIconHandler::cleanup();
 #endif
 #ifdef BITCOIN_QT_WIN_TASKBAR
-    delete m_taskbar_button;
+    delete m_taskbar_progress;
 #endif
 
     delete NetWatch;
@@ -1238,11 +1240,6 @@ void BitcoinGUI::setNumBlocks(int count, const QDateTime& blockDate, double nVer
 
     tooltip = tr("Processed %n block(s) of transaction history.", "", count);
 
-#ifdef BITCOIN_QT_WIN_TASKBAR
-    m_taskbar_button->setWindow(windowHandle());
-    QWinTaskbarProgress* taskbar_progress = m_taskbar_button->progress();
-#endif
-
     // Set icon state: spinning if catching up, tick otherwise
     if (secs < MAX_BLOCK_TIME_GAP) {
         tooltip = tr("Up to date") + QString(".<br>") + tooltip;
@@ -1259,7 +1256,7 @@ void BitcoinGUI::setNumBlocks(int count, const QDateTime& blockDate, double nVer
         progressBarLabel->setVisible(false);
         progressBar->setVisible(false);
 #ifdef BITCOIN_QT_WIN_TASKBAR
-        taskbar_progress->setVisible(false);
+        m_taskbar_progress->setVisible(false);
 #endif
     }
     else
@@ -1276,8 +1273,8 @@ void BitcoinGUI::setNumBlocks(int count, const QDateTime& blockDate, double nVer
         progressBar->setValue(nVerificationProgress * 1000000000.0 + 0.5);
         progressBar->setVisible(true);
 #ifdef BITCOIN_QT_WIN_TASKBAR
-        taskbar_progress->setValue(qRound(nVerificationProgress * 100.0));
-        taskbar_progress->setVisible(true);
+        m_taskbar_progress->setValue(qRound(nVerificationProgress * 100.0));
+        m_taskbar_progress->setVisible(true);
 #endif
 
         tooltip = tr("Catching up…") + QString("<br>") + tooltip;
@@ -1448,6 +1445,13 @@ void BitcoinGUI::showEvent(QShowEvent *event)
     showMempoolStatsAction->setEnabled(true);
     aboutAction->setEnabled(true);
     optionsAction->setEnabled(true);
+
+#ifdef BITCOIN_QT_WIN_TASKBAR
+    // If window handle wasn't available during construction, set it now
+    if (m_taskbar_progress && !m_taskbar_progress->window() && windowHandle()) {
+        m_taskbar_progress->setWindow(windowHandle());
+    }
+#endif
 }
 
 #ifdef ENABLE_WALLET

src/qt/bitcoingui.h

@@ -55,9 +55,10 @@ class QComboBox;
 class QDateTime;
 class QProgressBar;
 class QProgressDialog;
-class QWinTaskbarButton;
 QT_END_NAMESPACE
 
+class WinTaskbarProgress;
+
 namespace GUIUtil {
 class ClickableLabel;
 class ClickableProgressBar;
@@ -180,7 +181,7 @@ class BitcoinGUI : public QMainWindow
     RPCConsole* rpcConsole = nullptr;
     HelpMessageDialog* helpMessageDialog = nullptr;
 #ifdef BITCOIN_QT_WIN_TASKBAR
-    QWinTaskbarButton* m_taskbar_button = nullptr;
+    WinTaskbarProgress* m_taskbar_progress = nullptr;
 #endif
     ModalOverlay* modalOverlay = nullptr;
     MempoolStats* mempoolStats = nullptr;

src/qt/wintaskbarprogress.cpp

@@ -0,0 +1,110 @@
+// Copyright (c) 2025 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#include <qt/wintaskbarprogress.h>
+
+#include <QWindow>
+
+#include <windows.h>
+#include <shobjidl.h>
+
+#pragma comment(lib, "ole32.lib")
+#pragma comment(lib, "shell32.lib")
+
+WinTaskbarProgress::WinTaskbarProgress(QObject *parent)
+    : QObject(parent)
+{
+}
+
+WinTaskbarProgress::~WinTaskbarProgress()
+{
+    releaseTaskbarButton();
+}
+
+void WinTaskbarProgress::setWindow(QWindow* window)
+{
+    if (m_window == window) {
+        return;
+    }
+
+    m_window = window;
+    initTaskbarButton();
+    updateProgress();
+}
+
+QWindow* WinTaskbarProgress::window() const
+{
+    return m_window;
+}
+
+void WinTaskbarProgress::setValue(int value)
+{
+    if (m_value == value) {
+        return;
+    }
+
+    m_value = value;
+    updateProgress();
+}
+
+void WinTaskbarProgress::setVisible(bool visible)
+{
+    if (m_visible == visible) {
+        return;
+    }
+
+    m_visible = visible;
+    updateProgress();
+}
+
+void WinTaskbarProgress::updateProgress()
+{
+    if (!m_taskbar_button || !m_window) {
+        return;
+    }
+
+    ITaskbarList3* pTaskbarList = (ITaskbarList3*)m_taskbar_button;
+
+    if (m_visible) {
+        // Set progress value
+        pTaskbarList->SetProgressValue((HWND)m_window->winId(), m_value, 100);
+        // Set progress state to normal
+        pTaskbarList->SetProgressState((HWND)m_window->winId(), TBPF_NORMAL);
+    } else {
+        // Hide progress bar
+        pTaskbarList->SetProgressState((HWND)m_window->winId(), TBPF_NOPROGRESS);
+    }
+}
+
+void WinTaskbarProgress::initTaskbarButton()
+{
+    if (m_taskbar_button || !m_window) {
+        return;
+    }
+
+    ITaskbarList3* pTaskbarList = nullptr;
+    HRESULT hr = CoCreateInstance(CLSID_TaskbarList, nullptr, CLSCTX_INPROC_SERVER,
+                                  IID_PPV_ARGS(&pTaskbarList));
+
+    if (SUCCEEDED(hr)) {
+        hr = pTaskbarList->HrInit();
+        if (SUCCEEDED(hr)) {
+            m_taskbar_button = pTaskbarList;
+        } else {
+            pTaskbarList->Release();
+        }
+    }
+}
+
+void WinTaskbarProgress::releaseTaskbarButton()
+{
+    if (!m_taskbar_button) {
+        return;
+    }
+
+    ITaskbarList3* pTaskbarList = (ITaskbarList3*)m_taskbar_button;
+    pTaskbarList->SetProgressState((HWND)m_window->winId(), TBPF_NOPROGRESS);
+    pTaskbarList->Release();
+    m_taskbar_button = nullptr;
+}

src/qt/wintaskbarprogress.h

@@ -0,0 +1,60 @@
+// Copyright (c) 2025 The Bitcoin Core developers
+// Distributed under the MIT software license, see the accompanying
+// file COPYING or http://www.opensource.org/licenses/mit-license.php.
+
+#ifndef BITCOIN_QT_WINTASKBARPROGRESS_H
+#define BITCOIN_QT_WINTASKBARPROGRESS_H
+
+#include <QObject>
+
+class QWindow;
+
+/**
+ * Manages Windows taskbar button progress indicator.
+ * Provides a platform-independent wrapper around the native Windows API
+ * for taskbar progress updates.
+ */
+class WinTaskbarProgress : public QObject
+{
+    Q_OBJECT
+
+public:
+    explicit WinTaskbarProgress(QObject *parent = nullptr);
+    ~WinTaskbarProgress();
+
+    /**
+     * Set the window handle for taskbar progress updates
+     * @param[in] window The QWindow to update taskbar progress for
+     */
+    void setWindow(QWindow* window);
+
+    /**
+     * Get the current window handle
+     * @return The current QWindow pointer, or nullptr if not set
+     */
+    QWindow* window() const;
+
+    /**
+     * Set the progress value
+     * @param[in] value Progress value (0-100)
+     */
+    void setValue(int value);
+
+    /**
+     * Set progress visibility
+     * @param[in] visible True to show progress, false to hide
+     */
+    void setVisible(bool visible);
+
+private:
+    QWindow* m_window = nullptr;
+    int m_value = 0;
+    bool m_visible = false;
+    void* m_taskbar_button = nullptr; // ITaskbarList3*
+
+    void updateProgress();
+    void initTaskbarButton();
+    void releaseTaskbarButton();
+};
+
+#endif // BITCOIN_QT_WINTASKBARPROGRESS_H