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
   ${CMAKE_CURRENT_BINARY_DIR}/bitcoin_rendered.qrc
@@ -366,8 +368,8 @@ endif()
 if(WITH_TASKBAR_PROGRESS)
   target_link_libraries(bitcoinqt
     PRIVATE
-      "Qt${WITH_QT_VERSION}::WinExtras"
-      $<$<PLATFORM_ID:Windows>:dwmapi>
+      # Using native Windows API (ITaskbarList3), requires ole32 for COM
+      $<$<PLATFORM_ID:Windows>:ole32>
   )
 endif()
 

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);
@@ -251,6 +253,9 @@ BitcoinGUI::~BitcoinGUI()
     delete m_app_nap_inhibitor;
     MacDockIconHandler::cleanup();
 #endif
+#ifdef BITCOIN_QT_WIN_TASKBAR
+    delete m_taskbar_progress;
+#endif
 
     delete NetWatch;
     delete rpcConsole;
@@ -1235,11 +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;
@@ -1256,7 +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
@@ -1273,8 +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;
@@ -1445,6 +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 +1,138 @@
+// Copyright (c) 2025 The Bitcoin Knots 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 <cassert>
+#include <QWindow>
+
+#include <windows.h>
+#include <shobjidl.h>
+
+WinTaskbarProgress::WinTaskbarProgress()
+{
+}
+
+WinTaskbarProgress::~WinTaskbarProgress()
+{
+    releaseTaskbar();
+}
+
+void WinTaskbarProgress::setWindow(QWindow* window)
+{
+    assert(!m_initialized);
+    m_window = window;
+}
+
+void WinTaskbarProgress::initializeTaskbar()
+{
+    if (m_initialized || !m_window) {
+        return;
+    }
+
+    HWND winId = reinterpret_cast<HWND>(m_window->winId());
+    if (!winId) {
+        return;
+    }
+
+    HRESULT hr = CoCreateInstance(
+        CLSID_TaskbarList,
+        nullptr,
+        CLSCTX_INPROC_SERVER,
+        IID_ITaskbarList3,
+        reinterpret_cast<void**>(&m_taskbarList)
+    );
+
+    if (SUCCEEDED(hr) && m_taskbarList) {
+        hr = m_taskbarList->HrInit();
+        if (SUCCEEDED(hr)) {
+            m_initialized = true;
+        } else {
+            m_taskbarList->Release();
+            m_taskbarList = nullptr;
+        }
+    }
+}
+
+void WinTaskbarProgress::releaseTaskbar()
+{
+    if (m_taskbarList) {
+        // Clear progress state before releasing
+        if (m_window) {
+            HWND winId = reinterpret_cast<HWND>(m_window->winId());
+            if (winId) {
+                m_taskbarList->SetProgressState(winId, TBPF_NOPROGRESS);
+            }
+        }
+        m_taskbarList->Release();
+        m_taskbarList = nullptr;
+    }
+    m_initialized = false;
+    m_visible = false;
+}
+
+void WinTaskbarProgress::setValue(int value)
+{
+    // Lazy initialization on first use
+    if (!m_initialized) {
+        initializeTaskbar();
+    }
+
+    if (!m_initialized || !m_taskbarList || !m_window) {
+        return;
+    }
+
+    HWND winId = reinterpret_cast<HWND>(m_window->winId());
+    if (!winId) {
+        return;
+    }
+
+    // Clamp value to 0-100
+    if (value < 0) value = 0;
+    if (value > 100) value = 100;
+
+    // Use indeterminate mode for very low progress (< 1%) to show activity
+    // Otherwise progress of 0 is invisible on the taskbar
+    if (value < 1) {
+        m_taskbarList->SetProgressState(winId, TBPF_INDETERMINATE);
+        m_visible = true;
+        return;
+    }
+
+    // Switch to normal mode if not already visible
+    if (!m_visible) {
+        m_taskbarList->SetProgressState(winId, TBPF_NORMAL);
+        m_visible = true;
+    }
+
+    // Set progress value (current, maximum)
+    m_taskbarList->SetProgressValue(winId, value, 100);
+}
+
+void WinTaskbarProgress::setVisible(bool visible)
+{
+    if (!m_initialized || !m_taskbarList || !m_window) {
+        return;
+    }
+
+    HWND winId = reinterpret_cast<HWND>(m_window->winId());
+    if (!winId) {
+        return;
+    }
+
+    if (visible && !m_visible) {
+        // Show normal progress
+        m_taskbarList->SetProgressState(winId, TBPF_NORMAL);
+        m_visible = true;
+    } else if (!visible && m_visible) {
+        // Hide progress
+        m_taskbarList->SetProgressState(winId, TBPF_NOPROGRESS);
+        m_visible = false;
+    }
+}
+
+void WinTaskbarProgress::reset()
+{
+    setVisible(false);
+}

src/qt/wintaskbarprogress.h

@@ -0,0 +1,54 @@
+// Copyright (c) 2025 The Bitcoin Knots 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
+
+#ifdef BITCOIN_QT_WIN_TASKBAR
+#include <QWindow>
+
+#include <windows.h>
+
+// Forward declarations for COM interfaces
+struct ITaskbarList3;
+
+/**
+ * Native Windows taskbar progress indicator
+ * Uses ITaskbarList3 COM interface for Windows 7+ compatibility
+ * Works with both Qt5 and Qt6
+ */
+class WinTaskbarProgress
+{
+public:
+    WinTaskbarProgress();
+    ~WinTaskbarProgress();
+
+    /** Set the window handle to attach progress to */
+    void setWindow(QWindow* window);
+
+    /** Get the window handle */
+    QWindow* window() const { return m_window; }
+
+    /** Set progress value (0-100) */
+    void setValue(int value);
+
+    /** Show or hide the progress indicator */
+    void setVisible(bool visible);
+
+    /** Reset progress state */
+    void reset();
+
+private:
+    QWindow* m_window{nullptr};
+    ITaskbarList3* m_taskbarList{nullptr};
+    bool m_initialized{false};
+    bool m_visible{false};
+
+    void initializeTaskbar();
+    void releaseTaskbar();
+};
+
+#endif // BITCOIN_QT_WIN_TASKBAR
+
+#endif // BITCOIN_QT_WINTASKBARPROGRESS_H