Windows: Provide a way to switch between WinTab and Windows Ink at run-time

This change adds the setWinTabEnabled() function to Qt Platform Headers,
which allows an application to set at run-time whether the WinTab API will
be used for tablet input instead of the native Windows Ink API.

[ChangeLog][Windows] The setWinTabEnabled() function added to Qt Platform
Headers now allows an application to set at run-time whether the WinTab API
will be used for tablet input instead of the native Windows Ink API.

Fixes: QTBUG-83218
Change-Id: I51d3c7316baeda136763cf37c2f54295905450ec
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
Reviewed-by: Shawn Rutledge <shawn.rutledge@qt.io>
Reviewed-by: Oliver Wolff <oliver.wolff@qt.io>

1 files changed, 26 insertions, 4 deletions

diff --git a/src/plugins/platforms/windows/qwindowsintegration.cpp b/src/plugins/platforms/windows/qwindowsintegration.cpp
index 977b5903a5..2c87e80ec7 100644
--- a/src/plugins/platforms/windows/qwindowsintegration.cpp
+++ b/src/plugins/platforms/windows/qwindowsintegration.cpp
@@ -140,6 +140,7 @@ struct QWindowsIntegrationPrivate
     ~QWindowsIntegrationPrivate();
 
     unsigned m_options = 0;
+    int m_tabletAbsoluteRange = -1;
     QWindowsContext m_context;
     QPlatformFontDatabase *m_fontDatabase = nullptr;
 #if QT_CONFIG(clipboard)
@@ -239,19 +240,18 @@ QWindowsIntegrationPrivate::QWindowsIntegrationPrivate(const QStringList &paramL
     initOpenGlBlacklistResources();
 
     static bool dpiAwarenessSet = false;
-    int tabletAbsoluteRange = -1;
     // Default to per-monitor awareness to avoid being scaled when monitors with different DPI
     // are connected to Windows 8.1
     QtWindows::ProcessDpiAwareness dpiAwareness = QtWindows::ProcessPerMonitorDpiAware;
-    m_options = parseOptions(paramList, &tabletAbsoluteRange, &dpiAwareness);
+    m_options = parseOptions(paramList, &m_tabletAbsoluteRange, &dpiAwareness);
     QWindowsFontDatabase::setFontOptions(m_options);
 
     if (m_context.initPointer(m_options)) {
         QCoreApplication::setAttribute(Qt::AA_CompressHighFrequencyEvents);
     } else {
         m_context.initTablet(m_options);
-        if (tabletAbsoluteRange >= 0)
-            m_context.setTabletAbsoluteRange(tabletAbsoluteRange);
+        if (m_tabletAbsoluteRange >= 0)
+            m_context.setTabletAbsoluteRange(m_tabletAbsoluteRange);
     }
 
     if (!dpiAwarenessSet) { // Set only once in case of repeated instantiations of QGuiApplication.
@@ -642,6 +642,28 @@ void QWindowsIntegration::beep() const
     MessageBeep(MB_OK);  // For QApplication
 }
 
+bool QWindowsIntegration::setWinTabEnabled(bool enabled)
+{
+    bool ret = false;
+    if (QWindowsIntegration *p = QWindowsIntegration::instance()) {
+        if (enabled) {
+            if (p->d->m_context.tabletSupport()) {
+                ret = true;
+            } else {
+                ret = p->d->m_context.initTablet(p->d->m_options);
+                if (ret && p->d->m_tabletAbsoluteRange >= 0)
+                    p->d->m_context.setTabletAbsoluteRange(p->d->m_tabletAbsoluteRange);
+            }
+        } else {
+            if (p->d->m_context.tabletSupport())
+                ret = p->d->m_context.disposeTablet();
+            else
+                ret = true;
+        }
+    }
+    return ret;
+}
+
 #if QT_CONFIG(vulkan)
 QPlatformVulkanInstance *QWindowsIntegration::createPlatformVulkanInstance(QVulkanInstance *instance) const
 {