Windows: Fix the size of drag cursors in multi-screen setups.

Move QWindowsDrag::defaultCursor() to the per-screen instance
of QWindowsCursor so that the cached default drag cursor pixmaps
are created with the correct size per screen.

Task-number: QTBUG-49511
Change-Id: I02f75ac3b1e5e064325b066ee03e1d5c8a7c7ee8
Reviewed-by: Joerg Bornemann <joerg.bornemann@theqtcompany.com>

4 files changed, 111 insertions, 105 deletions

diff --git a/src/plugins/platforms/windows/qwindowscursor.cpp b/src/plugins/platforms/windows/qwindowscursor.cpp
index c138335b4b..c769eb04a4 100644
--- a/src/plugins/platforms/windows/qwindowscursor.cpp
+++ b/src/plugins/platforms/windows/qwindowscursor.cpp
@@ -692,6 +692,94 @@ void QWindowsCursor::setPos(const QPoint &pos)
     SetCursorPos(pos.x() , pos.y());
 }
 
+QPixmap QWindowsCursor::dragDefaultCursor(Qt::DropAction action) const
+{
+    switch (action) {
+    case Qt::CopyAction:
+        if (m_copyDragCursor.isNull())
+            m_copyDragCursor = QWindowsCursor::customCursor(Qt::DragCopyCursor, m_screen).pixmap;
+        return m_copyDragCursor;
+    case Qt::TargetMoveAction:
+    case Qt::MoveAction:
+        if (m_moveDragCursor.isNull())
+            m_moveDragCursor = QWindowsCursor::customCursor(Qt::DragMoveCursor, m_screen).pixmap;
+        return m_moveDragCursor;
+    case Qt::LinkAction:
+        if (m_linkDragCursor.isNull())
+            m_linkDragCursor = QWindowsCursor::customCursor(Qt::DragLinkCursor, m_screen).pixmap;
+        return m_linkDragCursor;
+    default:
+        break;
+    }
+
+    static const char * const ignoreDragCursorXpmC[] = {
+    "24 30 3 1",
+    ".        c None",
+    "a        c #000000",
+    "X        c #FFFFFF",
+    "aa......................",
+    "aXa.....................",
+    "aXXa....................",
+    "aXXXa...................",
+    "aXXXXa..................",
+    "aXXXXXa.................",
+    "aXXXXXXa................",
+    "aXXXXXXXa...............",
+    "aXXXXXXXXa..............",
+    "aXXXXXXXXXa.............",
+    "aXXXXXXaaaa.............",
+    "aXXXaXXa................",
+    "aXXaaXXa................",
+    "aXa..aXXa...............",
+    "aa...aXXa...............",
+    "a.....aXXa..............",
+    "......aXXa.....XXXX.....",
+    ".......aXXa..XXaaaaXX...",
+    ".......aXXa.XaaaaaaaaX..",
+    "........aa.XaaaXXXXaaaX.",
+    "...........XaaaaX..XaaX.",
+    "..........XaaXaaaX..XaaX",
+    "..........XaaXXaaaX.XaaX",
+    "..........XaaX.XaaaXXaaX",
+    "..........XaaX..XaaaXaaX",
+    "...........XaaX..XaaaaX.",
+    "...........XaaaXXXXaaaX.",
+    "............XaaaaaaaaX..",
+    ".............XXaaaaXX...",
+    "...............XXXX....."};
+
+    if (m_ignoreDragCursor.isNull()) {
+#if !defined (Q_OS_WINCE)
+        HCURSOR cursor = LoadCursor(NULL, IDC_NO);
+        ICONINFO iconInfo = {0, 0, 0, 0, 0};
+        GetIconInfo(cursor, &iconInfo);
+        BITMAP bmColor = {0, 0, 0, 0, 0, 0, 0};
+
+        if (iconInfo.hbmColor
+            && GetObject(iconInfo.hbmColor, sizeof(BITMAP), &bmColor)
+            && bmColor.bmWidth == bmColor.bmWidthBytes / 4) {
+            const int colorBitsLength = bmColor.bmHeight * bmColor.bmWidthBytes;
+            uchar *colorBits = new uchar[colorBitsLength];
+            GetBitmapBits(iconInfo.hbmColor, colorBitsLength, colorBits);
+            const QImage colorImage(colorBits, bmColor.bmWidth, bmColor.bmHeight,
+                                    bmColor.bmWidthBytes, QImage::Format_ARGB32);
+
+            m_ignoreDragCursor = QPixmap::fromImage(colorImage);
+            delete [] colorBits;
+        } else {
+            m_ignoreDragCursor = QPixmap(ignoreDragCursorXpmC);
+        }
+
+        DeleteObject(iconInfo.hbmMask);
+        DeleteObject(iconInfo.hbmColor);
+        DestroyCursor(cursor);
+#else // !Q_OS_WINCE
+        m_ignoreDragCursor = QPixmap(ignoreDragCursorXpmC);
+#endif // !Q_OS_WINCE
+    }
+    return m_ignoreDragCursor;
+}
+
 /*!
     \class QWindowsWindowCursor
     \brief Per-Window cursor. Contains a QCursor and manages its associated system
diff --git a/src/plugins/platforms/windows/qwindowscursor.h b/src/plugins/platforms/windows/qwindowscursor.h
index 558e807201..e93f779f94 100644
--- a/src/plugins/platforms/windows/qwindowscursor.h
+++ b/src/plugins/platforms/windows/qwindowscursor.h
@@ -113,6 +113,8 @@ public:
     CursorHandlePtr standardWindowCursor(Qt::CursorShape s = Qt::ArrowCursor);
     CursorHandlePtr pixmapWindowCursor(const QCursor &c);
 
+    QPixmap dragDefaultCursor(Qt::DropAction action) const;
+
 private:
     typedef QHash<Qt::CursorShape, CursorHandlePtr> StandardCursorCache;
     typedef QHash<QWindowsPixmapCursorCacheKey, CursorHandlePtr> PixmapCursorCache;
@@ -120,6 +122,11 @@ private:
     const QPlatformScreen *const m_screen;
     StandardCursorCache m_standardCursorCache;
     PixmapCursorCache m_pixmapCursorCache;
+
+    mutable QPixmap m_copyDragCursor;
+    mutable QPixmap m_moveDragCursor;
+    mutable QPixmap m_linkDragCursor;
+    mutable QPixmap m_ignoreDragCursor;
 };
 
 QT_END_NAMESPACE
diff --git a/src/plugins/platforms/windows/qwindowsdrag.cpp b/src/plugins/platforms/windows/qwindowsdrag.cpp
index e16bb80714..021058fa33 100644
--- a/src/plugins/platforms/windows/qwindowsdrag.cpp
+++ b/src/plugins/platforms/windows/qwindowsdrag.cpp
@@ -271,13 +271,6 @@ QDebug operator<<(QDebug d, const QWindowsOleDropSource::CursorEntry &e)
 }
 #endif // !QT_NO_DEBUG_STREAM
 
-static qreal dragScaleFactor()
-{
-    const QWindowsScreenManager &screenManager = QWindowsContext::instance()->screenManager();
-    const QWindowsScreen *screen = screenManager.screenAtDp(QWindowsCursor::mousePosition());
-    return screen ? QHighDpiScaling::factor(screen) : qreal(1);
-}
-
 /*!
     \brief Blend custom pixmap with cursors.
 */
@@ -288,7 +281,17 @@ void QWindowsOleDropSource::createCursors()
     const QPixmap pixmap = drag->pixmap();
     const bool hasPixmap = !pixmap.isNull();
 
-    const qreal scaleFactor = dragScaleFactor();
+    // Find screen for drag. Could be obtained from QDrag::source(), but that might be a QWidget.
+
+    qreal scaleFactor = 1;
+    QPlatformCursor *platformCursor = Q_NULLPTR;
+    if (const QPlatformScreen *platformScreen = QWindowsContext::instance()->screenManager().screenAtDp(QWindowsCursor::mousePosition())) {
+        scaleFactor = QHighDpiScaling::factor(platformScreen);
+        platformCursor = platformScreen->cursor();
+    }
+    if (!platformCursor && QGuiApplication::primaryScreen())
+        platformCursor = QGuiApplication::primaryScreen()->handle()->cursor();
+
     const bool scalePixmap = hasPixmap
         && m_mode != TouchDrag // Touch drag: pixmap is shown in a separate QWindow, which will be scaled.
         && (scaleFactor != 1 && scaleFactor != qRound(pixmap.devicePixelRatio()));
@@ -306,8 +309,8 @@ void QWindowsOleDropSource::createCursors()
     for (int cnum = 0; cnum < actionCount; ++cnum) {
         const Qt::DropAction action = actions[cnum];
         QPixmap cursorPixmap = drag->dragCursor(action);
-        if (cursorPixmap.isNull())
-            cursorPixmap = m_drag->defaultCursor(action);
+        if (cursorPixmap.isNull() && platformCursor)
+            cursorPixmap = static_cast<QWindowsCursor *>(platformCursor)->dragDefaultCursor(action);
         const qint64 cacheKey = cursorPixmap.cacheKey();
         const ActionCursorMapIt it = m_cursors.find(action);
         if (it != m_cursors.end() && it.value().cacheKey == cacheKey)
@@ -704,94 +707,6 @@ IDropTargetHelper* QWindowsDrag::dropHelper() {
     return m_cachedDropTargetHelper;
 }
 
-QPixmap QWindowsDrag::defaultCursor(Qt::DropAction action) const
-{
-    switch (action) {
-    case Qt::CopyAction:
-        if (m_copyDragCursor.isNull())
-            m_copyDragCursor = QWindowsCursor::customCursor(Qt::DragCopyCursor).pixmap;
-        return m_copyDragCursor;
-    case Qt::TargetMoveAction:
-    case Qt::MoveAction:
-        if (m_moveDragCursor.isNull())
-            m_moveDragCursor = QWindowsCursor::customCursor(Qt::DragMoveCursor).pixmap;
-        return m_moveDragCursor;
-    case Qt::LinkAction:
-        if (m_linkDragCursor.isNull())
-            m_linkDragCursor = QWindowsCursor::customCursor(Qt::DragLinkCursor).pixmap;
-        return m_linkDragCursor;
-    default:
-        break;
-    }
-
-    static const char * const ignoreDragCursorXpmC[] = {
-    "24 30 3 1",
-    ".        c None",
-    "a        c #000000",
-    "X        c #FFFFFF",
-    "aa......................",
-    "aXa.....................",
-    "aXXa....................",
-    "aXXXa...................",
-    "aXXXXa..................",
-    "aXXXXXa.................",
-    "aXXXXXXa................",
-    "aXXXXXXXa...............",
-    "aXXXXXXXXa..............",
-    "aXXXXXXXXXa.............",
-    "aXXXXXXaaaa.............",
-    "aXXXaXXa................",
-    "aXXaaXXa................",
-    "aXa..aXXa...............",
-    "aa...aXXa...............",
-    "a.....aXXa..............",
-    "......aXXa.....XXXX.....",
-    ".......aXXa..XXaaaaXX...",
-    ".......aXXa.XaaaaaaaaX..",
-    "........aa.XaaaXXXXaaaX.",
-    "...........XaaaaX..XaaX.",
-    "..........XaaXaaaX..XaaX",
-    "..........XaaXXaaaX.XaaX",
-    "..........XaaX.XaaaXXaaX",
-    "..........XaaX..XaaaXaaX",
-    "...........XaaX..XaaaaX.",
-    "...........XaaaXXXXaaaX.",
-    "............XaaaaaaaaX..",
-    ".............XXaaaaXX...",
-    "...............XXXX....."};
-
-    if (m_ignoreDragCursor.isNull()) {
-#if !defined (Q_OS_WINCE)
-        HCURSOR cursor = LoadCursor(NULL, IDC_NO);
-        ICONINFO iconInfo = {0, 0, 0, 0, 0};
-        GetIconInfo(cursor, &iconInfo);
-        BITMAP bmColor = {0, 0, 0, 0, 0, 0, 0};
-
-        if (iconInfo.hbmColor
-            && GetObject(iconInfo.hbmColor, sizeof(BITMAP), &bmColor)
-            && bmColor.bmWidth == bmColor.bmWidthBytes / 4) {
-            const int colorBitsLength = bmColor.bmHeight * bmColor.bmWidthBytes;
-            uchar *colorBits = new uchar[colorBitsLength];
-            GetBitmapBits(iconInfo.hbmColor, colorBitsLength, colorBits);
-            const QImage colorImage(colorBits, bmColor.bmWidth, bmColor.bmHeight,
-                                    bmColor.bmWidthBytes, QImage::Format_ARGB32);
-
-            m_ignoreDragCursor = QPixmap::fromImage(colorImage);
-            delete [] colorBits;
-        } else {
-            m_ignoreDragCursor = QPixmap(ignoreDragCursorXpmC);
-        }
-
-        DeleteObject(iconInfo.hbmMask);
-        DeleteObject(iconInfo.hbmColor);
-        DestroyCursor(cursor);
-#else // !Q_OS_WINCE
-        m_ignoreDragCursor = QPixmap(ignoreDragCursorXpmC);
-#endif // !Q_OS_WINCE
-    }
-    return m_ignoreDragCursor;
-}
-
 Qt::DropAction QWindowsDrag::drag(QDrag *drag)
 {
     // TODO: Accessibility handling?
diff --git a/src/plugins/platforms/windows/qwindowsdrag.h b/src/plugins/platforms/windows/qwindowsdrag.h
index 9a5e0b17f2..890ad6c142 100644
--- a/src/plugins/platforms/windows/qwindowsdrag.h
+++ b/src/plugins/platforms/windows/qwindowsdrag.h
@@ -42,6 +42,9 @@
 struct IDropTargetHelper;
 
 QT_BEGIN_NAMESPACE
+
+class QPlatformScreen;
+
 class QWindowsDropMimeData : public QWindowsInternalMimeData {
 public:
     QWindowsDropMimeData() {}
@@ -95,18 +98,11 @@ public:
 
     IDropTargetHelper* dropHelper();
 
-    QPixmap defaultCursor(Qt::DropAction action) const;
-
 private:
     QWindowsDropMimeData m_dropData;
     IDataObject *m_dropDataObject;
 
     IDropTargetHelper* m_cachedDropTargetHelper;
-
-    mutable QPixmap m_copyDragCursor;
-    mutable QPixmap m_moveDragCursor;
-    mutable QPixmap m_linkDragCursor;
-    mutable QPixmap m_ignoreDragCursor;
 };
 
 QT_END_NAMESPACE