Highdpi changes for Windows

Adapt the Windows plugin to work with the new cross-platform
high-DPI scaling.

Task-number: QTBUG-38993
Task-number: QTBUG-46615
Change-Id: I108d319255925a290b75611e95ef006d4aaf7ace
Reviewed-by: Lars Knoll <lars.knoll@theqtcompany.com>

8 files changed, 65 insertions, 17 deletions

diff --git a/src/plugins/platforms/windows/qwindowsbackingstore.cpp b/src/plugins/platforms/windows/qwindowsbackingstore.cpp
index fe56d3dddc..3f19e4401a 100644
--- a/src/plugins/platforms/windows/qwindowsbackingstore.cpp
+++ b/src/plugins/platforms/windows/qwindowsbackingstore.cpp
@@ -38,6 +38,7 @@
 
 #include <QtGui/QWindow>
 #include <QtGui/QPainter>
+#include <private/qhighdpiscaling_p.h>
 
 #include <QtCore/QDebug>
 
@@ -82,8 +83,8 @@ void QWindowsBackingStore::flush(QWindow *window, const QRegion &region,
     const Qt::WindowFlags flags = window->flags();
     if ((flags & Qt::FramelessWindowHint) && QWindowsWindow::setWindowLayered(rw->handle(), flags, hasAlpha, rw->opacity()) && hasAlpha) {
         // Windows with alpha: Use blend function to update.
-        QRect r = window->frameGeometry();
-        QPoint frameOffset(window->frameMargins().left(), window->frameMargins().top());
+        QRect r = QHighDpi::toNativePixels(window->frameGeometry(), window);
+        QPoint frameOffset(QHighDpi::toNativePixels(QPoint(window->frameMargins().left(), window->frameMargins().top()), window));
         QRect dirtyRect = br.translated(offset + frameOffset);
 
         SIZE size = {r.width(), r.height()};
diff --git a/src/plugins/platforms/windows/qwindowsdrag.cpp b/src/plugins/platforms/windows/qwindowsdrag.cpp
index 65ea7ea210..d24cba3c68 100644
--- a/src/plugins/platforms/windows/qwindowsdrag.cpp
+++ b/src/plugins/platforms/windows/qwindowsdrag.cpp
@@ -33,6 +33,7 @@
 
 #include "qwindowsdrag.h"
 #include "qwindowscontext.h"
+#include "qwindowsscreen.h"
 #ifndef QT_NO_CLIPBOARD
 #  include "qwindowsclipboard.h"
 #endif
@@ -50,6 +51,7 @@
 #include <QtGui/QGuiApplication>
 #include <qpa/qwindowsysteminterface_p.h>
 #include <QtGui/private/qguiapplication_p.h>
+#include <QtGui/private/qhighdpiscaling_p.h>
 
 #include <QtCore/QDebug>
 #include <QtCore/QBuffer>
@@ -278,6 +280,13 @@ QDebug operator<<(QDebug d, const QWindowsOleDropSource::CursorEntry &e)
 }
 #endif // !QT_NO_DEBUG_OUTPUT
 
+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.
 */
@@ -288,11 +297,21 @@ void QWindowsOleDropSource::createCursors()
     const QPixmap pixmap = drag->pixmap();
     const bool hasPixmap = !pixmap.isNull();
 
+    const qreal scaleFactor = dragScaleFactor();
+    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()));
+    const QPixmap scaledPixmap = scalePixmap
+        ? pixmap.scaled((QSizeF(pixmap.size()) * scaleFactor).toSize(),
+                        Qt::KeepAspectRatio, Qt::SmoothTransformation)
+        : pixmap;
     Qt::DropAction actions[] = { Qt::MoveAction, Qt::CopyAction, Qt::LinkAction, Qt::IgnoreAction };
     int actionCount = int(sizeof(actions) / sizeof(actions[0]));
     if (!hasPixmap)
         --actionCount; // No Qt::IgnoreAction unless pixmap
-    const QPoint hotSpot = drag->hotSpot();
+    const QPoint hotSpot = scalePixmap
+        ? (QPointF(drag->hotSpot()) * scaleFactor).toPoint()
+        : drag->hotSpot();
     for (int cnum = 0; cnum < actionCount; ++cnum) {
         const Qt::DropAction action = actions[cnum];
         QPixmap cursorPixmap = drag->dragCursor(action);
@@ -312,15 +331,14 @@ void QWindowsOleDropSource::createCursors()
 
         if (hasPixmap) {
             const int x1 = qMin(-hotSpot.x(), 0);
-            const int x2 = qMax(pixmap.width() - hotSpot.x(), cursorPixmap.width());
+            const int x2 = qMax(scaledPixmap.width() - hotSpot.x(), cursorPixmap.width());
             const int y1 = qMin(-hotSpot.y(), 0);
-            const int y2 = qMax(pixmap.height() - hotSpot.y(), cursorPixmap.height());
+            const int y2 = qMax(scaledPixmap.height() - hotSpot.y(), cursorPixmap.height());
             QPixmap newCursor(x2 - x1 + 1, y2 - y1 + 1);
             newCursor.fill(Qt::transparent);
             QPainter p(&newCursor);
-            const QRect srcRect = pixmap.rect();
             const QPoint pmDest = QPoint(qMax(0, -hotSpot.x()), qMax(0, -hotSpot.y()));
-            p.drawPixmap(pmDest, pixmap, srcRect);
+            p.drawPixmap(pmDest, scaledPixmap);
             p.drawPixmap(qMax(0, hotSpot.x()),qMax(0, hotSpot.y()), cursorPixmap);
             newPixmap = newCursor;
             newHotSpot = QPoint(qMax(0, hotSpot.x()), qMax(0, hotSpot.y()));
diff --git a/src/plugins/platforms/windows/qwindowsintegration.cpp b/src/plugins/platforms/windows/qwindowsintegration.cpp
index 26e071cba1..05c7e6b240 100644
--- a/src/plugins/platforms/windows/qwindowsintegration.cpp
+++ b/src/plugins/platforms/windows/qwindowsintegration.cpp
@@ -63,6 +63,7 @@
 #  include "qwindowssessionmanager.h"
 #endif
 #include <QtGui/private/qguiapplication_p.h>
+#include <QtGui/private/qhighdpiscaling_p.h>
 #include <QtGui/qpa/qplatforminputcontextfactory_p.h>
 
 #include <QtCore/private/qeventdispatcher_win_p.h>
@@ -302,7 +303,7 @@ QWindowsWindowData QWindowsIntegration::createWindowData(QWindow *window) const
 {
     QWindowsWindowData requested;
     requested.flags = window->flags();
-    requested.geometry = window->geometry();
+    requested.geometry = QHighDpi::toNativePixels(window->geometry(), window);
     // Apply custom margins (see  QWindowsWindow::setCustomMargins())).
     const QVariant customMarginsV = window->property("_q_windowsCustomMargins");
     if (customMarginsV.isValid())
diff --git a/src/plugins/platforms/windows/qwindowskeymapper.cpp b/src/plugins/platforms/windows/qwindowskeymapper.cpp
index e6fec9c8f4..3636bb7893 100644
--- a/src/plugins/platforms/windows/qwindowskeymapper.cpp
+++ b/src/plugins/platforms/windows/qwindowskeymapper.cpp
@@ -40,6 +40,7 @@
 #include <QtGui/QWindow>
 #include <qpa/qwindowsysteminterface.h>
 #include <private/qguiapplication_p.h>
+#include <private/qhighdpiscaling_p.h>
 #include <QtGui/QKeyEvent>
 
 #if defined(WM_APPCOMMAND)
@@ -791,9 +792,10 @@ static void showSystemMenu(QWindow* w)
 #undef enabled
 #undef disabled
 #endif // !Q_OS_WINCE
+    const QPoint pos = QHighDpi::toNativePixels(topLevel->geometry().topLeft(), topLevel);
     const int ret = TrackPopupMenuEx(menu,
                                TPM_LEFTALIGN  | TPM_TOPALIGN | TPM_NONOTIFY | TPM_RETURNCMD,
-                               topLevel->geometry().x(), topLevel->geometry().y(),
+                               pos.x(), pos.y(),
                                topLevelHwnd,
                                0);
     if (ret)
diff --git a/src/plugins/platforms/windows/qwindowsscreen.cpp b/src/plugins/platforms/windows/qwindowsscreen.cpp
index 5863629a01..391735a035 100644
--- a/src/plugins/platforms/windows/qwindowsscreen.cpp
+++ b/src/plugins/platforms/windows/qwindowsscreen.cpp
@@ -43,6 +43,7 @@
 #include <QtGui/QPixmap>
 #include <QtGui/QGuiApplication>
 #include <qpa/qwindowsysteminterface.h>
+#include <private/qhighdpiscaling_p.h>
 #include <QtGui/QScreen>
 
 #include <QtCore/QDebug>
@@ -287,6 +288,12 @@ QWindowsScreen *QWindowsScreen::screenOf(const QWindow *w)
     return 0;
 }
 
+qreal QWindowsScreen::pixelDensity() const
+{
+    const qreal physicalDpi = m_data.geometry.width() / m_data.physicalSizeMM.width() * qreal(25.4);
+    return qRound(physicalDpi / 96);
+}
+
 /*!
     \brief Determine siblings in a virtual desktop system.
 
diff --git a/src/plugins/platforms/windows/qwindowsscreen.h b/src/plugins/platforms/windows/qwindowsscreen.h
index 76161b2ae7..67e7ff644b 100644
--- a/src/plugins/platforms/windows/qwindowsscreen.h
+++ b/src/plugins/platforms/windows/qwindowsscreen.h
@@ -87,6 +87,7 @@ public:
     QImage::Format format() const Q_DECL_OVERRIDE { return m_data.format; }
     QSizeF physicalSize() const Q_DECL_OVERRIDE { return m_data.physicalSizeMM; }
     QDpi logicalDpi() const Q_DECL_OVERRIDE { return m_data.dpi; }
+    qreal pixelDensity() const Q_DECL_OVERRIDE;
     qreal devicePixelRatio() const Q_DECL_OVERRIDE { return 1.0; }
     qreal refreshRate() const Q_DECL_OVERRIDE { return m_data.refreshRateHz; }
     QString name() const Q_DECL_OVERRIDE { return m_data.name; }
diff --git a/src/plugins/platforms/windows/qwindowstheme.cpp b/src/plugins/platforms/windows/qwindowstheme.cpp
index a000f107a9..a541fd4629 100644
--- a/src/plugins/platforms/windows/qwindowstheme.cpp
+++ b/src/plugins/platforms/windows/qwindowstheme.cpp
@@ -67,6 +67,7 @@
 #include <QtGui/QPainter>
 #include <QtGui/QPixmapCache>
 #include <qpa/qwindowsysteminterface.h>
+#include <private/qhighdpiscaling_p.h>
 #include <private/qsystemlibrary_p.h>
 
 #include <algorithm>
@@ -494,7 +495,8 @@ static QPixmap loadIconFromShell32(int resourceId, QSizeF size)
 
 QPixmap QWindowsTheme::standardPixmap(StandardPixmap sp, const QSizeF &size) const
 {
-    const int scaleFactor = 1; // HIGDPI Fixme: ?
+    const QScreen *primaryScreen = QGuiApplication::primaryScreen();
+    const int scaleFactor = primaryScreen ? qRound(QHighDpiScaling::factor(primaryScreen)) : 1;
     const QSizeF pixmapSize = size * scaleFactor;
     int resourceId = -1;
     LPCTSTR iconName = 0;
diff --git a/src/plugins/platforms/windows/qwindowswindow.cpp b/src/plugins/platforms/windows/qwindowswindow.cpp
index 78e6315705..87747a74fd 100644
--- a/src/plugins/platforms/windows/qwindowswindow.cpp
+++ b/src/plugins/platforms/windows/qwindowswindow.cpp
@@ -50,6 +50,7 @@
 #include <private/qsystemlibrary_p.h>
 #include <private/qwindow_p.h> // QWINDOWSIZE_MAX
 #include <private/qguiapplication_p.h>
+#include <private/qhighdpiscaling_p.h>
 #include <qpa/qwindowsysteminterface.h>
 
 #include <QtCore/QDebug>
@@ -703,6 +704,20 @@ void WindowCreationData::initialize(const QWindow *w, HWND hwnd, bool frameChang
     }
 }
 
+
+// Scaling helpers for size constraints.
+static QSize toNativeSizeConstrained(QSize dip, const QWindow *w)
+{
+    if (QHighDpiScaling::isActive()) {
+        const qreal factor = QHighDpiScaling::factor(w);
+        if (dip.width() > 0 && dip.width() < QWINDOWSIZE_MAX)
+            dip.rwidth() *= factor;
+        if (dip.height() > 0 && dip.height() < QWINDOWSIZE_MAX)
+            dip.rheight() *= factor;
+    }
+    return dip;
+}
+
 /*!
     \class QWindowsGeometryHint
     \brief Stores geometry constraints and provides utility functions.
@@ -715,8 +730,8 @@ void WindowCreationData::initialize(const QWindow *w, HWND hwnd, bool frameChang
 */
 
 QWindowsGeometryHint::QWindowsGeometryHint(const QWindow *w, const QMargins &cm) :
-     minimumSize(w->minimumSize()),
-     maximumSize(w->maximumSize()),
+     minimumSize(toNativeSizeConstrained(w->minimumSize(), w)),
+     maximumSize(toNativeSizeConstrained(w->maximumSize(), w)),
      customMargins(cm)
 {
 }
@@ -1621,7 +1636,9 @@ void QWindowsWindow::setWindowState(Qt::WindowState state)
 
 bool QWindowsWindow::isFullScreen_sys() const
 {
-    return window()->isTopLevel() && geometry_sys() == window()->screen()->geometry();
+    const QWindow *w = window();
+    return w->isTopLevel()
+        && geometry_sys() == QHighDpi::toNativePixels(w->screen()->geometry(), w);
 }
 
 /*!
@@ -1691,7 +1708,7 @@ void QWindowsWindow::setWindowState_sys(Qt::WindowState newState)
             // Use geometry of QWindow::screen() within creation or the virtual screen the
             // window is in (QTBUG-31166, QTBUG-30724).
             const QScreen *screen = window()->screen();
-            const QRect r = screen->geometry();
+            const QRect r = QHighDpi::toNativePixels(screen->geometry(), window());
             const UINT swpf = SWP_FRAMECHANGED | SWP_NOACTIVATE;
             const bool wasSync = testFlag(SynchronousGeometryChangeEvent);
             setFlag(SynchronousGeometryChangeEvent);
@@ -1808,8 +1825,7 @@ bool QWindowsWindow::handleGeometryChangingMessage(MSG *message, const QWindow *
     const QRect suggestedFrameGeometry(windowPos->x, windowPos->y,
                                        windowPos->cx, windowPos->cy);
     const QRect suggestedGeometry = suggestedFrameGeometry - margins;
-    const QRectF correctedGeometryF =
-        qt_window_private(const_cast<QWindow *>(qWindow))->closestAcceptableGeometry(suggestedGeometry);
+    const QRectF correctedGeometryF = qWindow->handle()->windowClosestAcceptableGeometry(suggestedGeometry);
     if (!correctedGeometryF.isValid())
         return false;
     const QRect correctedFrameGeometry = correctedGeometryF.toRect() + margins;
@@ -2048,7 +2064,7 @@ bool QWindowsWindow::handleNonClientHitTest(const QPoint &globalPos, LRESULT *re
     const bool fixedHeight = minimumSize.height() == maximumSize.height();
     if (!fixedWidth && !fixedHeight)
         return false;
-    const QPoint localPos = w->mapFromGlobal(globalPos);
+    const QPoint localPos = w->mapFromGlobal(QHighDpi::fromNativePixels(globalPos, w));
     const QSize size = w->size();
     if (fixedHeight) {
         if (localPos.y() >= size.height()) {