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Windows QPA: Fix Drag&Drop from touchscreen/pen

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The Drag&Drop functionality had stopped working with touchscreen/pen
after the WM_POINTER-based input handling was added. The Drag&Drop
functionality internally uses the DoDragDrop() WIN32 call which,
according to Microsoft docs, is not supported for invocation inside
handlers for touch/pen messages, and should be invoked in handlers
for mouse messages that are synthesized by the OS afterwards. The
result was that when DoDragDrop (which is a blocking function with
its own event loop) was called it would hang ignoring all touch/pen
messages until a mouse/touchpad message arrived. This change
implements a workaround for this issue by enqueuing Qt touch/pen
events that would be generated inside the pointer message handler,
and that could start a Drag&Drop operation, and only producing them
after the OS sends the associated mouse messages.

Task-number: QTBUG-70887
Change-Id: Id45e0ecc70358ba250de9b3268856781ed21c9dd
Reviewed-by: Friedemann Kleint <Friedemann.Kleint@qt.io>
This commit is contained in:
Andre de la Rocha 2018-10-16 15:06:04 +02:00
parent 57b09b903e
commit 83d56811ec
3 changed files with 145 additions and 10 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
src/plugins/platforms/windows/qwindowsdrag.cpp
View File

@ -652,6 +652,7 @@ QWindowsOleDropTarget::Drop(LPDATAOBJECT pDataObj, DWORD grfKeyState,
*/
bool QWindowsDrag::m_canceled = false;
bool QWindowsDrag::m_dragging = false;
QWindowsDrag::QWindowsDrag() = default;
@ -699,7 +700,10 @@ Qt::DropAction QWindowsDrag::drag(QDrag *drag)
const DWORD allowedEffects = translateToWinDragEffects(possibleActions);
qCDebug(lcQpaMime) << '>' << __FUNCTION__ << "possible Actions=0x"
<< hex << int(possibleActions) << "effects=0x" << allowedEffects << dec;
// Indicate message handlers we are in DoDragDrop() event loop.
QWindowsDrag::m_dragging = true;
const HRESULT r = DoDragDrop(dropDataObject, windowDropSource, allowedEffects, &resultEffect);
QWindowsDrag::m_dragging = false;
const DWORD reportedPerformedEffect = dropDataObject->reportedPerformedEffect();
if (r == DRAGDROP_S_DROP) {
if (reportedPerformedEffect == DROPEFFECT_MOVE && resultEffect != DROPEFFECT_MOVE) {

2
src/plugins/platforms/windows/qwindowsdrag.h
View File

@ -92,6 +92,7 @@ public:
static QWindowsDrag *instance();
void cancelDrag() override { QWindowsDrag::m_canceled = true; }
static bool isCanceled() { return QWindowsDrag::m_canceled; }
static bool isDragging() { return QWindowsDrag::m_dragging; }
IDataObject *dropDataObject() const { return m_dropDataObject; }
void setDropDataObject(IDataObject *dataObject) { m_dropDataObject = dataObject; }
@ -102,6 +103,7 @@ public:
private:
static bool m_canceled;
static bool m_dragging;
QWindowsDropMimeData m_dropData;
IDataObject *m_dropDataObject = nullptr;

141
src/plugins/platforms/windows/qwindowspointerhandler.cpp
View File

@ -50,6 +50,9 @@
#include "qwindowswindow.h"
#include "qwindowsintegration.h"
#include "qwindowsscreen.h"
#if QT_CONFIG(draganddrop)
# include "qwindowsdrag.h"
#endif
#include <qpa/qwindowsysteminterface.h>
#include <QtGui/qguiapplication.h>
@ -60,6 +63,7 @@
#include <QtCore/qvarlengtharray.h>
#include <QtCore/qloggingcategory.h>
#include <QtCore/qoperatingsystemversion.h>
#include <QtCore/qqueue.h>
#include <algorithm>
@ -75,6 +79,111 @@ enum {
QT_PT_TOUCHPAD = 5, // MinGW is missing PT_TOUCHPAD
};
struct PointerTouchEventInfo {
QPointer<QWindow> window;
QList<QWindowSystemInterface::TouchPoint> points;
Qt::KeyboardModifiers modifiers;
};
struct PointerTabletEventInfo {
QPointer<QWindow> window;
QPointF local;
QPointF global;
int device;
int pointerType;
Qt::MouseButtons buttons;
qreal pressure;
int xTilt;
int yTilt;
qreal tangentialPressure;
qreal rotation;
int z;
qint64 uid;
Qt::KeyboardModifiers modifiers;
};
static QQueue<PointerTouchEventInfo> touchEventQueue;
static QQueue<PointerTabletEventInfo> tabletEventQueue;
static void enqueueTouchEvent(QWindow *window,
const QList<QWindowSystemInterface::TouchPoint> &points,
Qt::KeyboardModifiers modifiers)
{
PointerTouchEventInfo eventInfo;
eventInfo.window = window;
eventInfo.points = points;
eventInfo.modifiers = modifiers;
touchEventQueue.enqueue(eventInfo);
}
static void enqueueTabletEvent(QWindow *window, const QPointF &local, const QPointF &global,
int device, int pointerType, Qt::MouseButtons buttons, qreal pressure,
int xTilt, int yTilt, qreal tangentialPressure, qreal rotation,
int z, qint64 uid, Qt::KeyboardModifiers modifiers)
{
PointerTabletEventInfo eventInfo;
eventInfo.window = window;
eventInfo.local = local;
eventInfo.global = global;
eventInfo.device = device;
eventInfo.pointerType = pointerType;
eventInfo.buttons = buttons;
eventInfo.pressure = pressure;
eventInfo.xTilt = xTilt;
eventInfo.yTilt = yTilt;
eventInfo.tangentialPressure = tangentialPressure;
eventInfo.rotation = rotation;
eventInfo.z = z;
eventInfo.uid = uid;
eventInfo.modifiers = modifiers;
tabletEventQueue.enqueue(eventInfo);
}
static void flushTouchEvents(QTouchDevice *touchDevice)
{
while (!touchEventQueue.isEmpty()) {
PointerTouchEventInfo eventInfo = touchEventQueue.dequeue();
if (eventInfo.window) {
QWindowSystemInterface::handleTouchEvent(eventInfo.window,
touchDevice,
eventInfo.points,
eventInfo.modifiers);
}
}
}
static void flushTabletEvents()
{
while (!tabletEventQueue.isEmpty()) {
PointerTabletEventInfo eventInfo = tabletEventQueue.dequeue();
if (eventInfo.window) {
QWindowSystemInterface::handleTabletEvent(eventInfo.window,
eventInfo.local,
eventInfo.global,
eventInfo.device,
eventInfo.pointerType,
eventInfo.buttons,
eventInfo.pressure,
eventInfo.xTilt,
eventInfo.yTilt,
eventInfo.tangentialPressure,
eventInfo.rotation,
eventInfo.z,
eventInfo.uid,
eventInfo.modifiers);
}
}
}
static bool draggingActive()
{
#if QT_CONFIG(draganddrop)
return QWindowsDrag::isDragging();
#else
return false;
#endif
}
bool QWindowsPointerHandler::translatePointerEvent(QWindow *window, HWND hwnd, QtWindows::WindowsEventType et, MSG msg, LRESULT *result)
{
*result = 0;
@ -426,6 +535,9 @@ bool QWindowsPointerHandler::translateTouchEvent(QWindow *window, HWND hwnd,
if (et & QtWindows::NonClientEventFlag)
return false; // Let DefWindowProc() handle Non Client messages.
if (draggingActive())
return false; // Let DoDragDrop() loop handle it.
if (count < 1)
return false;
@ -452,6 +564,8 @@ bool QWindowsPointerHandler::translateTouchEvent(QWindow *window, HWND hwnd,
QList<QWindowSystemInterface::TouchPoint> touchPoints;
bool primaryPointer = false;
if (QWindowsContext::verbose > 1)
qCDebug(lcQpaEvents).noquote().nospace() << showbase
<< __FUNCTION__
@ -494,16 +608,23 @@ bool QWindowsPointerHandler::translateTouchEvent(QWindow *window, HWND hwnd,
touchPoint.state = stationaryTouchPoint ? Qt::TouchPointStationary : Qt::TouchPointMoved;
m_lastTouchPositions.insert(touchPoint.id, touchPoint.normalPosition);
}
if (touchInfo[i].pointerInfo.pointerFlags & POINTER_FLAG_PRIMARY)
primaryPointer = true;
touchPoints.append(touchPoint);
// Avoid getting repeated messages for this frame if there are multiple pointerIds
QWindowsContext::user32dll.skipPointerFrameMessages(touchInfo[i].pointerInfo.pointerId);
}
if (primaryPointer) {
// Postpone event delivery to avoid hanging inside DoDragDrop().
// Only the primary pointer will generate mouse messages.
enqueueTouchEvent(window, touchPoints, QWindowsKeyMapper::queryKeyboardModifiers());
} else {
QWindowSystemInterface::handleTouchEvent(window, m_touchDevice, touchPoints,
QWindowsKeyMapper::queryKeyboardModifiers());
return true;
}
return false; // Allow mouse messages to be generated.
}
bool QWindowsPointerHandler::translatePenEvent(QWindow *window, HWND hwnd, QtWindows::WindowsEventType et,
@ -512,6 +633,9 @@ bool QWindowsPointerHandler::translatePenEvent(QWindow *window, HWND hwnd, QtWin
if (et & QtWindows::NonClientEventFlag)
return false; // Let DefWindowProc() handle Non Client messages.
if (draggingActive())
return false; // Let DoDragDrop() loop handle it.
POINTER_PEN_INFO *penInfo = static_cast<POINTER_PEN_INFO *>(vPenInfo);
RECT pRect, dRect;
@ -592,20 +716,25 @@ bool QWindowsPointerHandler::translatePenEvent(QWindow *window, HWND hwnd, QtWin
}
const Qt::KeyboardModifiers keyModifiers = QWindowsKeyMapper::queryKeyboardModifiers();
QWindowSystemInterface::handleTabletEvent(target, localPos, hiResGlobalPos, device, type, mouseButtons,
// Postpone event delivery to avoid hanging inside DoDragDrop().
enqueueTabletEvent(target, localPos, hiResGlobalPos, device, type, mouseButtons,
pressure, xTilt, yTilt, tangentialPressure, rotation, z,
pointerId, keyModifiers);
break;
return false; // Allow mouse messages to be generated.
}
}
return true;
}
// SetCursorPos()/TrackMouseEvent() will generate old-style WM_MOUSE messages. Handle them here.
// Process old-style mouse messages here.
bool QWindowsPointerHandler::translateMouseEvent(QWindow *window, HWND hwnd, QtWindows::WindowsEventType et, MSG msg, LRESULT *result)
{
Q_UNUSED(et);
// Generate enqueued events.
flushTouchEvents(m_touchDevice);
flushTabletEvents();
*result = 0;
if (msg.message != WM_MOUSELEAVE && msg.message != WM_MOUSEMOVE)
return false;