wasm: improve event coordinate handling

targetX and targetY are canvas-local coordinates,
while Qt generally works with window-local and global
coordinates.

Add coordinate mapping calls where needed and make
sure we pass correct coordinate types to Qt.

This starts mattering when we have canvases which
are not located at (0, 0).

Change-Id: I28563310ca17d0cc5535317cff99fcd82d3723db
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>

src/plugins/platforms/wasm/qwasmcompositor.cpp

@@ -193,7 +193,7 @@ void QWasmCompositor::requestRedraw()
     QCoreApplication::postEvent(this, new QEvent(QEvent::UpdateRequest));
 }
 
-QWindow *QWasmCompositor::windowAt(QPoint p, int padding) const
+QWindow *QWasmCompositor::windowAt(QPoint globalPoint, int padding) const
 {
     int index = m_windowStack.count() - 1;
     // qDebug() << "window at" << "point" << p << "window count" << index;
@@ -205,7 +205,7 @@ QWindow *QWasmCompositor::windowAt(QPoint p, int padding) const
         QRect geometry = compositedWindow.window->windowFrameGeometry()
                          .adjusted(-padding, -padding, padding, padding);
 
-        if (compositedWindow.visible && geometry.contains(p))
+        if (compositedWindow.visible && geometry.contains(globalPoint))
             return m_windowStack.at(index)->window();
         --index;
     }

src/plugins/platforms/wasm/qwasmcompositor.h

@@ -116,7 +116,7 @@ public:
     void redrawWindowContent();
     void requestRedraw();
 
-    QWindow *windowAt(QPoint p, int padding = 0) const;
+    QWindow *windowAt(QPoint globalPoint, int padding = 0) const;
     QWindow *keyWindow() const;
 
     bool event(QEvent *event);

src/plugins/platforms/wasm/qwasmeventtranslator.cpp

@@ -549,22 +549,22 @@ void resizeWindow(QWindow *window, QWasmWindow::ResizeMode mode,
 void QWasmEventTranslator::processMouse(int eventType, const EmscriptenMouseEvent *mouseEvent)
 {
     auto timestamp = mouseEvent->timestamp;
-    QPoint point(mouseEvent->targetX, mouseEvent->targetY);
+    QPoint targetPoint(mouseEvent->targetX, mouseEvent->targetY);
+    QPoint globalPoint = screen()->geometry().topLeft() + targetPoint;
 
     QEvent::Type buttonEventType = QEvent::None;
-
     Qt::MouseButton button = translateMouseButton(mouseEvent->button);
     Qt::KeyboardModifiers modifiers = translateMouseEventModifier(mouseEvent);
 
-    QWindow *window2 = screen()->compositor()->windowAt(point, 5);
+    QWindow *window2 = screen()->compositor()->windowAt(globalPoint, 5);
-    if (window2 != nullptr)
+    if (window2 == nullptr)
-        lastWindow = window2;
+        return;
+    lastWindow = window2;
+
+    QPoint localPoint = window2->mapFromGlobal(globalPoint);
+    bool interior = window2->geometry().contains(globalPoint);
 
     QWasmWindow *htmlWindow = static_cast<QWasmWindow*>(window2->handle());
-
-    bool interior = window2 && window2->geometry().contains(point);
-
-    QPoint localPoint(point.x() - window2->geometry().x(), point.y() - window2->geometry().y());
     switch (eventType) {
     case EMSCRIPTEN_EVENT_MOUSEDOWN:
     {
@@ -580,18 +580,18 @@ void QWasmEventTranslator::processMouse(int eventType, const EmscriptenMouseEven
             pressedWindow = window2;
             buttonEventType = QEvent::MouseButtonPress;
             if (!(htmlWindow->m_windowState & Qt::WindowFullScreen) && !(htmlWindow->m_windowState & Qt::WindowMaximized)) {
-                if (htmlWindow && window2->flags().testFlag(Qt::WindowTitleHint) && htmlWindow->isPointOnTitle(point))
+                if (htmlWindow && window2->flags().testFlag(Qt::WindowTitleHint) && htmlWindow->isPointOnTitle(globalPoint))
                     draggedWindow = window2;
-                else if (htmlWindow && htmlWindow->isPointOnResizeRegion(point)) {
+                else if (htmlWindow && htmlWindow->isPointOnResizeRegion(globalPoint)) {
                     draggedWindow = window2;
-                    resizeMode = htmlWindow->resizeModeAtPoint(point);
+                    resizeMode = htmlWindow->resizeModeAtPoint(globalPoint);
-                    resizePoint = point;
+                    resizePoint = globalPoint;
                     resizeStartRect = window2->geometry();
                 }
             }
         }
 
-        htmlWindow->injectMousePressed(localPoint, point, button, modifiers);
+        htmlWindow->injectMousePressed(localPoint, globalPoint, button, modifiers);
         break;
     }
     case EMSCRIPTEN_EVENT_MOUSEUP:
@@ -611,7 +611,7 @@ void QWasmEventTranslator::processMouse(int eventType, const EmscriptenMouseEven
         }
 
         if (oldWindow)
-            oldWindow->injectMouseReleased(localPoint, point, button, modifiers);
+            oldWindow->injectMouseReleased(localPoint, globalPoint, button, modifiers);
         break;
     }
     case EMSCRIPTEN_EVENT_MOUSEMOVE: // drag event
@@ -640,7 +640,7 @@ void QWasmEventTranslator::processMouse(int eventType, const EmscriptenMouseEven
     }
     if (window2 && interior) {
         QWindowSystemInterface::handleMouseEvent<QWindowSystemInterface::SynchronousDelivery>(
-            window2, timestamp, localPoint, point, pressedButtons, button, buttonEventType, modifiers);
+            window2, timestamp, localPoint, globalPoint, pressedButtons, button, buttonEventType, modifiers);
     }
 }
 
@@ -675,11 +675,13 @@ int QWasmEventTranslator::wheel_cb(int eventType, const EmscriptenWheelEvent *wh
     QWasmEventTranslator *translator = (QWasmEventTranslator*)userData;
     Qt::KeyboardModifiers modifiers = translator->translateMouseEventModifier(&mouseEvent);
     auto timestamp = mouseEvent.timestamp;
-    QPoint globalPoint(mouseEvent.canvasX, mouseEvent.canvasY);
+    QPoint targetPoint(mouseEvent.targetX, mouseEvent.targetY);
+    QPoint globalPoint = eventTranslator->screen()->geometry().topLeft() + targetPoint;
 
     QWindow *window2 = eventTranslator->screen()->compositor()->windowAt(globalPoint, 5);
-
+    if (!window2)
-    QPoint localPoint(globalPoint.x() - window2->geometry().x(), globalPoint.y() - window2->geometry().y());
+        return 0;
+    QPoint localPoint = window2->mapFromGlobal(globalPoint);
 
     QPoint pixelDelta;
 
@@ -709,24 +711,28 @@ int QWasmEventTranslator::handleTouch(int eventType, const EmscriptenTouchEvent
 
         const EmscriptenTouchPoint *touches = &touchEvent->touches[i];
 
-        QPoint point(touches->targetX, touches->targetY);
+        QPoint targetPoint(touches->targetX, touches->targetY);
-        window2 = this->screen()->compositor()->windowAt(point, 5);
+        QPoint globalPoint = screen()->geometry().topLeft() + targetPoint;
+
+        window2 = this->screen()->compositor()->windowAt(globalPoint, 5);
+        if (window2 == nullptr)
+            continue;
+
         QWindowSystemInterface::TouchPoint touchPoint;
 
         touchPoint.area = QRect(0, 0, 8, 8);
         touchPoint.id = touches->identifier;
         touchPoint.pressure = 1.0;
 
-        const QPointF screenPos(point);
+        touchPoint.area.moveCenter(globalPoint);
-
-        touchPoint.area.moveCenter(screenPos);
 
         const auto tp = pressedTouchIds.constFind(touchPoint.id);
         if (tp != pressedTouchIds.constEnd())
             touchPoint.normalPosition = tp.value();
 
-        QPointF normalPosition(screenPos.x() / window2->width(),
+        QPointF localPoint = QPointF(window2->mapFromGlobal(globalPoint));
-                               screenPos.y() / window2->height());
+        QPointF normalPosition(localPoint.x() / window2->width(),
+                               localPoint.y() / window2->height());
 
         const bool stationaryTouchPoint = (normalPosition == touchPoint.normalPosition);
         touchPoint.normalPosition = normalPosition;