wasm: ensure cursor reverts after window resize

This partially reverts 97be0cca17
but without the crash

We temporarily override the wasm cursor while leaving the
application/window cursor alone to mimic what desktop application
behavior is like.

Pick-to: 6.3
Fixes: QTBUG-99111
Change-Id: I23df48b2eaa82830593f1753ec23d14fe375b70c
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

src/plugins/platforms/wasm/qwasmcursor.cpp

@@ -47,7 +47,6 @@ void QWasmCursor::changeCursor(QCursor *windowCursor, QWindow *window)
     if (!screen)
         return;
 
-    QByteArray htmlCursorName;
     if (windowCursor) {
 
         // Bitmap and custom cursors are not implemented (will fall back to "auto")
@@ -60,10 +59,7 @@ void QWasmCursor::changeCursor(QCursor *windowCursor, QWindow *window)
     if (htmlCursorName.isEmpty())
         htmlCursorName = "default";
 
-    // Set cursor on the canvas
-    val canvas = QWasmScreen::get(screen)->canvas();
-    val canvasStyle = canvas["style"];
-    canvasStyle.set("cursor", val(htmlCursorName.constData()));
+    setWasmCursor(screen, htmlCursorName);
 }
 
 QByteArray QWasmCursor::cursorShapeToHtml(Qt::CursorShape shape)
@@ -143,3 +139,23 @@ QByteArray QWasmCursor::cursorShapeToHtml(Qt::CursorShape shape)
 
     return cursorName;
 }
+
+void QWasmCursor::setWasmCursor(QScreen *screen, const QByteArray &name)
+{
+    // Set cursor on the canvas
+    val canvas = QWasmScreen::get(screen)->canvas();
+    val canvasStyle = canvas["style"];
+    canvasStyle.set("cursor", val(name.constData()));
+}
+
+void QWasmCursor::setOverrideWasmCursor(QCursor *windowCursor, QScreen *screen)
+{
+    QWasmCursor *wCursor = static_cast<QWasmCursor *>(QWasmScreen::get(screen)->cursor());
+    wCursor->setWasmCursor(screen, wCursor->cursorShapeToHtml(windowCursor->shape()));
+}
+
+void QWasmCursor::clearOverrideWasmCursor(QScreen *screen)
+{
+    QWasmCursor *wCursor = static_cast<QWasmCursor *>(QWasmScreen::get(screen)->cursor());
+    wCursor->setWasmCursor(screen, wCursor->htmlCursorName);
+}

src/plugins/platforms/wasm/qwasmcursor.h

@@ -38,6 +38,11 @@ public:
     void changeCursor(QCursor *windowCursor, QWindow *window) override;
 
     QByteArray cursorShapeToHtml(Qt::CursorShape shape);
+    static void setOverrideWasmCursor(QCursor *windowCursor, QScreen *screen);
+    static void clearOverrideWasmCursor(QScreen *screen);
+private:
+    QByteArray htmlCursorName;
+    void setWasmCursor(QScreen *screen, const QByteArray &name);
 };
 
 #endif

src/plugins/platforms/wasm/qwasmeventtranslator.cpp

@@ -33,7 +33,7 @@
 #include "qwasmintegration.h"
 #include "qwasmclipboard.h"
 #include "qwasmstring.h"
-
+#include "qwasmcursor.h"
 #include <QtGui/qevent.h>
 #include <qpa/qwindowsysteminterface.h>
 #include <QtCore/qcoreapplication.h>
@@ -499,7 +499,7 @@ bool QWasmEventTranslator::processMouse(int eventType, const EmscriptenMouseEven
             pressedWindow = nullptr;
         }
 
-        if (mouseEvent->button == 0) {
+       if (draggedWindow && pressedButtons.testFlag(Qt::NoButton)) {
             draggedWindow = nullptr;
             resizeMode = QWasmWindow::ResizeNone;
         }
@@ -514,8 +514,22 @@ bool QWasmEventTranslator::processMouse(int eventType, const EmscriptenMouseEven
     {
         buttonEventType = QEvent::MouseMove;
 
-        if (htmlWindow && htmlWindow->isPointOnResizeRegion(globalPoint))
-            window2->setCursor(cursorForMode(htmlWindow->resizeModeAtPoint(globalPoint)));
+        if (htmlWindow && pressedButtons.testFlag(Qt::NoButton)) {
+
+            if (htmlWindow->isPointOnResizeRegion(globalPoint)) {
+                QCursor resizingCursor = cursorForMode(htmlWindow->resizeModeAtPoint(globalPoint));
+
+                if (resizingCursor != window2->cursor()) {
+                    isCursorOverridden = true;
+                    QWasmCursor::setOverrideWasmCursor(&resizingCursor, window2->screen());
+                }
+            } else { // off resizing area
+                if (isCursorOverridden) {
+                    isCursorOverridden = false;
+                    QWasmCursor::clearOverrideWasmCursor(window2->screen());
+                }
+            }
+        }
 
         if (!(htmlWindow->m_windowState & Qt::WindowFullScreen) && !(htmlWindow->m_windowState & Qt::WindowMaximized)) {
             if (resizeMode == QWasmWindow::ResizeNone && draggedWindow) {

src/plugins/platforms/wasm/qwasmeventtranslator.h

@@ -100,6 +100,8 @@ private:
     Qt::Key m_emDeadKey = Qt::Key_unknown;
     bool m_emStickyDeadKey = false;
     QCursor cursorForMode(QWasmWindow::ResizeMode mode);
+    QCursor overriddenCursor;
+    bool isCursorOverridden = false;
 };
 
 QT_END_NAMESPACE