1 files changed, 49 insertions, 2 deletions

diff --git a/src/plugins/platforms/wasm/qwasmscreen.cpp b/src/plugins/platforms/wasm/qwasmscreen.cpp
index 42ca608da1..4c67e3c799 100644
--- a/src/plugins/platforms/wasm/qwasmscreen.cpp
+++ b/src/plugins/platforms/wasm/qwasmscreen.cpp
@@ -20,6 +20,8 @@
 #include <QtGui/qguiapplication.h>
 #include <private/qhighdpiscaling_p.h>
 
+#include <tuple>
+
 QT_BEGIN_NAMESPACE
 
 using namespace emscripten;
@@ -42,7 +44,7 @@ QWasmScreen::QWasmScreen(const emscripten::val &containerOrCanvas)
         // Create the canvas (for the correct document) as a child of the container
         m_canvas = containerOrCanvas["ownerDocument"].call<emscripten::val>("createElement", std::string("canvas"));
         containerOrCanvas.call<void>("appendChild", m_canvas);
-        std::string screenId = std::string("qtcanvas_") + std::to_string(uint32_t(this));
+        std::string screenId = std::string("qtcanvas_") + std::to_string(uintptr_t(this));
         m_canvas.set("id", screenId);
 
         // Make the canvas occupy 100% of parent
@@ -166,13 +168,49 @@ std::string QWasmScreen::canvasSpecialHtmlTargetId() const
 {
     // Return a globally unique id for the canvas. We can choose any string,
     // as long as it starts with a "!".
-    return std::string("!qtcanvas_") + std::to_string(uint32_t(this));
+    return std::string("!qtcanvas_") + std::to_string(uintptr_t(this));
+}
+
+namespace {
+
+// Compare Emscripten versions, returns > 0 if a is greater than b.
+
+int compareVersionComponents(int a, int b)
+{
+    return a >= 0 && b >= 0 ? a - b : 0;
+}
+
+int compareEmscriptenVersions(std::tuple<int, int, int> a, std::tuple<int, int, int> b)
+{
+    if (std::get<0>(a) == std::get<0>(b)) {
+        if (std::get<1>(a) == std::get<1>(b)) {
+            return compareVersionComponents(std::get<2>(a), std::get<2>(b));
+        }
+        return compareVersionComponents(std::get<1>(a), std::get<1>(b));
+    }
+    return compareVersionComponents(std::get<0>(a), std::get<0>(b));
 }
 
+bool isEmsdkVersionGreaterThan(std::tuple<int, int, int> test)
+{
+    return compareEmscriptenVersions(
+        std::make_tuple(__EMSCRIPTEN_major__, __EMSCRIPTEN_minor__, __EMSCRIPTEN_tiny__), test) > 0;
+}
+
+} // namespace
+
 bool QWasmScreen::hasSpecialHtmlTargets() const
 {
     static bool gotIt = []{
         // Enable use of specialHTMLTargets, if available
+
+        // On Emscripten > 3.1.14 (exact version not known), emscripten::val::module_property()
+        // aborts instead of returning undefined when attempting to resolve the specialHTMLTargets
+        // property, in the case where it is not defined. Disable the availability test in this case.
+        // FIXME: Add alternative way to enable.
+        if (isEmsdkVersionGreaterThan(std::make_tuple(3, 1, 14)))
+            return false;
+
         emscripten::val htmlTargets = emscripten::val::module_property("specialHTMLTargets");
         if (htmlTargets.isUndefined())
             return false;
@@ -258,6 +296,15 @@ QWindow *QWasmScreen::topLevelAt(const QPoint &p) const
     return m_compositor->windowAt(p);
 }
 
+QPoint QWasmScreen::translateAndClipGlobalPoint(const QPoint &p) const
+{
+    return QPoint(
+            std::max(screen()->geometry().left(),
+                     std::min(screen()->geometry().right(), screen()->geometry().left() + p.x())),
+            std::max(screen()->geometry().top(),
+                     std::min(screen()->geometry().bottom(), screen()->geometry().top() + p.y())));
+}
+
 void QWasmScreen::invalidateSize()
 {
     m_geometry = QRect();