wasm: Specify event targets by CSS selectors; Support emsdk >= 1.39.5

DISABLE_DEPRECATED_FIND_EVENT_TARGET_BEHAVIOR is now on by default, which
means that functions like emscripten_set_keydown_callback() now expects
CSS selectors (e.g. "#canvas_id" instead of "canvas_id").

In addition, Module.canvas is no more. Add a deprecation warning in case
someone is setting it and expects Qt to use it. (qtloader.js sets
qtCanvasElements instead).

This bumps the minimum supported emsdk version to 1.39.5.

Fixes: QTBUG-74601
Change-Id: I8c46ce170143f969e6281824f78b1bb809c267ab
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>

4 files changed, 21 insertions, 20 deletions

diff --git a/src/plugins/platforms/wasm/qwasmeventtranslator.cpp b/src/plugins/platforms/wasm/qwasmeventtranslator.cpp
index d99c202c48..62ada796db 100644
--- a/src/plugins/platforms/wasm/qwasmeventtranslator.cpp
+++ b/src/plugins/platforms/wasm/qwasmeventtranslator.cpp
@@ -339,8 +339,7 @@ QWasmEventTranslator::QWasmEventTranslator(QWasmScreen *screen)
 
 void QWasmEventTranslator::initEventHandlers()
 {
-    QByteArray _canvasId = screen()->canvasId().toUtf8();
-    const char *canvasId = _canvasId.constData();
+    QByteArray canvasSelector = "#" + screen()->canvasId().toUtf8();
 
     // The Platform Detect: expand coverage and move as needed
     enum Platform {
@@ -364,21 +363,21 @@ void QWasmEventTranslator::initEventHandlers()
         }
     }
 
-    emscripten_set_keydown_callback(canvasId, (void *)this, 1, &keyboard_cb);
-    emscripten_set_keyup_callback(canvasId, (void *)this, 1, &keyboard_cb);
+    emscripten_set_keydown_callback(canvasSelector.constData(), (void *)this, 1, &keyboard_cb);
+    emscripten_set_keyup_callback(canvasSelector.constData(), (void *)this, 1, &keyboard_cb);
 
-    emscripten_set_mousedown_callback(canvasId, (void *)this, 1, &mouse_cb);
-    emscripten_set_mouseup_callback(canvasId, (void *)this, 1, &mouse_cb);
-    emscripten_set_mousemove_callback(canvasId, (void *)this, 1, &mouse_cb);
+    emscripten_set_mousedown_callback(canvasSelector.constData(), (void *)this, 1, &mouse_cb);
+    emscripten_set_mouseup_callback(canvasSelector.constData(), (void *)this, 1, &mouse_cb);
+    emscripten_set_mousemove_callback(canvasSelector.constData(), (void *)this, 1, &mouse_cb);
 
-    emscripten_set_focus_callback(canvasId, (void *)this, 1, &focus_cb);
+    emscripten_set_focus_callback(canvasSelector.constData(), (void *)this, 1, &focus_cb);
 
-    emscripten_set_wheel_callback(canvasId, (void *)this, 1, &wheel_cb);
+    emscripten_set_wheel_callback(canvasSelector.constData(), (void *)this, 1, &wheel_cb);
 
-    emscripten_set_touchstart_callback(canvasId, (void *)this, 1, &touchCallback);
-    emscripten_set_touchend_callback(canvasId, (void *)this, 1, &touchCallback);
-    emscripten_set_touchmove_callback(canvasId, (void *)this, 1, &touchCallback);
-    emscripten_set_touchcancel_callback(canvasId, (void *)this, 1, &touchCallback);
+    emscripten_set_touchstart_callback(canvasSelector.constData(), (void *)this, 1, &touchCallback);
+    emscripten_set_touchend_callback(canvasSelector.constData(), (void *)this, 1, &touchCallback);
+    emscripten_set_touchmove_callback(canvasSelector.constData(), (void *)this, 1, &touchCallback);
+    emscripten_set_touchcancel_callback(canvasSelector.constData(), (void *)this, 1, &touchCallback);
 }
 
 template <typename Event>
diff --git a/src/plugins/platforms/wasm/qwasmintegration.cpp b/src/plugins/platforms/wasm/qwasmintegration.cpp
index ee3f6afb73..9934f5ac19 100644
--- a/src/plugins/platforms/wasm/qwasmintegration.cpp
+++ b/src/plugins/platforms/wasm/qwasmintegration.cpp
@@ -108,9 +108,8 @@ QWasmIntegration::QWasmIntegration()
     s_instance = this;
 
     // We expect that qtloader.js has populated Module.qtCanvasElements with one or more canvases.
-    // Also check Module.canvas, which may be set if the emscripen or a custom loader is used.
     emscripten::val qtCanvaseElements = val::module_property("qtCanvasElements");
-    emscripten::val canvas = val::module_property("canvas");
+    emscripten::val canvas = val::module_property("canvas"); // TODO: remove for Qt 6.0
 
     if (!qtCanvaseElements.isUndefined()) {
         int screenCount = qtCanvaseElements["length"].as<int>();
@@ -119,7 +118,9 @@ QWasmIntegration::QWasmIntegration()
             QString canvasId = QWasmString::toQString(canvas["id"]);
             addScreen(canvasId);
         }
-    } else if (!canvas.isUndefined()){
+    } else if (!canvas.isUndefined()) {
+        qWarning() << "Module.canvas is deprecated. A future version of Qt will stop reading this property. "
+                   << "Instead, set Module.qtCanvasElements to be an array of canvas elements, or use qtloader.js.";
         QString canvasId = QWasmString::toQString(canvas["id"]);
         addScreen(canvasId);
     }
@@ -139,7 +140,7 @@ QWasmIntegration::QWasmIntegration()
             integration->resizeAllScreens();
         return 0;
     };
-    emscripten_set_resize_callback(nullptr, nullptr, 1, onWindowResize);
+    emscripten_set_resize_callback(EMSCRIPTEN_EVENT_TARGET_WINDOW, nullptr, 1, onWindowResize);
 }
 
 QWasmIntegration::~QWasmIntegration()
diff --git a/src/plugins/platforms/wasm/qwasmopenglcontext.cpp b/src/plugins/platforms/wasm/qwasmopenglcontext.cpp
index 501ab99116..4ddd56fd8c 100644
--- a/src/plugins/platforms/wasm/qwasmopenglcontext.cpp
+++ b/src/plugins/platforms/wasm/qwasmopenglcontext.cpp
@@ -106,7 +106,8 @@ EMSCRIPTEN_WEBGL_CONTEXT_HANDLE QWasmOpenGLContext::createEmscriptenContext(cons
     attributes.depth = useDepthStencil;
     attributes.stencil = useDepthStencil;
 
-    EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context = emscripten_webgl_create_context(canvasId.toUtf8().constData(), &attributes);
+    QByteArray convasSelector = "#" + canvasId.toUtf8();
+    EMSCRIPTEN_WEBGL_CONTEXT_HANDLE context = emscripten_webgl_create_context(convasSelector.constData(), &attributes);
 
     return context;
 }
diff --git a/src/plugins/platforms/wasm/qwasmscreen.cpp b/src/plugins/platforms/wasm/qwasmscreen.cpp
index 5e6f94b9ed..ba14421255 100644
--- a/src/plugins/platforms/wasm/qwasmscreen.cpp
+++ b/src/plugins/platforms/wasm/qwasmscreen.cpp
@@ -180,10 +180,10 @@ void QWasmScreen::updateQScreenAndCanvasRenderSize()
     // Setting the render size to a value larger than the CSS size enables high-dpi
     // rendering.
 
-    QByteArray canvasId = m_canvasId.toUtf8();
+    QByteArray canvasSelector = "#" + m_canvasId.toUtf8();
     double css_width;
     double css_height;
-    emscripten_get_element_css_size(canvasId.constData(), &css_width, &css_height);
+    emscripten_get_element_css_size(canvasSelector.constData(), &css_width, &css_height);
     QSizeF cssSize(css_width, css_height);
 
     QSizeF canvasSize = cssSize * devicePixelRatio();