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.

Change-Id: I38abb2a191076ea04581c29552657ee3e0b87dbc
Reviewed-by: Morten Johan Sørvig <morten.sorvig@qt.io>

1 files changed, 2 insertions, 2 deletions

diff --git a/src/plugins/platforms/wasm/qwasmscreen.cpp b/src/plugins/platforms/wasm/qwasmscreen.cpp
index d407111c2f..2788f1ac19 100644
--- a/src/plugins/platforms/wasm/qwasmscreen.cpp
+++ b/src/plugins/platforms/wasm/qwasmscreen.cpp
@@ -178,10 +178,10 @@ 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();