wasm: support setting the font DPI from JS

We have not really been able to determine what the
default DPI should be, so make it configurable with
API on qtloader.js:

  qtLoader.setFontDpi(72);

Also lowers the default DPI to the standard value of
96 (down from Qt default 100).

Task-number: QTBUG-75510
Change-Id: Ica1164c8d80bb06519233adebf2c9e400c0991ce
Reviewed-by: Tor Arne Vestbø <tor.arne.vestbo@qt.io>

1 files changed, 14 insertions, 0 deletions

diff --git a/src/plugins/platforms/wasm/qtloader.js b/src/plugins/platforms/wasm/qtloader.js
index 4752a1dcee..ef4a6ec2b9 100644
--- a/src/plugins/platforms/wasm/qtloader.js
+++ b/src/plugins/platforms/wasm/qtloader.js
@@ -124,6 +124,8 @@
 //      Remove canvas at run-time. Removes the corresponding QScreen.
 // resizeCanvasElement
 //      Signals to the application that a canvas has been resized.
+// setFontDpi
+//      Sets the logical font dpi for the application.
 
 
 var Module = {}
@@ -237,6 +239,8 @@ function QtLoader(config)
     publicAPI.addCanvasElement = addCanvasElement;
     publicAPI.removeCanvasElement = removeCanvasElement;
     publicAPI.resizeCanvasElement = resizeCanvasElement;
+    publicAPI.setFontDpi = setFontDpi;
+    publicAPI.fontDpi = fontDpi;
 
     restartCount = 0;
 
@@ -557,6 +561,16 @@ function QtLoader(config)
             Module.qtResizeCanvasElement(element);
     }
 
+    function setFontDpi(dpi) {
+        Module.qtFontDpi = dpi;
+        if (publicAPI.status == "Running")
+            Module.qtSetFontDpi(dpi);
+    }
+
+    function fontDpi() {
+        return Module.qtFontDpi;
+    }
+
     setStatus("Created");
 
     return publicAPI;