Fix HiDPI support on non-touch devices

client/webgl_listeners.js

@@ -50,7 +50,7 @@ function mousedown(e, state, context) {
         return;
     }
 
-    const screenp = {'x': e.clientX, 'y': e.clientY};
+    const screenp = {'x': window.devicePixelRatio * e.clientX, 'y': window.devicePixelRatio * e.clientY};
     const canvasp = screen_to_canvas(state, screenp);
 
     clear_dynamic_stroke(state, context, state.me);
@@ -71,7 +71,7 @@ function mousemove(e, state, context) {
         do_draw = true;
     }
 
-    const screenp = {'x': e.clientX, 'y': e.clientY};
+    const screenp = {'x': window.devicePixelRatio * e.clientX, 'y': window.devicePixelRatio * e.clientY};
     const canvasp = screen_to_canvas(state, screenp);
 
     state.cursor = screenp;
@@ -121,7 +121,7 @@ function mouseup(e, state, context) {
 }
 
 function wheel(e, state, context) {
-    const screenp = {'x': e.clientX, 'y': e.clientY};
+    const screenp = {'x': window.devicePixelRatio * e.clientX, 'y': window.devicePixelRatio * e.clientY};
     const canvasp = screen_to_canvas(state, screenp);
 
     const dz = (e.deltaY < 0 ? 0.1 : -0.1);