Qt and wx default to bitmap present

docs/backends.rst

@@ -192,14 +192,14 @@ But the other way around, running a Qt canvas in e.g. the trio loop, works fine:
 
 
 There are known issue with Qt widgets that render directly to screen (i.e. widgets that obtain ``widget.winId()``),
-related to how they interact with other widgets and in docks.
-If you encounter such issues, consider using the bitmap present-method. That way, the rendering happens
-off-screen, and is than provided to Qt as an image. This is a safer approach, albeit lowers the performance (FPS)
-somewhat when the render area is large.
+related to how they interact with other widgets and in docks. Therefore, the Qt backend defaults to the 'bitmap' present method.
+If high FPS is a big deal, you can easily set the present method to 'screen'. If you do this, be aware of possible problems,
+especially in some Linux environment and when the widget is in a QDockWidget.
 
 .. code-block:: py
 
-    widget = QRenderWidget(present_method="bitmap")
+    widget = QRenderWidget(present_method="bitmap")  # safe (default)
+    widget = QRenderWidget(present_method="screen")  # probably higher fps, but can cause problems
 
 
 Support for wx

rendercanvas/qt.py

@@ -14,7 +14,6 @@
 from .base import WrapperRenderCanvas, BaseCanvasGroup, BaseRenderCanvas, BaseLoop
 from ._coreutils import (
     logger,
-    SYSTEM_IS_WAYLAND,
     get_alt_x11_display,
     get_alt_wayland_display,
     select_qt_lib,
@@ -372,12 +371,13 @@ def _rc_gui_poll(self):
     def _rc_get_present_info(self, present_methods):
         # Select the method
         the_method = present_methods[0]
-        if SYSTEM_IS_WAYLAND and "bitmap" in present_methods:
-            # Trying to render to screen on Wayland segfaults. This might be because
-            # the "display" is not the real display id. We can tell Qt to use
-            # XWayland, so we can use the X11 path. This worked at some point,
-            # but later this resulted in a Rust panic. So, until this is sorted
-            # out, we fall back to rendering via an image.
+        if "bitmap" in present_methods:
+            # There are various known problems with rendering to screen on Qt.
+            # Some relate to getting a wgpu surface, and Qt not able to provide a display-id on Linux.
+            # Some relate to Qt simply not liking it when an application bypasses Qt's compositing.
+            # For an overview see: https://github.com/pygfx/wgpu-py/issues/688
+            # To avoid problems, and be consistent, Qt defaults to 'bitmap' present.
+            # In cases where the extra performance of 'screen' present mode matters, ppl can easily override it.
             the_method = "bitmap"
 
         # Apply

rendercanvas/wx.py

@@ -14,7 +14,6 @@
 
 from ._coreutils import (
     logger,
-    SYSTEM_IS_WAYLAND,
     get_alt_x11_display,
     get_alt_wayland_display,
 )
@@ -287,8 +286,9 @@ def _rc_gui_poll(self):
     def _rc_get_present_info(self, present_methods):
         # Select method
         the_method = present_methods[0]
-        if SYSTEM_IS_WAYLAND and "bitmap" in present_methods:
-            the_method = "bitmap"  # also see qt.py
+        if "bitmap" in present_methods:
+            # Default to 'bitmap', also see note in qt.py
+            the_method = "bitmap"
 
         # Apply
         if the_method == "screen":