the scaling issue is from VisPy, removing the previous changes on this subject and adding a patch until the new release of VisPy

CHANGELOG.md

@@ -11,7 +11,8 @@ CHANGELOG for FlatCAM beta
 
 - using PyQt6 with multi monitors, when the pixel ratio (scaling in WIndows) is different than 1.0 there are visual issues in the 3D canvas - trying to solve by updating the dpi - partial solve
 - failing to load the 3d graphic engine is now reported on the log.txt file found in the Preferences folder (in appData/Roaming/app_name for Windows)
-- added an example to ilustrate the issue with scaling in Qt6 and VisPy
+- added an example to illustrate the issue with scaling in Qt6 and VisPy
+- the scaling issue is from VisPy, removing the previous changes on this subject and adding a patch until the new release of VisPy
 
 23.08.2021
 

Utils/vispy_example_pyqt6.py

@@ -2,7 +2,6 @@ from PyQt6.QtGui import QPalette, QScreen
 from PyQt6 import QtCore, QtWidgets
 
 import vispy.scene as scene
-from vispy.scene.visuals import Rectangle, Text
 from vispy.color import Color
 
 import sys
@@ -24,6 +23,7 @@ class VisPyCanvas(scene.SceneCanvas):
         self.central_widget.bgcolor = back_color
         self.central_widget.border_color = back_color
 
+        # Add a Grid Widget
         self.grid_widget = self.central_widget.add_grid(margin=10)
         self.grid_widget.spacing = 0
 
@@ -60,6 +60,7 @@ class VisPyCanvas(scene.SceneCanvas):
         self.xaxis.link_view(self.view)
         self.yaxis.link_view(self.view)
 
+        # add GridLines
         self.grid = scene.GridLines(parent=self.view.scene, color='dimgray')
         self.grid.set_gl_state(depth_test=False)
 
@@ -166,8 +167,15 @@ class MyGui(QtWidgets.QMainWindow):
         :param new_screen:  QtGui.QScreen where the app windows is located after move
         :return:
         """
+        try:
             old_pixel_ratio = old_screen.devicePixelRatio()
+        except AttributeError:
+            return
+
+        try:
             new_pixel_ratio = new_screen.devicePixelRatio()
+        except AttributeError:
+            return
 
         if old_pixel_ratio != new_pixel_ratio:
             # update canvas dpi

appGUI/MainGUI.py

@@ -49,7 +49,7 @@ class MainGUI(QtWidgets.QMainWindow):
     # Emitted when persistent window geometry needs to be retained
     geom_update = QtCore.pyqtSignal(int, int, int, int, int, name='geomUpdate')
     final_save = QtCore.pyqtSignal(name='saveBeforeExit')
-    screenChanged = QtCore.pyqtSignal(QtGui.QScreen, QtGui.QScreen)
+    # screenChanged = QtCore.pyqtSignal(QtGui.QScreen, QtGui.QScreen)
 
     # https://www.w3.org/TR/SVG11/types.html#ColorKeywords
     def __init__(self, app):
@@ -1988,23 +1988,23 @@ class MainGUI(QtWidgets.QMainWindow):
         self.infobar.setContextMenuPolicy(QtCore.Qt.ContextMenuPolicy.ActionsContextMenu)
         self.build_infobar_context_menu()
 
-        self.screenChanged.connect(self.on_screen_change)
+        # self.screenChanged.connect(self.on_screen_change)
 
-    def on_screen_change(self, old_screen, new_screen):
+    # def on_screen_change(self, old_screen, new_screen):
-        """
+    #     """
-        Handler of a signal that emits when screens are changed in a multi-monitor setup
+    #     Handler of a signal that emits when screens are changed in a multi-monitor setup
-
+    #
-        :param old_screen:  QtGui.QScreen where the app windows was located before move
+    #     :param old_screen:  QtGui.QScreen where the app windows was located before move
-        :param new_screen:  QtGui.QScreen where the app windows is located after move
+    #     :param new_screen:  QtGui.QScreen where the app windows is located after move
-        :return:
+    #     :return:
-        """
+    #     """
-        old_pixel_ratio = old_screen.devicePixelRatio()
+    #     old_pixel_ratio = old_screen.devicePixelRatio()
-        new_pixel_ratio = new_screen.devicePixelRatio()
+    #     new_pixel_ratio = new_screen.devicePixelRatio()
-
+    #
-        if old_pixel_ratio != 1.0 or new_pixel_ratio != 1.0:
+    #     if old_pixel_ratio != 1.0 or new_pixel_ratio != 1.0:
-            # update canvas dpi
+    #         # update canvas dpi
-            ratio = new_pixel_ratio / old_pixel_ratio
+    #         ratio = new_pixel_ratio / old_pixel_ratio
-            self.app.plotcanvas.dpi = self.app.plotcanvas.dpi * ratio
+    #         self.app.plotcanvas.dpi = self.app.plotcanvas.dpi * ratio
 
     def set_ui_title(self, name):
         """
@@ -4237,14 +4237,14 @@ class MainGUI(QtWidgets.QMainWindow):
                 # sys.exit(0)
         event.ignore()
 
-    def moveEvent(self, event):
+    # def moveEvent(self, event):
-        oldScreen = QtWidgets.QApplication.screenAt(event.oldPos())
+    #     oldScreen = QtWidgets.QApplication.screenAt(event.oldPos())
-        newScreen = QtWidgets.QApplication.screenAt(event.pos())
+    #     newScreen = QtWidgets.QApplication.screenAt(event.pos())
-
+    #
-        if not oldScreen == newScreen:
+    #     if not oldScreen == newScreen:
-            self.screenChanged.emit(oldScreen, newScreen)
+    #         self.screenChanged.emit(oldScreen, newScreen)
-
+    #
-        return super().moveEvent(event)
+    #     return super().moveEvent(event)
 
 
 class ShortcutsTab(QtWidgets.QWidget):

appGUI/VisPyPatches.py

@@ -7,6 +7,7 @@
 # ##########################################################
 
 from vispy.visuals import markers, InfiniteLineVisual
+from vispy.app.backends._pyqt6 import CanvasBackendDesktop
 from vispy.visuals.axis import Ticker, _get_ticks_talbot
 from vispy.scene.widgets import Grid
 import numpy as np
@@ -55,7 +56,7 @@ def apply_patches():
     Grid._prepare_draw = _prepare_draw
     Grid._update_clipper = _update_clipper
 
-    # Patch InfiniteLine visual to 1px width
+    # Patch InfiniteLine visual to 1.5px width
     def _prepare_draw(self, view=None):
         """This method is called immediately before each draw.
         The *view* argument indicates which view is about to be drawn.
@@ -72,7 +73,7 @@ def apply_patches():
 
         if GL:
             GL.glDisable(GL.GL_LINE_SMOOTH)
-            GL.glLineWidth(2.0)
+            GL.glLineWidth(1.5)
 
         if self._changed['pos']:
             self.pos_buf.set_data(self._pos)
@@ -139,3 +140,19 @@ def apply_patches():
             return NotImplementedError
 
     Ticker._get_tick_frac_labels = _get_tick_frac_labels
+
+    def _resizeGL(self, w, h):
+        if self._vispy_canvas is None:
+            return
+        if hasattr(self, 'devicePixelRatio'):
+            # We take into account devicePixelRatio, which is non-unity on
+            # e.g HiDPI displays.
+            # self.devicePixelRatio() is a float and should have been in Qt5 according to the documentation
+            ratio = self.devicePixelRatio()
+            w = int(w * ratio)
+            h = int(h * ratio)
+        self._vispy_set_physical_size(w, h)
+        self._vispy_canvas.events.resize(size=(self.width(), self.height()),
+                                         physical_size=(w, h))
+
+    CanvasBackendDesktop.resizeGL = _resizeGL