Flip screen-info script to qt6, refine it to heck.

Buncha updates and improvements,
- adjust sub-namespace imports according to console warnings.
- iterate all detected screens in a loop and instead report which is the
  primary and the current.
- type annotate all vars where non-obvious, particularly the`Qt` refs.

snippets/qt_screen_info.py

@@ -1,4 +1,22 @@
-"""
+# piker: trading gear for hackers
+# Copyright (C) Tyler Goodlet (in stewardship for pikers)
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the GNU Affero General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+
+# This program is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU Affero General Public License for more details.
+
+# You should have received a copy of the GNU Affero General Public License
+# along with this program.  If not, see <https://www.gnu.org/licenses/>.
+
+'''
+A per-display, DPI (scaling) info dumper.
+
 Resource list for mucking with DPIs on multiple screens:
 
 - https://stackoverflow.com/questions/42141354/convert-pixel-size-to-point-size-for-fonts-on-multiple-platforms
@@ -12,89 +30,86 @@ Resource list for mucking with DPIs on multiple screens:
 - https://stackoverflow.com/questions/16561879/what-is-the-difference-between-logicaldpix-and-physicaldpix-in-qt
 - https://doc.qt.io/qt-5/qguiapplication.html#screenAt
 
-"""
+'''
 
 from pyqtgraph import QtGui
-from PyQt5.QtCore import (
+from PyQt6 import (
-     Qt, QCoreApplication
+    QtCore,
+    QtWidgets,
+)
+from PyQt6.QtCore import (
+    Qt,
+    QCoreApplication,
+    QSize,
+    QRect,
 )
 
 # Proper high DPI scaling is available in Qt >= 5.6.0. This attibute
 # must be set before creating the application
 if hasattr(Qt, 'AA_EnableHighDpiScaling'):
-    QCoreApplication.setAttribute(Qt.AA_EnableHighDpiScaling, True)
+    QCoreApplication.setAttribute(
+        Qt.AA_EnableHighDpiScaling,
+        True,
+    )
 
 if hasattr(Qt, 'AA_UseHighDpiPixmaps'):
-    QCoreApplication.setAttribute(Qt.AA_UseHighDpiPixmaps, True)
+    QCoreApplication.setAttribute(
+        Qt.AA_UseHighDpiPixmaps,
+        True,
+    )
 
-
+app = QtWidgets.QApplication([])
-app = QtGui.QApplication([])
+window = QtWidgets.QMainWindow()
-window = QtGui.QMainWindow()
+main_widget = QtWidgets.QWidget()
-main_widget = QtGui.QWidget()
 window.setCentralWidget(main_widget)
 window.show()
 
-pxr = main_widget.devicePixelRatioF()
+pxr: float = main_widget.devicePixelRatioF()
 
-# screen_num = app.desktop().screenNumber()
+# explicitly get main widget and primary displays
-# screen = app.screens()[screen_num]
+current_screen: QtGui.QScreen = app.screenAt(
+    main_widget.geometry().center()
+)
+primary_screen: QtGui.QScreen = app.primaryScreen()
 
-screen = app.screenAt(main_widget.geometry().center())
+screen: QtGui.QScreen
-
+for screen in app.screens():
-name = screen.name()
+    name: str = screen.name()
-size = screen.size()
+    model: str = screen.model().rstrip()
-geo = screen.availableGeometry()
+    size: QSize = screen.size()
-phydpi = screen.physicalDotsPerInch()
+    geo: QRect = screen.availableGeometry()
-logdpi = screen.logicalDotsPerInch()
+    phydpi: float = screen.physicalDotsPerInch()
+    logdpi: float = screen.logicalDotsPerInch()
+    is_primary: bool = screen is primary_screen
+    is_current: bool = screen is current_screen
 
     print(
-    # f'screen number: {screen_num}\n',
+        f'------ screen name: {name} ------\n'
-    f'screen name: {name}\n'
+        f'|_primary: {is_primary}\n'
-    f'screen size: {size}\n'
+        f' _current: {is_current}\n'
-    f'screen geometry: {geo}\n\n'
+        f' _model: {model}\n'
-    f'devicePixelRationF(): {pxr}\n'
+        f' _screen size: {size}\n'
-    f'physical dpi: {phydpi}\n'
+        f' _screen geometry: {geo}\n'
-    f'logical dpi: {logdpi}\n'
+        f' _devicePixelRationF(): {pxr}\n'
+        f' _physical dpi: {phydpi}\n'
+        f' _logical dpi: {logdpi}\n'
     )
 
-print('-'*50)
+# app-wide font info
-
-screen = app.primaryScreen()
-
-name = screen.name()
-size = screen.size()
-geo = screen.availableGeometry()
-phydpi = screen.physicalDotsPerInch()
-logdpi = screen.logicalDotsPerInch()
-
-print(
-    # f'screen number: {screen_num}\n',
-    f'screen name: {name}\n'
-    f'screen size: {size}\n'
-    f'screen geometry: {geo}\n\n'
-    f'devicePixelRationF(): {pxr}\n'
-    f'physical dpi: {phydpi}\n'
-    f'logical dpi: {logdpi}\n'
-)
-
-
-# app-wide font
 font = QtGui.QFont("Hack")
 # use pixel size to be cross-resolution compatible?
 font.setPixelSize(6)
 
-
 fm = QtGui.QFontMetrics(font)
-fontdpi = fm.fontDpi()
+fontdpi: float = fm.fontDpi()
-font_h = fm.height()
+font_h: int = fm.height()
-
-string = '10000'
-str_br = fm.boundingRect(string)
-str_w = str_br.width()
 
+string: str = '10000'
+str_br: QtCore.QRect = fm.boundingRect(string)
+str_w: int = str_br.width()
 
 print(
-    # f'screen number: {screen_num}\n',
+    f'------ global font settings ------\n'
     f'font dpi: {fontdpi}\n'
     f'font height: {font_h}\n'
     f'string bounding rect: {str_br}\n'