Add Qt5 backwards compatibility for UI generation (#303)

Attempts to fully support PyQt5 backwards compatibility based on feedback from @PrentissLiu

morph/readability_settings_ui.py

@@ -6,7 +6,12 @@
 # run again.  Do not edit this file unless you know what you are doing.
 
 
-from PyQt6 import QtCore, QtWidgets
+try:
+    from PyQt6 import QtCore, QtGui, QtWidgets
+except:
+    from PyQt5 import QtCore, QtGui, QtWidgets
+    QtCore.Qt.AlignmentFlag.AlignLeading = QtCore.Qt.AlignLeading
+    QtCore.Qt.AlignmentFlag.AlignTrailing = QtCore.Qt.AlignTrailing
 
 
 class Ui_ReadabilitySettingsDialog(object):

morph/readability_ui.py

@@ -6,7 +6,12 @@
 # run again.  Do not edit this file unless you know what you are doing.
 
 
-from PyQt6 import QtCore, QtGui, QtWidgets
+try:
+    from PyQt6 import QtCore, QtGui, QtWidgets
+except:
+    from PyQt5 import QtCore, QtGui, QtWidgets
+    QtCore.Qt.AlignmentFlag.AlignLeading = QtCore.Qt.AlignLeading
+    QtCore.Qt.AlignmentFlag.AlignTrailing = QtCore.Qt.AlignTrailing
 
 
 class Ui_ReadabilityDialog(object):

scripts/build_ui.py

@@ -1,14 +1,21 @@
 import subprocess
 
-
 def build_ui(in_file, out_file):
-    stdout = subprocess.run(["pyuic6", in_file], stdout=subprocess.PIPE).stdout
-
-    lines = stdout.decode("utf-8").replace("__relpath__", "")
-
-    with open(out_file, "w") as sources:
-        sources.write(lines)
+    stdout = subprocess.Popen(["pyuic6", in_file], stdout=subprocess.PIPE, text=True).stdout
 
+    with open(out_file, 'w') as sources:
+        for line in iter(stdout.readline, ""):
+            if line.startswith("from PyQt6 import"):
+                imports = line.split("import")[1].strip()
+                sources.write(f"""try:
+    from PyQt6 import {imports}
+except:
+    from PyQt5 import {imports}
+    QtCore.Qt.AlignmentFlag.AlignLeading = QtCore.Qt.AlignLeading
+    QtCore.Qt.AlignmentFlag.AlignTrailing = QtCore.Qt.AlignTrailing
+""")
+            else:
+                sources.write(line)
 
 build_ui("morph/readability.ui", "morph/readability_ui.py")
 build_ui("morph/readability_settings.ui", "morph/readability_settings_ui.py")