Draft: add parameter observer

To avoid having to restart FreeCAD after changing parameters.

src/Mod/Draft/CMakeLists.txt

@@ -71,6 +71,7 @@ SET(Draft_utilities
     draftutils/groups.py
     draftutils/init_tools.py
     draftutils/init_draft_statusbar.py
+    draftutils/params.py
     draftutils/units.py
     draftutils/utils.py
     draftutils/gui_utils.py

src/Mod/Draft/InitGui.py

@@ -132,6 +132,8 @@ class DraftWorkbench(FreeCADGui.Workbench):
         # Set up preferences pages
         if hasattr(FreeCADGui, "draftToolBar"):
             if not hasattr(FreeCADGui.draftToolBar, "loadedPreferences"):
+                from draftutils import params
+                params._param_observer_start()
                 FreeCADGui.addPreferencePage(":/ui/preferences-draft.ui", QT_TRANSLATE_NOOP("QObject", "Draft"))
                 FreeCADGui.addPreferencePage(":/ui/preferences-draftinterface.ui", QT_TRANSLATE_NOOP("QObject", "Draft"))
                 FreeCADGui.addPreferencePage(":/ui/preferences-draftsnap.ui", QT_TRANSLATE_NOOP("QObject", "Draft"))

src/Mod/Draft/draftutils/params.py

@@ -0,0 +1,121 @@
+# ***************************************************************************
+# *   Copyright (c) 2023 FreeCAD Project Association                        *
+# *                                                                         *
+# *   This program is free software; you can redistribute it and/or modify  *
+# *   it under the terms of the GNU Lesser General Public License (LGPL)    *
+# *   as published by the Free Software Foundation; either version 2 of     *
+# *   the License, or (at your option) any later version.                   *
+# *   for detail see the LICENCE text file.                                 *
+# *                                                                         *
+# *   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 Library General Public License for more details.                  *
+# *                                                                         *
+# *   You should have received a copy of the GNU Library General Public     *
+# *   License along with this program; if not, write to the Free Software   *
+# *   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  *
+# *   USA                                                                   *
+# *                                                                         *
+# ***************************************************************************
+
+""" Contains a parameter observer class and several related functions."""
+
+import FreeCAD as App
+import FreeCADGui as Gui
+from PySide import QtGui
+
+from draftutils import init_draft_statusbar
+from draftutils import utils
+from draftutils.translate import translate
+from draftviewproviders import view_base
+
+class ParamObserver:
+
+    def slotParamChanged(self, param, tp, name, value):
+        if name in ("gridBorder", "gridShowHuman", "coloredGridAxes", "gridEvery",
+                    "gridSpacing", "gridSize", "gridTransparency", "gridColor"):
+            _param_observer_callback_grid()
+            return
+        if name in ("DisplayStatusbarSnapWidget", "DisplayStatusbarScaleWidget"):
+            _param_observer_callback_statusbar()
+            return
+        if name == "snapStyle":
+            _param_observer_callback_snapstyle()
+            return
+        if name == "snapcolor":
+            _param_observer_callback_snapcolor()
+            return
+        if name == "patternFile":
+            _param_observer_callback_svg_pattern()
+            return
+
+
+def _param_observer_callback_grid():
+    if hasattr(App, "draft_working_planes") and hasattr(Gui, "Snapper"):
+        try:
+            trackers = Gui.Snapper.trackers
+            for wp in App.draft_working_planes[1]:
+                view = wp._view
+                if view in trackers[0]:
+                    i = trackers[0].index(view)
+                    grid = trackers[1][i]
+                    grid.pts = []
+                    grid.reset()
+                    grid.displayHumanFigure(wp)
+                    grid.setAxesColor(wp)
+        except Exception:
+            pass
+
+
+def _param_observer_callback_statusbar():
+    init_draft_statusbar.hide_draft_statusbar()
+    init_draft_statusbar.show_draft_statusbar()
+
+
+def _param_observer_callback_snapstyle():
+    if hasattr(Gui, "Snapper"):
+        Gui.Snapper.set_snap_style()
+
+
+def _param_observer_callback_snapcolor():
+    if hasattr(Gui, "Snapper"):
+        for snap_track in Gui.Snapper.trackers[2]:
+            snap_track.setColor()
+
+
+def _param_observer_callback_svg_pattern():
+    utils.load_svg_patterns()
+    if App.ActiveDocument is None:
+        return
+    msg = translate("draft", """Do you want to update the SVG pattern options
+of existing objects in all opened documents?""")
+    res = QtGui.QMessageBox.question(None, "Update SVG patterns", msg,
+                                     QtGui.QMessageBox.Yes | QtGui.QMessageBox.No,
+                                     QtGui.QMessageBox.No)
+    if res == QtGui.QMessageBox.No:
+        return
+    pats = list(utils.svg_patterns())
+    pats.sort()
+    pats = ["None"] + pats
+    for doc in App.listDocuments().values():
+        doc.openTransaction("SVG pattern update")
+        for obj in doc.Objects:
+            if hasattr(obj, "ViewObject") \
+                    and hasattr(obj.ViewObject, "Pattern") \
+                    and hasattr(obj.ViewObject, "Proxy") \
+                    and isinstance(obj.ViewObject.Proxy, view_base.ViewProviderDraft):
+                vobj = obj.ViewObject
+                old = vobj.Pattern
+                if old in pats:
+                    vobj.Pattern = pats
+                else:
+                    tmp_pats = [old] + pats[1:]
+                    tmp_pats.sort()
+                    vobj.Pattern = ["None"] + tmp_pats
+                vobj.Pattern = old
+        doc.commitTransaction()
+
+
+def _param_observer_start(param = App.ParamGet("User parameter:BaseApp/Preferences/Mod/Draft")):
+    param.AttachManager(ParamObserver())