Allow disabling scroll sync

data/de.wolfvollprecht.UberWriter.gschema.xml

@@ -48,6 +48,13 @@
         It can cause performance problems to some users.
       </description>
     </key>
+    <key name='sync-scroll' type='b'>
+      <default>true</default>
+      <summary>Synchronize editor/preview scrolling</summary>
+      <description>
+        Keep the editor and preview scroll positions in sync.
+      </description>
+    </key>
     <key name='input-format' type='s'>
       <default>"markdown"</default>
       <summary>Input format</summary>

data/ui/Preferences.ui

@@ -138,11 +138,11 @@
               </packing>
             </child>
             <child>
-              <object class="GtkLabel" id="format_label">
+              <object class="GtkLabel" id="sync_scroll_label">
                 <property name="visible">True</property>
                 <property name="can_focus">False</property>
                 <property name="halign">start</property>
-                <property name="label" translatable="yes">Input format</property>
+                <property name="label" translatable="yes">Synchronize editor/preview scrolling</property>
                 <property name="justify">right</property>
               </object>
               <packing>
@@ -151,17 +151,29 @@
               </packing>
             </child>
             <child>
-              <object class="GtkButton" id="input_format_help_button">
+              <object class="GtkSwitch" id="sync_scroll_switch">
                 <property name="visible">True</property>
                 <property name="can_focus">True</property>
-                <property name="receives_default">False</property>
-                <property name="image">help</property>
+                <property name="halign">end</property>
               </object>
               <packing>
-                <property name="left_attach">1</property>
+                <property name="left_attach">2</property>
                 <property name="top_attach">4</property>
               </packing>
             </child>
+            <child>
+              <object class="GtkLabel" id="input_format_label">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="halign">start</property>
+                <property name="label" translatable="yes">Input format</property>
+                <property name="justify">right</property>
+              </object>
+              <packing>
+                <property name="left_attach">0</property>
+                <property name="top_attach">5</property>
+              </packing>
+            </child>
             <child>
               <object class="GtkComboBox" id="input_format_combobox">
                 <property name="visible">True</property>
@@ -172,9 +184,24 @@
               </object>
               <packing>
                 <property name="left_attach">2</property>
-                <property name="top_attach">4</property>
+                <property name="top_attach">5</property>
               </packing>
             </child>
+            <child>
+              <object class="GtkButton" id="input_format_help_button">
+                <property name="visible">True</property>
+                <property name="can_focus">True</property>
+                <property name="receives_default">False</property>
+                <property name="image">help</property>
+              </object>
+              <packing>
+                <property name="left_attach">1</property>
+                <property name="top_attach">5</property>
+              </packing>
+            </child>
+            <child>
+              <placeholder/>
+            </child>
             <child>
               <placeholder/>
             </child>

uberwriter/application.py

@@ -188,6 +188,8 @@ class Application(Gtk.Application):
             self.window.toggle_gradient_overlay(settings.get_value(key))
         elif key == "input-format":
             self.window.reload_preview()
+        elif key == "sync-scroll":
+            self.window.reload_preview(reshow=True)
         elif key == "stat-default":
             self.window.update_default_stat()
         elif key == "preview-mode":

uberwriter/main_window.py

@@ -433,8 +433,8 @@ class MainWindow(StyledWindow):
         elif self.overlay_id:
             self.scrolled_window.disconnect(self.overlay_id)
 
-    def reload_preview(self):
-        self.preview_handler.reload()
+    def reload_preview(self, reshow=False):
+        self.preview_handler.reload(reshow=reshow)
 
     def load_file(self, filename=None):
         """Open File from command line or open / open recent etc."""

uberwriter/preferences_dialog.py

@@ -82,6 +82,10 @@ class PreferencesDialog:
         self.gradient_overlay_switch.set_active(self.settings.get_value("gradient-overlay"))
         self.gradient_overlay_switch.connect("state-set", self.on_gradient_overlay)
 
+        self.sync_scroll_switch = self.builder.get_object("sync_scroll_switch")
+        self.sync_scroll_switch.set_active(self.settings.get_value("sync-scroll"))
+        self.sync_scroll_switch.connect("state-set", self.on_sync_scroll)
+
         input_format_store = Gtk.ListStore(int, str)
         input_format = self.settings.get_string("input-format")
         input_format_active = 0
@@ -126,6 +130,10 @@ class PreferencesDialog:
         self.settings.set_value("gradient-overlay", GLib.Variant.new_boolean(state))
         return False
 
+    def on_sync_scroll(self, _, state):
+        self.settings.set_value("sync-scroll", GLib.Variant.new_boolean(state))
+        return False
+
     def on_input_format(self, combobox):
         fmt = self.formats[combobox.get_active()]
         self.settings.set_value("input-format", GLib.Variant.new_string(fmt["format"]))

uberwriter/preview_handler.py

@@ -6,6 +6,7 @@ import gi
 
 from uberwriter.helpers import get_builder
 from uberwriter.preview_renderer import PreviewRenderer
+from uberwriter.settings import Settings
 
 gi.require_version('WebKit2', '4.0')
 from gi.repository import WebKit2, GLib
@@ -43,9 +44,11 @@ class PreviewHandler:
 
         window.connect("style-updated", self.reload)
 
+        self.text_changed_handler_id = None
+
+        self.settings = Settings.new()
         self.web_scroll_handler_id = None
         self.text_scroll_handler_id = None
-        self.text_changed_handler_id = None
 
         self.loading = False
         self.shown = False
@@ -78,7 +81,7 @@ class PreviewHandler:
             if self.web_view.is_loading():
                 self.web_view_pending_html = html
             else:
-                self.web_view.load_html(html, 'file://localhost/')
+                self.web_view.load_html(html, "file://localhost/")
 
         elif step == Step.RENDER:
             # Last step: show the preview. This is a one-time step.
@@ -86,32 +89,41 @@ class PreviewHandler:
                 return
             self.shown = True
 
+            self.text_changed_handler_id = \
+                self.text_view.get_buffer().connect("changed", self.__show)
+
             GLib.idle_add(self.web_view.set_scroll_scale, self.text_view.get_scroll_scale())
 
             self.preview_renderer.show(self.web_view)
 
-            self.text_changed_handler_id = \
-                self.text_view.get_buffer().connect("changed", self.__show)
-            self.web_scroll_handler_id = \
-                self.web_view.connect("scroll-scale-changed", self.on_web_view_scrolled)
-            self.text_scroll_handler_id = \
-                self.text_view.connect("scroll-scale-changed", self.on_text_view_scrolled)
+            if self.settings.get_boolean("sync-scroll"):
+                self.web_scroll_handler_id = \
+                    self.web_view.connect("scroll-scale-changed", self.on_web_view_scrolled)
+                self.text_scroll_handler_id = \
+                    self.text_view.connect("scroll-scale-changed", self.on_text_view_scrolled)
 
-    def reload(self, *_):
+    def reload(self, *_widget, reshow=False):
         if self.shown:
+            if reshow:
+                self.hide()
             self.show()
 
     def hide(self):
         if self.shown:
             self.shown = False
 
+            self.text_view.get_buffer().disconnect(self.text_changed_handler_id)
+
             GLib.idle_add(self.text_view.set_scroll_scale, self.web_view.get_scroll_scale())
 
             self.preview_renderer.hide(self.web_view)
 
-            self.text_view.get_buffer().disconnect(self.text_changed_handler_id)
-            self.text_view.disconnect(self.text_scroll_handler_id)
-            self.web_view.disconnect(self.web_scroll_handler_id)
+            if self.text_scroll_handler_id:
+                self.text_view.disconnect(self.text_scroll_handler_id)
+                self.text_scroll_handler_id = None
+            if self.web_scroll_handler_id:
+                self.web_view.disconnect(self.web_scroll_handler_id)
+                self.web_scroll_handler_id = None
 
         if self.loading:
             self.loading = False

uberwriter/preview_renderer.py

@@ -18,6 +18,8 @@ class PreviewRenderer:
 
     def __init__(
             self, main_window, content, editor, text_view, preview, mode_revealer, mode_button):
+        self.main_window = main_window
+        self.main_window.connect("delete-event", self.on_window_closed)
         self.content = content
         self.editor = editor
         self.text_view = text_view
@@ -25,14 +27,13 @@ class PreviewRenderer:
         self.mode_revealer = mode_revealer
         self.mode_button = mode_button
         self.mode_button.connect("clicked", self.show_mode_popover)
-        self.popover = None
+
         self.settings = Settings.new()
-        self.main_window = main_window
-        self.main_window.connect("delete-event", self.on_window_closed)
+        self.popover = None
         self.window = None
         self.headerbar = None
-        self.mode = self.settings.get_enum("preview-mode")
 
+        self.mode = self.settings.get_enum("preview-mode")
         self.update_mode()
 
     def show(self, web_view):