Extract ScrolledWindow in the widgets module

Author: MightyCreak

src/main.py

@@ -46,6 +46,7 @@
 from diffuse.preferences import Preferences
 from diffuse.resources import Resources
 from diffuse.vcs.vcs_registry import VcsRegistry
+from diffuse.widgets import ScrolledWindow
 
 # avoid some dictionary lookups when string.whitespace is used in loops
 # this is sorted based upon frequency to speed up code for stripping whitespace
@@ -178,111 +179,6 @@ def convert_to_format(s, format):
                 s += '\r'
     return s
 
-# utility method to step advance an adjustment
-def step_adjustment(adj, delta):
-    v = adj.get_value() + delta
-    # clamp to the allowed range
-    v = max(v, int(adj.get_lower()))
-    v = min(v, int(adj.get_upper() - adj.get_page_size()))
-    adj.set_value(v)
-
-# This is a replacement for Gtk.ScrolledWindow as it forced expose events to be
-# handled immediately after changing the viewport position.  This could cause
-# the application to become unresponsive for a while as it processed a large
-# queue of keypress and expose event pairs.
-class ScrolledWindow(Gtk.Grid):
-    scroll_directions = set((Gdk.ScrollDirection.UP,
-                             Gdk.ScrollDirection.DOWN,
-                             Gdk.ScrollDirection.LEFT,
-                             Gdk.ScrollDirection.RIGHT))
-
-    def __init__(self, hadj, vadj):
-        Gtk.Grid.__init__(self)
-        self.position = (0, 0)
-        self.scroll_count = 0
-        self.partial_redraw = False
-
-        self.hadj, self.vadj = hadj, vadj
-        vport = Gtk.Viewport.new()
-        darea = Gtk.DrawingArea.new()
-        darea.add_events(Gdk.EventMask.SCROLL_MASK)
-        self.darea = darea
-        # replace darea's queue_draw_area with our own so we can tell when
-        # to disable/enable our scrolling optimisation
-        self.darea_queue_draw_area = darea.queue_draw_area
-        darea.queue_draw_area = self.redraw_region
-        vport.add(darea)
-        darea.show()
-        self.attach(vport, 0, 0, 1, 1)
-        vport.set_vexpand(True)
-        vport.set_hexpand(True)
-        vport.show()
-
-        self.vbar = bar = Gtk.Scrollbar.new(Gtk.Orientation.VERTICAL, vadj)
-        self.attach(bar, 1, 0, 1, 1)
-        bar.show()
-
-        self.hbar = bar = Gtk.Scrollbar.new(Gtk.Orientation.HORIZONTAL, hadj)
-        self.attach(bar, 0, 1, 1, 1)
-        bar.show()
-
-        # listen to our signals
-        hadj.connect('value-changed', self.value_changed_cb)
-        vadj.connect('value-changed', self.value_changed_cb)
-        darea.connect('configure-event', self.configure_cb)
-        darea.connect('scroll-event', self.scroll_cb)
-        darea.connect('draw', self.draw_cb)
-
-    # updates the adjustments to match the new widget size
-    def configure_cb(self, widget, event):
-        w, h = event.width, event.height
-        for adj, d in (self.hadj, w), (self.vadj, h):
-            v = adj.get_value()
-            if v + d > adj.get_upper():
-                adj.set_value(max(0, adj.get_upper() - d))
-            adj.set_page_size(d)
-            adj.set_page_increment(d)
-
-    # update the vertical adjustment when the mouse's scroll wheel is used
-    def scroll_cb(self, widget, event):
-        d = event.direction
-        if d in self.scroll_directions:
-            delta = 100
-            if d in (Gdk.ScrollDirection.UP, Gdk.ScrollDirection.LEFT):
-                delta = -delta
-            vertical = (d in (Gdk.ScrollDirection.UP, Gdk.ScrollDirection.DOWN))
-            if event.state & Gdk.ModifierType.SHIFT_MASK:
-                vertical = not vertical
-            if vertical:
-                adj = self.vadj
-            else:
-                adj = self.hadj
-            step_adjustment(adj, delta)
-
-    def value_changed_cb(self, widget):
-        old_x, old_y = self.position
-        pos_x = int(self.hadj.get_value())
-        pos_y = int(self.vadj.get_value())
-        self.position = (pos_x, pos_y)
-        if self.darea.get_window() is not None:
-            # window.scroll() although visually nice, is slow, revert to
-            # queue_draw() if scroll a lot without seeing an expose event
-            if self.scroll_count < 2 and not self.partial_redraw:
-                self.scroll_count += 1
-                self.darea.get_window().scroll(old_x - pos_x, old_y - pos_y)
-            else:
-                self.partial_redraw = False
-                self.darea.queue_draw()
-
-    def draw_cb(self, widget, cr):
-        self.scroll_count = 0
-
-    # replacement for darea.queue_draw_area that notifies us when a partial
-    # redraw happened
-    def redraw_region(self, x, y, w, h):
-        self.partial_redraw = True
-        self.darea_queue_draw_area(x, y, w, h)
-
 # Enforcing manual alignment is accomplished by dividing the lines of text into
 # sections that are matched independently.  'blocks' is an array of integers
 # describing how many lines (including null lines for spacing) that are in each
@@ -2770,9 +2666,9 @@ def diffmap_button_press_cb(self, widget, event):
     def diffmap_scroll_cb(self, widget, event):
         delta = 100
         if event.direction == Gdk.ScrollDirection.UP:
-            step_adjustment(self.vadj, -delta)
+            utils.step_adjustment(self.vadj, -delta)
         elif event.direction == Gdk.ScrollDirection.DOWN:
-            step_adjustment(self.vadj, delta)
+            utils.step_adjustment(self.vadj, delta)
 
     # redraws the overview map when a portion is exposed
     def diffmap_draw_cb(self, widget, cr):

src/meson.build

@@ -37,6 +37,7 @@ diffuse_sources = [
   'preferences.py',
   'resources.py',
   'utils.py',
+  'widgets.py',
 ]
 
 install_data(diffuse_sources, install_dir: moduledir)

src/utils.py

@@ -264,6 +264,14 @@ def null_to_empty(s):
         s = ''
     return s
 
+# utility method to step advance an adjustment
+def step_adjustment(adj, delta):
+    v = adj.get_value() + delta
+    # clamp to the allowed range
+    v = max(v, int(adj.get_lower()))
+    v = min(v, int(adj.get_upper() - adj.get_page_size()))
+    adj.set_value(v)
+
 
 # use the program's location as a starting place to search for supporting files
 # such as icon and help documentation
@@ -279,9 +287,9 @@ def null_to_empty(s):
 if isWindows():
     # gettext looks for the language using environment variables which
     # are normally not set on Windows so we try setting it for them
-    for v in 'LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE':
-        if v in os.environ:
-            lang = os.environ[v]
+    for lang_env in 'LC_ALL', 'LC_CTYPE', 'LANG', 'LANGUAGE':
+        if lang_env in os.environ:
+            lang = os.environ[lang_env]
             # remove any additional languages, encodings, or modifications
             for c in ':.@':
                 lang = lang.split(c)[0]

src/widgets.py

@@ -0,0 +1,124 @@
+# Diffuse: a graphical tool for merging and comparing text files.
+#
+# Copyright (C) 2019 Derrick Moser <[email protected]>
+# Copyright (C) 2021 Romain Failliot <[email protected]>
+#
+# This program is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 2 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 General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License along
+# with this program; if not, write to the Free Software Foundation, Inc.,
+# 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
+
+# pylint: disable=wrong-import-position
+import gi
+gi.require_version('Gtk', '3.0')
+gi.require_version('Gdk', '3.0')
+from gi.repository import Gtk, Gdk
+# pylint: enable=wrong-import-position
+
+from diffuse import utils
+
+# This is a replacement for Gtk.ScrolledWindow as it forced expose events to be
+# handled immediately after changing the viewport position.  This could cause
+# the application to become unresponsive for a while as it processed a large
+# queue of keypress and expose event pairs.
+class ScrolledWindow(Gtk.Grid):
+    scroll_directions = set((Gdk.ScrollDirection.UP,
+                             Gdk.ScrollDirection.DOWN,
+                             Gdk.ScrollDirection.LEFT,
+                             Gdk.ScrollDirection.RIGHT))
+
+    def __init__(self, hadj, vadj):
+        Gtk.Grid.__init__(self)
+        self.position = (0, 0)
+        self.scroll_count = 0
+        self.partial_redraw = False
+
+        self.hadj, self.vadj = hadj, vadj
+        vport = Gtk.Viewport.new()
+        darea = Gtk.DrawingArea.new()
+        darea.add_events(Gdk.EventMask.SCROLL_MASK)
+        self.darea = darea
+        # replace darea's queue_draw_area with our own so we can tell when
+        # to disable/enable our scrolling optimisation
+        self.darea_queue_draw_area = darea.queue_draw_area
+        darea.queue_draw_area = self.redraw_region
+        vport.add(darea)
+        darea.show()
+        self.attach(vport, 0, 0, 1, 1)
+        vport.set_vexpand(True)
+        vport.set_hexpand(True)
+        vport.show()
+
+        self.vbar = Gtk.Scrollbar.new(Gtk.Orientation.VERTICAL, vadj)
+        self.attach(self.vbar, 1, 0, 1, 1)
+        self.vbar.show()
+
+        self.hbar = Gtk.Scrollbar.new(Gtk.Orientation.HORIZONTAL, hadj)
+        self.attach(self.hbar, 0, 1, 1, 1)
+        self.hbar.show()
+
+        # listen to our signals
+        hadj.connect('value-changed', self.value_changed_cb)
+        vadj.connect('value-changed', self.value_changed_cb)
+        darea.connect('configure-event', self.configure_cb)
+        darea.connect('scroll-event', self.scroll_cb)
+        darea.connect('draw', self.draw_cb)
+
+    # updates the adjustments to match the new widget size
+    def configure_cb(self, widget, event):
+        w, h = event.width, event.height
+        for adj, d in (self.hadj, w), (self.vadj, h):
+            v = adj.get_value()
+            if v + d > adj.get_upper():
+                adj.set_value(max(0, adj.get_upper() - d))
+            adj.set_page_size(d)
+            adj.set_page_increment(d)
+
+    # update the vertical adjustment when the mouse's scroll wheel is used
+    def scroll_cb(self, widget, event):
+        d = event.direction
+        if d in self.scroll_directions:
+            delta = 100
+            if d in (Gdk.ScrollDirection.UP, Gdk.ScrollDirection.LEFT):
+                delta = -delta
+            vertical = (d in (Gdk.ScrollDirection.UP, Gdk.ScrollDirection.DOWN))
+            if event.state & Gdk.ModifierType.SHIFT_MASK:
+                vertical = not vertical
+            if vertical:
+                adj = self.vadj
+            else:
+                adj = self.hadj
+            utils.step_adjustment(adj, delta)
+
+    def value_changed_cb(self, widget):
+        old_x, old_y = self.position
+        pos_x = int(self.hadj.get_value())
+        pos_y = int(self.vadj.get_value())
+        self.position = (pos_x, pos_y)
+        if self.darea.get_window() is not None:
+            # window.scroll() although visually nice, is slow, revert to
+            # queue_draw() if scroll a lot without seeing an expose event
+            if self.scroll_count < 2 and not self.partial_redraw:
+                self.scroll_count += 1
+                self.darea.get_window().scroll(old_x - pos_x, old_y - pos_y)
+            else:
+                self.partial_redraw = False
+                self.darea.queue_draw()
+
+    def draw_cb(self, widget, cr):
+        self.scroll_count = 0
+
+    # replacement for darea.queue_draw_area that notifies us when a partial
+    # redraw happened
+    def redraw_region(self, x, y, w, h):
+        self.partial_redraw = True
+        self.darea_queue_draw_area(x, y, w, h)