Add custom actions symbolic icons

Using gresource file and based on the suggestions for the merge menu
made in #90.

Author: oscfdezdz

data/diffuse.gresource.xml

@@ -0,0 +1,11 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<gresources>
+  <gresource prefix="/io/github/mightycreak/Diffuse/icons/scalable/actions">
+    <file preprocess="xml-stripblanks" alias="new-2way-merge-symbolic.svg">icons/hicolor/scalable/actions/new-2way-merge-symbolic.svg</file>
+    <file preprocess="xml-stripblanks" alias="new-3way-merge-symbolic.svg">icons/hicolor/scalable/actions/new-3way-merge-symbolic.svg</file>
+    <file preprocess="xml-stripblanks" alias="copy-selection-left-symbolic.svg">icons/hicolor/scalable/actions/copy-selection-left-symbolic.svg</file>
+    <file preprocess="xml-stripblanks" alias="copy-selection-right-symbolic.svg">icons/hicolor/scalable/actions/copy-selection-right-symbolic.svg</file>
+    <file preprocess="xml-stripblanks" alias="copy-left-into-selection-symbolic.svg">icons/hicolor/scalable/actions/copy-left-into-selection-symbolic.svg</file>
+    <file preprocess="xml-stripblanks" alias="copy-right-into-selection-symbolic.svg">icons/hicolor/scalable/actions/copy-right-into-selection-symbolic.svg</file>
+  </gresource>
+</gresources>

data/icons/hicolor/scalable/actions/copy-left-into-selection-symbolic.svg

@@ -1,4 +1,12 @@
 pkgdatadir = join_paths(get_option('prefix'), get_option('datadir'), meson.project_name())
+gnome = import('gnome')
+
+gnome.compile_resources(meson.project_name(),
+  meson.project_name() + '.gresource.xml',
+  gresource_bundle: true,
+  install: true,
+  install_dir: pkgdatadir,
+)
 
 if build_machine.system() == 'linux'
   desktop_file = i18n.merge_file(

data/icons/hicolor/scalable/actions/copy-right-into-selection-symbolic.svg

@@ -19,9 +19,12 @@
 # with this program; if not, write to the Free Software Foundation, Inc.,
 # 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 
+import os
 import sys
 import gettext
 
+from gi.repository import Gio
+
 VERSION = '@VERSION@'
 PKGDATADIR = '@PKGDATADIR@'
 LOCALEDIR = '@LOCALEDIR@'
@@ -34,4 +37,9 @@ gettext.textdomain('diffuse')
 
 if __name__ == '__main__':
     from diffuse import main
+
+    resource = Gio.resource_load(
+        os.path.join(PKGDATADIR, 'diffuse.gresource'))
+    Gio.Resource._register(resource)
+
     sys.exit(main.main(VERSION, SYSCONFIGDIR))

data/icons/hicolor/scalable/actions/copy-selection-left-symbolic.svg

@@ -914,21 +914,21 @@ def __init__(self, rc_dir, **kwargs):
         # create toolbar
         hbox = Gtk.Box(orientation=Gtk.Orientation.HORIZONTAL, spacing=0)
         button_specs = [
-            [DIFFUSE_STOCK_NEW_2WAY_MERGE, self.new_2_way_file_merge_cb, None, _('New 2-Way File Merge')],  # noqa: E501
-            [DIFFUSE_STOCK_NEW_3WAY_MERGE, self.new_3_way_file_merge_cb, None, _('New 3-Way File Merge')],  # noqa: E501
+            ['new-2way-merge-symbolic', self.new_2_way_file_merge_cb, None, _('New 2-Way File Merge')],  # noqa: E501
+            ['new-3way-merge-symbolic', self.new_3_way_file_merge_cb, None, _('New 3-Way File Merge')],  # noqa: E501
             [],
             ['system-run-symbolic', self.button_cb, 'realign-all', _('Realign All')],
             ['go-top-symbolic', self.button_cb, 'first-difference', _('First Difference')],
             ['go-up-symbolic', self.button_cb, 'previous-difference', _('Previous Difference')],
             ['go-down-symbolic', self.button_cb, 'next-difference', _('Next Difference')],
             ['go-bottom-symbolic', self.button_cb, 'last-difference', _('Last Difference')],
             [],
-            ['go-last-symbolic', self.button_cb, 'copy-selection-right', _('Copy Selection Right')],  # noqa: E501
-            ['go-first-symbolic', self.button_cb, 'copy-selection-left', _('Copy Selection Left')],
-            ['go-next-symbolic', self.button_cb, 'copy-left-into-selection', _('Copy Left Into Selection')],  # noqa: E501
-            ['go-previous-symbolic', self.button_cb, 'copy-right-into-selection', _('Copy Right Into Selection')],  # noqa: E501
-            [DIFFUSE_STOCK_LEFT_RIGHT, self.button_cb, 'merge-from-left-then-right', _('Merge From Left Then Right')],  # noqa: E501
-            [DIFFUSE_STOCK_RIGHT_LEFT, self.button_cb, 'merge-from-right-then-left', _('Merge From Right Then Left')],  # noqa: E501
+            ['copy-selection-right-symbolic', self.button_cb, 'copy-selection-right', _('Copy Selection Right')],  # noqa: E501
+            ['copy-selection-left-symbolic', self.button_cb, 'copy-selection-left', _('Copy Selection Left')],  # noqa: E501
+            ['copy-left-into-selection-symbolic', self.button_cb, 'copy-left-into-selection', _('Copy Left Into Selection')],  # noqa: E501
+            ['copy-right-into-selection-symbolic', self.button_cb, 'copy-right-into-selection', _('Copy Right Into Selection')],  # noqa: E501
+            ['document-revert-rtl-symbolic', self.button_cb, 'merge-from-left-then-right', _('Merge From Left Then Right')],  # noqa: E501
+            ['document-revert-symbolic', self.button_cb, 'merge-from-right-then-left', _('Merge From Right Then Left')],  # noqa: E501
             [],
             ['edit-undo-symbolic', self.button_cb, 'undo', _('Undo')],
             ['edit-redo-symbolic', self.button_cb, 'redo', _('Redo')],
@@ -1811,10 +1811,7 @@ def _append_buttons(box, size, specs):
             button.set_relief(Gtk.ReliefStyle.NONE)
             button.set_can_focus(False)
             image = Gtk.Image()
-            if icon_name.startswith('diffuse'):
-                image.set_from_stock(icon_name, size)
-            else:
-                image.set_from_icon_name(icon_name, size)
+            image.set_from_icon_name(icon_name, size)
             button.add(image)
             image.show()
             button.connect('clicked', cb, cb_data)