Check for icon aliases

The aliases are defined by a file in the (system or user) image
directory. The format is pretty simple: each line is like
  <str1> <str2>
Where every instance of <str1> will be replaced with <str2>.

Fixes bug #12509.

lib/Makefile.am

@@ -8,7 +8,7 @@ EXTRA_DIST = examples/CMakeLists.txt scripts/CMakeLists.txt examples/README.new_
 
 dist_pkgdata_DATA = CREDITS autocorrect chkconfig.ltx \
 	encodings layouttranslations languages latexfonts RELEASE-NOTES \
-	symbols syntax.default unicodesymbols
+	symbols syntax.default unicodesymbols images/icon.aliases
 
 # We use DATA now instead of PYTHON because automake 1.11.2 complains.
 # Note that we "chmod 755" manually this file in install-data-hook.

lib/images/icon.aliases

@@ -0,0 +1,6 @@
+# Aliases for icon names. This allows to avoid duplication of icons
+# Each line is of the form
+#   <original substring> <replacement substring>
+dialog-toggle dialog-show
+layout_ layout-toggle_
+tabular-feature_set tabular-feature_toggle

lib/ui/stdtoolbars.inc

@@ -28,7 +28,7 @@
 #
 # Toolbar "name" "GUI Name"
 #
-# Only seven commands are allowed inside the Toolbar and End
+# Only eight commands are allowed inside the Toolbar and End
 # directives:
 #   Item "The tooltip" "<action> [<parameter>]" adds an icon to the toolbar performing
 #          "<action> <parameter>"
@@ -37,9 +37,9 @@
 #      Item Emphasized set-emph
 #
 #   BidiItem is like Item, but an alternative icon (with name ending
-#   with "+rtl") will be used <hen the paragraph has a right-to-left
-#   layout. If this alternative icon does not exist, the LtR icon will
-#   be mirrored instead.
+#     with "+rtl") will be used <hen the paragraph has a right-to-left
+#     layout. If this alternative icon does not exist, the LtR icon will
+#     be mirrored instead.
 #
 #   Layouts adds the layouts combo-box to the toolbar
 #
@@ -48,23 +48,26 @@
 #   Minibuffer adds the command buffer (only one may exist)
 #
 #   TableInsert "The tooltip" adds a special widget for quick
-#   insertion of tables
+#     insertion of tables
 #
 #   PopupMenu "name" "The tooltip"
 #
-#   ... inserts a button with a popup menu derived from Toolbar "name"
+#     ... inserts a button with a popup menu derived from Toolbar "name"
 #
 #   IconPalette "name" "The tooltip"
 #
-#   ... inserts a button with a popup iconpalette derived from Toolbar "name"
+#     ... inserts a button with a popup icon palette derived from Toolbar "name"
 #
 #
-# The icons are found in the lib/images/ direcory under the name
+# The icons are found in the lib/images/ directory under the name
 # action.png or action_parameter.png, except for math-insert, which
 # is e.g. lib/image/math/sum.png. Note that some characters are
 # replaced (e.g. ')' -> rbracket).
 #
-#  All other lyx commands will get a "unknown" icon.
+# Note that the lib/images/icon.aliases file can be used to specify
+# fallback icons for some functions.
+#
+#  All other LyX commands will get a "unknown" icon.
 #
 # This is the default toolbar:
 

src/frontends/qt/GuiApplication.cpp

@@ -525,6 +525,36 @@ QString themeIconName(QString const & action)
 }
 
 
+namespace {
+
+QString getAlias(QString name) {
+	static bool has_aliases = false;
+	static vector <pair<QString,QString>> aliases;
+	// Initialize aliases list (once).
+	if (!has_aliases) {
+		FileName alfile = libFileSearch("images", "icon.aliases");
+		if (alfile.exists()) {
+			Lexer lex;
+			lex.setFile(alfile);
+			while(lex.isOK()) {
+				string from, to;
+				lex >> from >> to;
+				if (!from.empty())
+					aliases.push_back({toqstr(from), toqstr(to)});
+			}
+		}
+		has_aliases = true;
+	}
+	// check for the following aliases
+	for (auto alias : aliases) {
+		if (name.contains(alias.first))
+			name.replace(alias.first, alias.second);
+	}
+	return name;
+}
+
+}
+
 IconInfo iconInfo(FuncRequest const & f, bool unknown, bool rtl)
 {
 	IconInfo res;
@@ -538,9 +568,10 @@ IconInfo iconInfo(FuncRequest const & f, bool unknown, bool rtl)
 		name.replace(' ', '_');
 		name.replace(';', '_');
 		name.replace('\\', "backslash");
-		// avoid duplication for these
-		name.replace("dialog-toggle", "dialog-show");
 		names << name;
+		QString alias = getAlias(name);
+		if (alias != name)
+			names << alias;
 
 		// then special default icon for some lfuns
 		switch (f.action()) {
@@ -572,6 +603,9 @@ IconInfo iconInfo(FuncRequest const & f, bool unknown, bool rtl)
 
 	// next thing to try is function name alone
 	names << lfunname;
+	QString alias = getAlias(lfunname);
+	if (alias != lfunname)
+		names << alias;
 
 	// and finally maybe the unknown icon
 	if (unknown)