Add support for translation of strings found in darktable styles.

Remove the hack added in view/darkroom.c for two strings now
auto-generated.

po/POTFILES.in

@@ -1,5 +1,6 @@
 build/bin/conf_gen.h
 build/bin/preferences_gen.h
+build/bin/styles_string.h
 build/bin/tools/darktable_authors.h
 build/lib/darktable/plugins/introspection_ashift.c
 build/lib/darktable/plugins/introspection_atrous.c

src/CMakeLists.txt

@@ -919,6 +919,19 @@ else(NOT ${Xsltproc_BIN} STREQUAL "Xsltproc_BIN-NOTFOUND")
   endif(NOT ${Saxon_BIN} STREQUAL "Saxon_BIN-NOTFOUND")
 endif(NOT ${Xsltproc_BIN} STREQUAL "Xsltproc_BIN-NOTFOUND")
 
+add_custom_command(
+  DEPENDS ${DARKTABLE_DATADIR}/styles/*.dtstyle
+  OUTPUT ${CMAKE_CURRENT_BINARY_DIR}/styles_string.h
+  COMMAND ${CMAKE_SOURCE_DIR}/tools/generate_styles_string.sh ${DARKTABLE_DATADIR}/styles ${CMAKE_CURRENT_BINARY_DIR}/styles_string.h
+  COMMENT "Generating styles strings for translation"
+)
+
+add_custom_target(
+  generate_styles_string ALL
+  DEPENDS ${CMAKE_CURRENT_BINARY_DIR}/styles_string.h
+  WORKING_DIRECTORY ${CMAKE_SOURCE_DIR}
+)
+
 add_custom_target(
   generate_preferences ALL
   DEPENDS ${CMAKE_SOURCE_DIR}/tools/generate_prefs.xsl ${CMAKE_SOURCE_DIR}/data/darktableconfig.dtd ${DARKTABLE_DATADIR}/darktableconfig.xml ${CMAKE_CURRENT_BINARY_DIR}/preferences_gen.h
@@ -942,6 +955,7 @@ add_library(lib_darktable SHARED ${DARKTABLE_BINDIR}/preferences_gen.h ${DARKTAB
 # since this isn't the same directory we do have to manually set it
 set_source_files_properties(${DARKTABLE_BINDIR}/version_gen.c PROPERTIES GENERATED TRUE)
 
+add_dependencies(lib_darktable generate_styles_string)
 add_dependencies(lib_darktable generate_conf)
 add_dependencies(lib_darktable generate_version)
 add_dependencies(lib_darktable generate_preferences)

src/views/darkroom.c

@@ -2366,8 +2366,6 @@ void gui_init(dt_view_t *self)
   dt_gui_add_help_link(styles, "bottom_panel_styles");
   dt_view_manager_view_toolbox_add(darktable.view_manager, styles, DT_VIEW_DARKROOM);
   /* ensure that we get strings from the style files shipped with darktable localized */
-  (void)_("darktable camera styles");
-  (void)_("generic");
 
   /* create second window display button */
   dev->second_wnd_button = dtgtk_togglebutton_new(dtgtk_cairo_paint_display2, 0, NULL);

tools/generate_styles_string.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+
+STYLE_DIR=$1
+OUT=$2
+
+# Get the l10n strings from styles. Such strings are prefixed by _l10n_
+function get-l10n()
+{
+    #  1. Get the "name" node value using xsltproc
+    #
+    #  2. Cut substrings separated with | and keep only those
+    #     with _l10n_ prefix.
+    #
+    #  3. Remove all _l10n_ sentinel with sed
+    #
+    #  4. Finaly generates into the while loop the pseudo C code for
+    #     the strings to be translated.
+
+    xsltproc <( echo '<?xml version="1.0"?>
+                      <xsl:stylesheet version="1.0"
+                               xmlns:xsl="http://www.w3.org/1999/XSL/Transform">
+                        <xsl:output indent="yes" omit-xml-declaration="yes"/>
+                        <xsl:template match="info">
+                          <xsl:value-of select="name"/>
+                        </xsl:template>
+
+                        <xsl:template match="style"/>
+
+                      </xsl:stylesheet>' ) $1 |
+        tr '|' '\n' | grep _l10n_ | sed 's/_l10n_//g' |
+        while read line; do
+            echo "_(\"$line\")"
+        done
+}
+
+export IFS=$'\n'
+
+{
+    echo "// Not to be compiled, generated for translation only"
+    echo
+
+    #  Ensure that we remove the duplicate strings
+
+    ls $STYLE_DIR/*.dtstyle | while read file; do
+        get-l10n $file
+    done | sort | uniq
+} > $OUT