[gimp] tools: scripts to extract a single SVG icon from a source file.

[Jehan Pagès <jehanp src gnome org>]

commit b0af146ea3f387ef1981283a329eea4a9b8a4103
Author: Jehan <jehan girinstud io>
Date:   Sun Feb 14 00:27:46 2016 +0100

    tools: scripts to extract a single SVG icon from a source file.
    
    SVG sources contains many icons and each icon is extracted by its id.

 tools/Makefile.am            |   14 ++++-
 tools/compute-svg-viewbox.c  |   85 ++++++++++++++++++++++++++++++
 tools/extract-vector-icon.sh |  117 ++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 214 insertions(+), 2 deletions(-)
---
diff --git a/tools/Makefile.am b/tools/Makefile.am
index a6c8617..4de2be2 100644
--- a/tools/Makefile.am
+++ b/tools/Makefile.am
@@ -3,7 +3,9 @@
 libgimpbase = $(top_builddir)/libgimpbase/libgimpbase-$(GIMP_API_VERSION).la
 
 if ENABLE_VECTOR_ICONS
-invert_svg = invert-svg
+svg_icon_tools = invert-svg compute-svg-viewbox
+else
+svg_icon_tools =
 endif
 
 if WITH_PDBGEN
@@ -28,7 +30,7 @@ bin_PROGRAMS = gimptool-2.0
 
 endif
 
-noinst_PROGRAMS = test-clipboard $(invert_svg)
+noinst_PROGRAMS = test-clipboard $(svg_icon_tools)
 
 EXTRA_PROGRAMS = \
        kernelgen
@@ -53,6 +55,14 @@ invert_svg_SOURCES = invert-svg.c
 invert_svg_LDADD = \
        $(GLIB_LIBS)    \
        $(GIO_LIBS)
+
+compute_svg_viewbox_SOURCES = compute-svg-viewbox.c
+
+compute_svg_viewbox_CFLAGS = \
+       $(SVG_CFLAGS)
+
+compute_svg_viewbox_LDADD = \
+       $(SVG_LIBS)
 endif
 
 AM_CPPFLAGS = \
diff --git a/tools/compute-svg-viewbox.c b/tools/compute-svg-viewbox.c
new file mode 100644
index 0000000..4fbf195
--- /dev/null
+++ b/tools/compute-svg-viewbox.c
@@ -0,0 +1,85 @@
+/* compute-svg-viewbox.c
+ * Copyright (C) 2016 Jehan
+ *
+ * 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 3 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, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <librsvg/rsvg.h>
+#include <stdio.h>
+#include <stdlib.h>
+
+int main (int argc, char **argv)
+{
+  RsvgHandle        *handle;
+  RsvgPositionData   position_data;
+  RsvgDimensionData  dimension;
+
+  gchar             *endptr;
+  gchar             *path;
+  gchar             *id;
+  gint               prev_x;
+  gint               prev_y;
+
+  if (argc != 5)
+    {
+      fprintf (stderr, "Usage: compute-svg-viewbox path object_id x y\n");
+      return 1;
+    }
+  prev_x = strtol (argv[3], &endptr, 10);
+  if (endptr == argv[3])
+    {
+      fprintf (stderr, "Error: the third parameter must be an integer\n");
+      return 1;
+    }
+  prev_y = strtol (argv[4], &endptr, 10);
+  if (endptr == argv[4])
+    {
+      fprintf (stderr, "Error: the fourth parameter must be an integer\n");
+      return 1;
+    }
+
+  path   = argv[1];
+  handle = rsvg_handle_new_from_file (path, NULL);
+  if (! handle)
+    {
+      fprintf (stderr, "Error: wrong path \"%s\".\n", path);
+      return 1;
+    }
+
+  id = g_strdup_printf("#%s", argv[2]);
+  if (! rsvg_handle_has_sub (handle, id))
+    {
+      fprintf (stderr, "Error: the id \"%s\" does not exist.\n", id);
+      g_object_unref (handle);
+      g_free (id);
+      return 1;
+    }
+
+  rsvg_handle_get_position_sub (handle, &position_data, id);
+  rsvg_handle_get_dimensions_sub (handle, &dimension, id);
+  if (dimension.width != dimension.height)
+    {
+      /* Right now, we are constraining all objects into square objects. */
+      fprintf (stderr, "WARNING: object \"%s\" has unexpected size %dx%d [pos: (%d, %d)].\n",
+               id, dimension.width, dimension.height,
+               position_data.x, position_data.y);
+    }
+  printf("viewBox=\"%d %d %d %d\"",
+         position_data.x + prev_x, position_data.y + prev_y,
+         dimension.width, dimension.height);
+
+  g_object_unref (handle);
+  g_free (id);
+  return 0;
+}
diff --git a/tools/extract-vector-icon.sh b/tools/extract-vector-icon.sh
new file mode 100755
index 0000000..94a6ce7
--- /dev/null
+++ b/tools/extract-vector-icon.sh
@@ -0,0 +1,117 @@
+#!/bin/sh
+# extract-vector-icon.sh
+# Copyright (C) 2016 Jehan
+#
+# 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 3 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, see <http://www.gnu.org/licenses/>.
+
+# This script generates a new SVG file by extracting a single object by
+# its id, from a source SVG, and updating the viewBox (canvas) size and
+# position.
+usage ()
+{
+  printf "Usage: extract-vector-icon.sh source icon-name [width height]\n"
+  printf "Create the file 'icon-name.svg' from the \`source\` SVG.\n"
+}
+
+if [ "$#" != 2 ]; then
+  if [ "$#" != 4 ]; then
+    usage
+    exit 1
+  fi
+fi
+
+# The script is run from $(top_builddir)/icons/Symbolic/
+compute_viewbox="$(pwd)/../../tools/compute-svg-viewbox"
+source="$1"
+id="$2"
+if [ "$#" == 4 ]; then
+  # The expected display width/height for the image.
+  width="$3"
+  height="$4"
+else
+  # We base the design of our scalable icons on 16x16 pixels.
+  width="16"
+  height="16"
+fi
+
+# Extract the icon code.
+#icon=`xmllint "$source" --xpath '//*[local-name()="g" and @id="'$id'"]'`
+icon=`xmllint "$source" --xpath '//*[ id="'$id'"]'`
+# Get rid of any transform on the top node to help librsvg.
+#icon=`echo $icon | sed 's/^\(<[^>]*\) transform="[^"]*"/\1/'`
+if [ $? -ne 0 ]; then
+  >&2 echo "extract-vector-icon.sh: object id \"$id\" not found in \"$source\" ";
+  exit 1;
+fi;
+
+# The typical namespaces declared at start of a SVG made with Inkscape.
+# Since we are not sure of what namespace will use the object XML, and
+# since we don't want to end up with invalid XML, we just keep them all
+# declared here.
+svg_start='<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<!-- Created by GIMP build. -->
+
+<svg
+  xmlns:osb="http://www.openswatchbook.org/uri/2009/osb";
+  xmlns:dc="http://purl.org/dc/elements/1.1/";
+  xmlns:cc="http://creativecommons.org/ns#";
+  xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#";
+  xmlns:svg="http://www.w3.org/2000/svg";
+  xmlns="http://www.w3.org/2000/svg";
+  xmlns:xlink="http://www.w3.org/1999/xlink";
+  xmlns:sodipodi="http://sodipodi.sourceforge.net/DTD/sodipodi-0.dtd";
+  xmlns:inkscape="http://www.inkscape.org/namespaces/inkscape";
+  version="1.1"
+'
+
+# Grab the defined color palette.
+defs=`xmllint "$source" --xpath '//*[local-name()="defs"]'`
+
+# Create a temporary SVG file with the main information.
+svg_temp="`mktemp ./${id}-XXXX.svg`"
+echo "$svg_start>$defs$icon</svg>" > $svg_temp
+
+x=0
+y=0
+# In case the source SVG has a viewBox not starting at (0, 0), get
+# the current origin coordinates.
+#viewBox=`xmllint $svg_temp --xpath '/*[local-name()="svg"]/@viewBox'`
+#if [ $? -eq 0 ]; then
+#  x=`echo $viewBox| sed 's/ *viewBox *= *"\([0-9]\+\) .*$/\1/'`
+#  y=`echo $viewBox| sed 's/ *viewBox *= *"[0-9]\+ \+\([0-9]\+\).*$/\1/'`
+#fi;
+
+# Compute the viewBox that we want to set to our generated SVG.
+viewBox=`$compute_viewbox "$svg_temp" "$id" $x $y`
+if [ $? -ne 0 ]; then
+  >&2 echo "extract-vector-icon.sh: error running \`$compute_viewbox "$tmp" "$id" $x $y\`.";
+  rm -f $svg_temp
+  exit 1;
+fi;
+rm -f $svg_temp
+
+# The finale SVG file with properly set viewBox.
+svg="$svg_start  $viewBox"
+if [ "$#" == 5 ]; then
+  svg="$svg
+  width=\"$width\"
+  height=\"$height\""
+fi
+svg="$svg>
+<title>$id</title>
+$defs
+$icon
+</svg>"
+
+echo "$svg"