[gimp] plug-ins: port gradients-save-as-css to Python 3 + new API.

[Jehan <jehanp src gnome org>]

commit 7777c5fa0cf0f2cc0adb1a08eec8b0e881bb2af5
Author: Jehan <jehan girinstud io>
Date:   Sun Sep 15 10:17:29 2019 +0200

    plug-ins: port gradients-save-as-css to Python 3 + new API.

 plug-ins/pygimp/plug-ins/gradients-save-as-css.py | 104 -------------
 plug-ins/python/Makefile.am                       |   5 +-
 plug-ins/python/gradients-save-as-css.py          | 178 ++++++++++++++++++++++
 plug-ins/python/meson.build                       |   2 +-
 4 files changed, 183 insertions(+), 106 deletions(-)
---
diff --git a/plug-ins/python/Makefile.am b/plug-ins/python/Makefile.am
index e8f6d3f49a..6cf20bb1e5 100644
--- a/plug-ins/python/Makefile.am
+++ b/plug-ins/python/Makefile.am
@@ -9,6 +9,9 @@ file_openraster_SCRIPTS = file-openraster.py
 foggifydir = $(gimpplugindir)/plug-ins/foggify
 foggify_SCRIPTS = foggify.py
 
+gradients_save_as_cssdir = $(gimpplugindir)/plug-ins/gradients-save-as-css
+gradients_save_as_css_SCRIPTS = gradients-save-as-css.py
+
 palette_offsetdir = $(gimpplugindir)/plug-ins/palette-offset
 palette_offset_SCRIPTS = palette-offset.py
 
@@ -23,7 +26,6 @@ spyro_plus_SCRIPTS = spyro-plus.py
 
 # TODO: to be ported:
 ##     colorxhtml.py
-##     gradients-save-as-css.py
 ##     histogram-export.py
 ##     palette-sort.py
 ##     python-eval.py
@@ -39,6 +41,7 @@ endif
 EXTRA_DIST = \
        file-openraster.py              \
        foggify.py                      \
+       gradients-save-as-css.py        \
        palette-offset.py               \
        palette-to-gradient.py          \
        py-slice.py                     \
diff --git a/plug-ins/python/gradients-save-as-css.py b/plug-ins/python/gradients-save-as-css.py
new file mode 100755
index 0000000000..41cb746871
--- /dev/null
+++ b/plug-ins/python/gradients-save-as-css.py
@@ -0,0 +1,178 @@
+#!/usr/bin/env python3
+# -*- coding: utf-8 -*-
+
+#   Allows saving (TODO: and loading) CSS gradient files
+#   Copyright (C) 2011 João S. O. Bueno <gwidion gmail com>
+#
+#   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 <https://www.gnu.org/licenses/>.
+
+
+# Currently this exports all color segments as RGB linear centered segments.
+# TODO: Respect gradient alpha, off-center segments, different blending
+# functions and HSV colors
+
+import gi
+gi.require_version('Gimp', '3.0')
+from gi.repository import Gimp
+from gi.repository import GObject
+from gi.repository import GLib
+from gi.repository import Gio
+import time
+import sys
+
+import gettext
+_ = gettext.gettext
+def N_(message): return message
+
+w3c_template = """background-image: linear-gradient(top, %s);\n"""
+moz_template = """background-image: -moz-linear-gradient(center top, %s);\n"""
+webkit_template = """background-image: -webkit-gradient(linear, """ \
+                  """left top, left bottom, %s);\n"""
+
+color_to_html = lambda c: "rgb(%d,%d,%d)" % (c.r, c.g, c.b)
+
+def format_text(text):
+    counter = 0
+    new_text = []
+    for token in text.split(","):
+        if counter + len(token) > 77:
+            token = "\n    " + token
+            counter = 4
+        new_text.append(token)
+        if "\n" in token:
+            counter = len(token.rsplit("\n")[-1]) + 1
+        else:
+            counter += len(token) + 1
+
+    return ",".join(new_text)
+
+def gradient_css_save(procedure, args, data):
+    if args.length() != 3:
+        error = 'Wrong parameters given'
+        return procedure.new_return_values(Gimp.PDBStatusType.CALLING_ERROR,
+                                           GLib.Error(error))
+    runmode = args.index(0)
+    gradient = args.index(1)
+    file = args.index(2)
+
+    if runmode == Gimp.RunMode.INTERACTIVE:
+        # Interactive mode works on active gradient.
+        gradient = Gimp.context_get_gradient()
+
+        # Pop-up a file chooser for target file.
+        gi.require_version('Gtk', '3.0')
+        from gi.repository import Gtk
+
+        Gimp.ui_init ("gradients-save-as-css.py", False)
+
+        use_header_bar = Gtk.Settings.get_default().get_property("gtk-dialogs-use-header")
+        dialog = Gtk.FileChooserDialog(use_header_bar=use_header_bar,
+                                       title=_("CSS file..."),
+                                       action=Gtk.FileChooserAction.SAVE)
+        dialog.add_button("_Cancel", Gtk.ResponseType.CANCEL)
+        dialog.add_button("_OK", Gtk.ResponseType.OK)
+        dialog.show()
+        if dialog.run() == Gtk.ResponseType.OK:
+            file = dialog.get_file()
+        else:
+            return procedure.new_return_values(Gimp.PDBStatusType.CANCEL,
+                                               GLib.Error())
+
+    if file is None:
+        error = 'No file given'
+        return procedure.new_return_values(Gimp.PDBStatusType.CALLING_ERROR,
+                                           GLib.Error(error))
+
+    stops = []
+    wk_stops = []
+    n_segments = Gimp.gradient_get_number_of_segments(gradient)
+    last_stop = None
+    for index in range(n_segments):
+        success, lcolor, lopacity = Gimp.gradient_segment_get_left_color(gradient, index)
+        success, rcolor, ropacity = Gimp.gradient_segment_get_right_color(gradient, index)
+        success, lpos = Gimp.gradient_segment_get_left_pos(gradient, index)
+        success, rpos = Gimp.gradient_segment_get_right_pos(gradient, index)
+
+        lstop = color_to_html(lcolor) + " %d%%" % int(100 * lpos)
+        wk_lstop = "color-stop(%.03f, %s)" %(lpos, color_to_html(lcolor))
+        if lstop != last_stop:
+            stops.append(lstop)
+            wk_stops.append(wk_lstop)
+
+        rstop = color_to_html(rcolor) + " %d%%" % int(100 * rpos)
+        wk_rstop = "color-stop(%.03f, %s)" %(rpos, color_to_html(rcolor))
+
+        stops.append(rstop)
+        wk_stops.append(wk_rstop)
+        last_stop = rstop
+
+    final_text = w3c_template % ", ".join(stops)
+    final_text += moz_template % ",".join(stops)
+    final_text += webkit_template % ",".join(wk_stops)
+
+    success, etag = file.replace_contents(bytes(format_text(final_text), encoding='utf-8'),
+                                          etag=None,
+                                          make_backup=False,
+                                          flags=Gio.FileCreateFlags.REPLACE_DESTINATION,
+                                          cancellable=None)
+    if success:
+        return procedure.new_return_values(Gimp.PDBStatusType.SUCCESS, GLib.Error())
+    else:
+        return procedure.new_return_values(Gimp.PDBStatusType.EXECUTION_ERROR,
+                                           GLib.Error('File saving failed: {}'.format(file.get_path())))
+
+class GradientsSaveAsCSS (Gimp.PlugIn):
+   ## Parameters ##
+    __gproperties__ = {
+        "run-mode": (Gimp.RunMode,
+                     "Run mode",
+                     "The run mode",
+                     Gimp.RunMode.NONINTERACTIVE,
+                     GObject.ParamFlags.READWRITE),
+        "gradient": (str,
+                     _("Gradient to use"), "", "",
+                     GObject.ParamFlags.READWRITE),
+        "file": (Gio.File,
+                 _("File"), None,
+                 GObject.ParamFlags.READWRITE),
+    }
+
+    ## GimpPlugIn virtual methods ##
+    def do_query_procedures(self):
+        self.set_translation_domain("gimp30-python",
+                                    Gio.file_new_for_path(Gimp.locale_directory()))
+        return [ 'gradient-save-as-css' ]
+
+    def do_create_procedure(self, name):
+        procedure = None
+        if name == 'gradient-save-as-css':
+            procedure = Gimp.Procedure.new(self, name,
+                                           Gimp.PDBProcType.PLUGIN,
+                                           gradient_css_save, None)
+            procedure.set_image_types("*")
+            procedure.set_documentation ("Creates a new palette from a given gradient",
+                                         "palette_from_gradient (gradient, number, segment_colors) -> None",
+                                         name)
+            procedure.set_menu_label("Save as CSS...")
+            procedure.set_attribution("Joao S. O. Bueno",
+                                      "(c) GPL V3.0 or later",
+                                      "2011")
+            procedure.add_menu_path('<Gradients>')
+
+            procedure.add_argument_from_property(self, "run-mode")
+            procedure.add_argument_from_property(self, "gradient")
+            procedure.add_argument_from_property(self, "file")
+        return procedure
+
+Gimp.main(GradientsSaveAsCSS.__gtype__, sys.argv)
diff --git a/plug-ins/python/meson.build b/plug-ins/python/meson.build
index f6e90e46af..56790e6f6f 100644
--- a/plug-ins/python/meson.build
+++ b/plug-ins/python/meson.build
@@ -3,13 +3,13 @@ if have_python
 plugins = [
   { 'name': 'file-openraster' },
   { 'name': 'foggify' },
+  { 'name': 'gradients-save-as-css' },
   { 'name': 'palette-offset' },
   { 'name': 'palette-to-gradient' },
   { 'name': 'py-slice' },
   { 'name': 'spyro-plus' },
 
   # { 'name': 'colorxhtml' },
-  # { 'name': 'gradients-save-as-css' },
   # { 'name': 'histogram-export' },
   # { 'name': 'palette-sort' },
   # { 'name': 'python-eval' },