[gimp] app: add custom gui for gegl:color-to-alpha(-plus)

[N/A <ell src gnome org>]

commit d4d8dbbc1b24306692514308d67cd2d4bfda1a12
Author: Ell <ell_se yahoo com>
Date:   Mon Oct 16 11:47:43 2017 -0400

    app: add custom gui for gegl:color-to-alpha(-plus)
    
    Add a specialized propgui constructor for gegl:color-to-alpha-plus.
    This op is currently in the workshop, but is set to be merged with
    the existing gegl:color-to-alpha, so we omit the '-plus' from file-
    and function-names.
    
    The new op adds a pair of properties to control the radii, relative
    to the selected color, below which colors become fully transparent,
    and above which colors remain fully opaque.  Allow these properties
    to be set by picking a color from the image, and calculating the
    radius accordingly.

 app/propgui/Makefile.am                  |    2 +
 app/propgui/gimppropgui-color-to-alpha.c |  148 ++++++++++++++++++++++++++++++
 app/propgui/gimppropgui-color-to-alpha.h |   35 +++++++
 app/propgui/gimppropgui.c                |    3 +
 po/POTFILES.in                           |    1 +
 5 files changed, 189 insertions(+), 0 deletions(-)
---
diff --git a/app/propgui/Makefile.am b/app/propgui/Makefile.am
index 2aee896..e94e9eb 100644
--- a/app/propgui/Makefile.am
+++ b/app/propgui/Makefile.am
@@ -25,6 +25,8 @@ libapppropgui_a_SOURCES = \
        gimppropgui-color-balance.h             \
        gimppropgui-color-rotate.c              \
        gimppropgui-color-rotate.h              \
+       gimppropgui-color-to-alpha.c            \
+       gimppropgui-color-to-alpha.h            \
        gimppropgui-convolution-matrix.c        \
        gimppropgui-convolution-matrix.h        \
        gimppropgui-diffraction-patterns.c      \
diff --git a/app/propgui/gimppropgui-color-to-alpha.c b/app/propgui/gimppropgui-color-to-alpha.c
new file mode 100644
index 0000000..af47297
--- /dev/null
+++ b/app/propgui/gimppropgui-color-to-alpha.c
@@ -0,0 +1,148 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995-1997 Spencer Kimball and Peter Mattis
+ *
+ * gimppropgui-color-to-alpha.c
+ * Copyright (C) 2017 Ell
+ *
+ * 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 "config.h"
+
+#include <gegl.h>
+#include <gtk/gtk.h>
+
+#include "libgimpmath/gimpmath.h"
+#include "libgimpwidgets/gimpwidgets.h"
+
+#include "propgui-types.h"
+
+#include "core/gimpcontext.h"
+
+#include "gimppropgui.h"
+#include "gimppropgui-color-to-alpha.h"
+#include "gimppropgui-generic.h"
+
+#include "gimp-intl.h"
+
+
+static void
+threshold_picked (GObject       *config,
+                  gpointer       identifier,
+                  gdouble        x,
+                  gdouble        y,
+                  const Babl    *sample_format,
+                  const GimpRGB *color)
+{
+  GimpRGB *bg_color;
+  gdouble  radius        = 0.0;
+  gdouble  target_radius = 0.0;
+  gdouble  threshold;
+
+  g_object_get (config,
+                "color", &bg_color,
+                NULL);
+
+  radius = MAX (radius, MAX (bg_color->r, 1.0 - bg_color->r));
+  radius = MAX (radius, MAX (bg_color->g, 1.0 - bg_color->g));
+  radius = MAX (radius, MAX (bg_color->b, 1.0 - bg_color->b));
+
+  target_radius = MAX (target_radius, fabs (color->r - bg_color->r));
+  target_radius = MAX (target_radius, fabs (color->g - bg_color->g));
+  target_radius = MAX (target_radius, fabs (color->b - bg_color->b));
+
+  threshold = target_radius / radius;
+
+  g_object_set (config,
+                identifier, threshold,
+                NULL);
+
+  g_free (bg_color);
+}
+
+GtkWidget *
+_gimp_prop_gui_new_color_to_alpha (GObject                  *config,
+                                   GParamSpec              **param_specs,
+                                   guint                     n_param_specs,
+                                   GeglRectangle            *area,
+                                   GimpContext              *context,
+                                   GimpCreatePickerFunc      create_picker_func,
+                                   GimpCreateControllerFunc  create_controller_func,
+                                   gpointer                  creator)
+{
+  GtkWidget   *vbox;
+  GtkWidget   *button;
+  GtkWidget   *hbox;
+  GtkWidget   *scale;
+  const gchar *label;
+
+  g_return_val_if_fail (G_IS_OBJECT (config), NULL);
+  g_return_val_if_fail (param_specs != NULL, NULL);
+  g_return_val_if_fail (n_param_specs > 0, NULL);
+  g_return_val_if_fail (GIMP_IS_CONTEXT (context), NULL);
+
+  vbox = gtk_box_new (GTK_ORIENTATION_VERTICAL, 4);
+
+  button = _gimp_prop_gui_new_generic (config, param_specs, 1,
+                                       area, context, create_picker_func, NULL,
+                                       creator);
+  gtk_box_pack_start (GTK_BOX (vbox), button, FALSE, FALSE, 0);
+  gtk_widget_show (button);
+
+  hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 4);
+  gtk_box_pack_start (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);
+  gtk_widget_show (hbox);
+
+  scale = gimp_prop_widget_new (config, "transparency-threshold",
+                                area, context, NULL, NULL, NULL, &label);
+  gtk_box_pack_start (GTK_BOX (hbox), scale, TRUE, TRUE, 0);
+  gtk_widget_show (scale);
+
+  if (create_picker_func)
+    {
+      button = create_picker_func (creator,
+                                   "transparency-threshold",
+                                   GIMP_ICON_COLOR_PICKER_GRAY,
+                                   _("Pick farthest full-transparency color"),
+                                   /* pick_abyss = */ FALSE,
+                                   (GimpPickerCallback) threshold_picked,
+                                   config);
+      gtk_box_pack_start (GTK_BOX (hbox), button, FALSE, FALSE, 0);
+      gtk_widget_show (button);
+    }
+
+  hbox = gtk_box_new (GTK_ORIENTATION_HORIZONTAL, 4);
+  gtk_box_pack_start (GTK_BOX (vbox), hbox, FALSE, FALSE, 0);
+  gtk_widget_show (hbox);
+
+  scale = gimp_prop_widget_new (config, "opacity-threshold",
+                                area, context, NULL, NULL, NULL, &label);
+  gtk_box_pack_start (GTK_BOX (hbox), scale, TRUE, TRUE, 0);
+  gtk_widget_show (scale);
+
+  if (create_picker_func)
+    {
+      button = create_picker_func (creator,
+                                   "opacity-threshold",
+                                   GIMP_ICON_COLOR_PICKER_GRAY,
+                                   _("Pick nearest full-opacity color"),
+                                   /* pick_abyss = */ FALSE,
+                                   (GimpPickerCallback) threshold_picked,
+                                   config);
+      gtk_box_pack_start (GTK_BOX (hbox), button, FALSE, FALSE, 0);
+      gtk_widget_show (button);
+    }
+
+  return vbox;
+}
diff --git a/app/propgui/gimppropgui-color-to-alpha.h b/app/propgui/gimppropgui-color-to-alpha.h
new file mode 100644
index 0000000..67e225b
--- /dev/null
+++ b/app/propgui/gimppropgui-color-to-alpha.h
@@ -0,0 +1,35 @@
+/* GIMP - The GNU Image Manipulation Program
+ * Copyright (C) 1995-1997 Spencer Kimball and Peter Mattis
+ *
+ * gimppropgui-color-to-alpha.h
+ *
+ * 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/>.
+ */
+
+#ifndef __GIMP_PROP_GUI_COLOR_TO_ALPHA_H__
+#define __GIMP_PROP_GUI_COLOR_TO_ALPHA_H__
+
+
+GtkWidget *
+_gimp_prop_gui_new_color_to_alpha (GObject                  *config,
+                                   GParamSpec              **param_specs,
+                                   guint                     n_param_specs,
+                                   GeglRectangle            *area,
+                                   GimpContext              *context,
+                                   GimpCreatePickerFunc      create_picker_func,
+                                   GimpCreateControllerFunc  create_controller_func,
+                                   gpointer                  creator);
+
+
+#endif /* __GIMP_PROP_GUI_COLOR_TO_ALPHA_H__ */
diff --git a/app/propgui/gimppropgui.c b/app/propgui/gimppropgui.c
index d9ad874..586c176 100644
--- a/app/propgui/gimppropgui.c
+++ b/app/propgui/gimppropgui.c
@@ -48,6 +48,7 @@
 #include "gimppropgui-channel-mixer.h"
 #include "gimppropgui-color-balance.h"
 #include "gimppropgui-color-rotate.h"
+#include "gimppropgui-color-to-alpha.h"
 #include "gimppropgui-convolution-matrix.h"
 #include "gimppropgui-diffraction-patterns.h"
 #include "gimppropgui-eval.h"
@@ -435,6 +436,8 @@ gui_new_funcs[] =
     _gimp_prop_gui_new_hue_saturation },
   { "GimpGegl-gegl-color-rotate-config",
     _gimp_prop_gui_new_color_rotate },
+  { "GimpGegl-gegl-color-to-alpha-plus-config",
+    _gimp_prop_gui_new_color_to_alpha },
   { "GimpGegl-gegl-convolution-matrix-config",
     _gimp_prop_gui_new_convolution_matrix },
   { "GimpGegl-gegl-channel-mixer-config",
diff --git a/po/POTFILES.in b/po/POTFILES.in
index 9745ec3..961b14a 100644
--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -372,6 +372,7 @@ app/plug-in/plug-in-rc.c
 app/propgui/gimppropgui-channel-mixer.c
 app/propgui/gimppropgui-color-balance.c
 app/propgui/gimppropgui-color-rotate.c
+app/propgui/gimppropgui-color-to-alpha.c
 app/propgui/gimppropgui-convolution-matrix.c
 app/propgui/gimppropgui-diffraction-patterns.c
 app/propgui/gimppropgui-generic.c