[libpanel] progress-icon: add simplified PanelProgressIcon

[Christian Hergert <chergert src gnome org>]

commit ba605025acaa43832737b7ca50342bb6c9e590c4
Author: Christian Hergert <chergert redhat com>
Date:   Tue Sep 13 13:49:11 2022 -0700

    progress-icon: add simplified PanelProgressIcon
    
    This just draws the typical circle/pie we're used to from Nautilus. It
    uses the accent color though for progress since using black will be a
    bit harsh for it's use (in the save dialog).

 src/meson.build                   |   1 +
 src/panel-progress-icon-private.h |  36 ++++++++
 src/panel-progress-icon.c         | 180 ++++++++++++++++++++++++++++++++++++++
 src/stylesheet.css                |   4 +
 4 files changed, 221 insertions(+)
---
diff --git a/src/meson.build b/src/meson.build
index 8ff43ce..4884b3a 100644
--- a/src/meson.build
+++ b/src/meson.build
@@ -26,6 +26,7 @@ libpanel_private_sources = [
   'panel-handle.c',
   'panel-joined-menu.c',
   'panel-maximized-controls.c',
+  'panel-progress-icon.c',
   'panel-resizer.c',
   'panel-save-dialog-row.c',
   'panel-scaler.c',
diff --git a/src/panel-progress-icon-private.h b/src/panel-progress-icon-private.h
new file mode 100644
index 0000000..f86c99a
--- /dev/null
+++ b/src/panel-progress-icon-private.h
@@ -0,0 +1,36 @@
+/* panel-progress-icon-private.h
+ *
+ * Copyright 2022 Christian Hergert <chergert redhat com>
+ *
+ * This file is free software; you can redistribute it and/or modify it under
+ * the terms of the GNU Lesser General Public License as published by the Free
+ * Software Foundation; either version 3 of the License, or (at your option)
+ * any later version.
+ *
+ * This file 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 Lesser 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/>.
+ *
+ * SPDX-License-Identifier: LGPL-3.0-or-later
+ */
+
+#pragma once
+
+#include <gtk/gtk.h>
+
+G_BEGIN_DECLS
+
+#define PANEL_TYPE_PROGRESS_ICON (panel_progress_icon_get_type())
+
+G_DECLARE_FINAL_TYPE (PanelProgressIcon, panel_progress_icon, PANEL, PROGRESS_ICON, GtkDrawingArea)
+
+GtkWidget *panel_progress_icon_new          (void);
+gdouble    panel_progress_icon_get_progress (PanelProgressIcon *self);
+void       panel_progress_icon_set_progress (PanelProgressIcon *self,
+                                             double             progress);
+
+G_END_DECLS
diff --git a/src/panel-progress-icon.c b/src/panel-progress-icon.c
new file mode 100644
index 0000000..1338bae
--- /dev/null
+++ b/src/panel-progress-icon.c
@@ -0,0 +1,180 @@
+/* panel-progress-icon.c
+ *
+ * Copyright 2022 Christian Hergert <chergert redhat com>
+ *
+ * This file is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU Lesser General Public License as
+ * published by the Free Software Foundation; either version 3 of the
+ * License, or (at your option) any later version.
+ *
+ * This file 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
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ *
+ * SPDX-License-Identifier: LGPL-3.0-or-later
+ */
+
+#include "config.h"
+
+#include "panel-progress-icon-private.h"
+
+struct _PanelProgressIcon
+{
+  GtkDrawingArea parent_instance;
+  double         progress;
+};
+
+G_DEFINE_FINAL_TYPE (PanelProgressIcon, panel_progress_icon, GTK_TYPE_DRAWING_AREA)
+
+enum {
+  PROP_0,
+  PROP_PROGRESS,
+  N_PROPS
+};
+
+static GParamSpec *properties [N_PROPS];
+
+static void
+panel_progress_icon_draw (GtkDrawingArea *area,
+                          cairo_t        *cr,
+                          int             width,
+                          int             height,
+                          gpointer        user_data)
+{
+  PanelProgressIcon *self = (PanelProgressIcon *)area;
+  GtkStyleContext *style_context;
+  GdkRGBA rgba;
+  double alpha;
+
+  g_assert (PANEL_IS_PROGRESS_ICON (self));
+  g_assert (cr != NULL);
+
+  style_context = gtk_widget_get_style_context (GTK_WIDGET (area));
+  gtk_style_context_get_color (style_context, &rgba);
+
+  alpha = rgba.alpha;
+  rgba.alpha = 0.15;
+  gdk_cairo_set_source_rgba (cr, &rgba);
+
+  cairo_arc (cr, width/2, height/2, width/2, .0, 2*G_PI);
+  cairo_fill (cr);
+
+  if (self->progress > .0)
+    {
+      rgba.alpha = alpha;
+      gdk_cairo_set_source_rgba (cr, &rgba);
+
+      cairo_arc (cr, width/2, height/2, width/2, (-.5*G_PI), (self->progress*2*G_PI) - (.5*G_PI));
+
+      if (self->progress != 1.0)
+        {
+          cairo_line_to (cr, width/2, height/2);
+          cairo_line_to (cr, width/2, 0);
+        }
+
+      cairo_fill (cr);
+    }
+}
+
+static void
+panel_progress_icon_get_property (GObject    *object,
+                                  guint       prop_id,
+                                  GValue     *value,
+                                  GParamSpec *pspec)
+{
+  PanelProgressIcon *self = PANEL_PROGRESS_ICON (object);
+
+  switch (prop_id)
+    {
+    case PROP_PROGRESS:
+      g_value_set_double (value, panel_progress_icon_get_progress (self));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+panel_progress_icon_set_property (GObject      *object,
+                                  guint         prop_id,
+                                  const GValue *value,
+                                  GParamSpec   *pspec)
+{
+  PanelProgressIcon *self = PANEL_PROGRESS_ICON (object);
+
+  switch (prop_id)
+    {
+    case PROP_PROGRESS:
+      panel_progress_icon_set_progress (self, g_value_get_double (value));
+      break;
+
+    default:
+      G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
+    }
+}
+
+static void
+panel_progress_icon_class_init (PanelProgressIconClass *klass)
+{
+  GObjectClass *object_class = G_OBJECT_CLASS (klass);
+  GtkWidgetClass *widget_class = GTK_WIDGET_CLASS (klass);
+
+  object_class->get_property = panel_progress_icon_get_property;
+  object_class->set_property = panel_progress_icon_set_property;
+
+  properties [PROP_PROGRESS] =
+    g_param_spec_double ("progress", NULL, NULL,
+                         0.0, 1.0, 0.0,
+                         (G_PARAM_READWRITE | G_PARAM_EXPLICIT_NOTIFY | G_PARAM_STATIC_STRINGS));
+
+  g_object_class_install_properties (object_class, N_PROPS, properties);
+
+  gtk_widget_class_set_css_name (widget_class, "panelprogressicon");
+}
+
+static void
+panel_progress_icon_init (PanelProgressIcon *icon)
+{
+  gtk_widget_set_size_request (GTK_WIDGET (icon), 16, 16);
+  gtk_widget_set_valign (GTK_WIDGET (icon), GTK_ALIGN_CENTER);
+  gtk_widget_set_halign (GTK_WIDGET (icon), GTK_ALIGN_CENTER);
+
+  gtk_drawing_area_set_draw_func (GTK_DRAWING_AREA (icon),
+                                  panel_progress_icon_draw,
+                                  NULL, NULL);
+}
+
+GtkWidget *
+panel_progress_icon_new (void)
+{
+  return g_object_new (PANEL_TYPE_PROGRESS_ICON, NULL);
+}
+
+double
+panel_progress_icon_get_progress (PanelProgressIcon *self)
+{
+  g_return_val_if_fail (PANEL_IS_PROGRESS_ICON (self), 0.0);
+
+  return self->progress;
+}
+
+void
+panel_progress_icon_set_progress (PanelProgressIcon *self,
+                                  double          progress)
+{
+  g_return_if_fail (PANEL_IS_PROGRESS_ICON (self));
+
+  progress = CLAMP (progress, 0.0, 1.0);
+
+  if (self->progress != progress)
+    {
+      self->progress = progress;
+      g_object_notify_by_pspec (G_OBJECT (self), properties [PROP_PROGRESS]);
+      gtk_widget_queue_draw (GTK_WIDGET (self));
+    }
+}
diff --git a/src/stylesheet.css b/src/stylesheet.css
index 09f92db..5f5e4b3 100644
--- a/src/stylesheet.css
+++ b/src/stylesheet.css
@@ -372,3 +372,7 @@ paneldropcontrols button:drop(active) {
   background-color: mix(@accent_bg_color, @accent_fg_color, .3);
   color: @theme_selected_fg_color;
 }
+
+panelprogressicon {
+  color: @accent_bg_color;
+}