[gnome-shell] st: Add StScrollViewFade:fade-edges

[Florian Müllner <fmuellner src gnome org>]

commit 4f5d3e00dba57f048ac212915a34cabe40890e39
Author: Florian Müllner <fmuellner gnome org>
Date:   Wed Sep 4 17:53:41 2013 +0200

    st: Add StScrollViewFade:fade-edges
    
    Add a new property which controls whether edge areas are excluded
    from the effect (the default and current behavior), or not.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=707409

 src/st/st-scroll-view-fade.c    |   38 +++++++++++++++++++++++++++++++++++++-
 src/st/st-scroll-view-fade.glsl |   13 +++++++++----
 2 files changed, 46 insertions(+), 5 deletions(-)
---
diff --git a/src/st/st-scroll-view-fade.c b/src/st/st-scroll-view-fade.c
index 202897d..71ad3ce 100644
--- a/src/st/st-scroll-view-fade.c
+++ b/src/st/st-scroll-view-fade.c
@@ -49,6 +49,8 @@ struct _StScrollViewFade
   StAdjustment *vadjustment;
   StAdjustment *hadjustment;
 
+  guint fade_edges : 1;
+
   float vfade_offset;
   float hfade_offset;
 };
@@ -66,7 +68,8 @@ enum {
   PROP_0,
 
   PROP_VFADE_OFFSET,
-  PROP_HFADE_OFFSET
+  PROP_HFADE_OFFSET,
+  PROP_FADE_EDGES
 };
 
 static CoglHandle
@@ -151,6 +154,7 @@ st_scroll_view_fade_paint_target (ClutterOffscreenEffect *effect)
   clutter_shader_effect_set_uniform (shader, "tex", G_TYPE_INT, 1, 0);
   clutter_shader_effect_set_uniform (shader, "height", G_TYPE_FLOAT, 1, clutter_actor_get_height 
(self->actor));
   clutter_shader_effect_set_uniform (shader, "width", G_TYPE_FLOAT, 1, clutter_actor_get_width 
(self->actor));
+  clutter_shader_effect_set_uniform (shader, "fade_edges", G_TYPE_INT, 1, self->fade_edges);
   clutter_shader_effect_set_uniform (shader, "fade_area_topleft", CLUTTER_TYPE_SHADER_FLOAT, 2, 
fade_area_topleft);
   clutter_shader_effect_set_uniform (shader, "fade_area_bottomright", CLUTTER_TYPE_SHADER_FLOAT, 2, 
fade_area_bottomright);
 
@@ -293,6 +297,24 @@ st_scroll_view_hfade_set_offset (StScrollViewFade *self,
 }
 
 static void
+st_scroll_view_fade_set_fade_edges (StScrollViewFade *self,
+                                    gboolean          fade_edges)
+{
+  if (self->fade_edges == fade_edges)
+    return;
+
+  g_object_freeze_notify (G_OBJECT (self));
+
+  self->fade_edges = fade_edges;
+
+  if (self->actor != NULL)
+    clutter_actor_queue_redraw (self->actor);
+
+  g_object_notify (G_OBJECT (self), "fade-edges");
+  g_object_thaw_notify (G_OBJECT (self));
+}
+
+static void
 st_scroll_view_fade_set_property (GObject *object,
                                   guint prop_id,
                                   const GValue *value,
@@ -308,6 +330,9 @@ st_scroll_view_fade_set_property (GObject *object,
     case PROP_HFADE_OFFSET:
       st_scroll_view_hfade_set_offset (self, g_value_get_float (value));
       break;
+    case PROP_FADE_EDGES:
+      st_scroll_view_fade_set_fade_edges (self, g_value_get_boolean (value));
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -330,6 +355,9 @@ st_scroll_view_fade_get_property (GObject *object,
     case PROP_VFADE_OFFSET:
       g_value_set_float (value, self->vfade_offset);
       break;
+    case PROP_FADE_EDGES:
+      g_value_set_boolean (value, self->fade_edges);
+      break;
     default:
       G_OBJECT_WARN_INVALID_PROPERTY_ID (object, prop_id, pspec);
       break;
@@ -371,6 +399,14 @@ st_scroll_view_fade_class_init (StScrollViewFadeClass *klass)
                                                        "The width of the area which is faded at the edge",
                                                        0.f, G_MAXFLOAT, DEFAULT_FADE_OFFSET,
                                                        G_PARAM_READWRITE));
+  g_object_class_install_property (gobject_class,
+                                   PROP_FADE_EDGES,
+                                   g_param_spec_boolean ("fade-edges",
+                                                         "Fade Edges",
+                                                         "Whether the faded area should extend to the edges",
+                                                         FALSE,
+                                                         G_PARAM_READWRITE));
+
 
 }
 
diff --git a/src/st/st-scroll-view-fade.glsl b/src/st/st-scroll-view-fade.glsl
index 810adcd..629c014 100644
--- a/src/st/st-scroll-view-fade.glsl
+++ b/src/st/st-scroll-view-fade.glsl
@@ -24,6 +24,7 @@ uniform float vfade_offset;
 uniform float hfade_offset;
 uniform float vvalue;
 uniform float hvalue;
+uniform bool  fade_edges;
 
 uniform vec2 fade_area_topleft;
 uniform vec2 fade_area_bottomright;
@@ -44,10 +45,14 @@ void main ()
         float ratio = 1.0;
         float fade_bottom_start = fade_area_bottomright[1] - vfade_offset;
         float fade_right_start = fade_area_bottomright[0] - hfade_offset;
-        bool fade_top = y < vfade_offset && vvalue > 0.0;
-        bool fade_bottom = y > fade_bottom_start && vvalue < 1.0;
-        bool fade_left = x < hfade_offset && hvalue > 0.0;
-        bool fade_right = x > fade_right_start && hvalue < 1.0;
+        bool fade_top = y < vfade_offset && (fade_edges ? vvalue >= 0.0
+                                                        : vvalue > 0.0);
+        bool fade_bottom = y > fade_bottom_start && (fade_edges ? vvalue <= 1.0
+                                                                : vvalue < 1.0);
+        bool fade_left = x < hfade_offset && (fade_edges ? hvalue >= 0.0
+                                                         : hvalue > 0.0);
+        bool fade_right = x > fade_right_start && (fade_edges ? hvalue <= 1.0
+                                                              : hvalue < 1.0);
 
         float vfade_scale = height / vfade_offset;
         if (fade_top) {