[gnome-shell] scroll-view-fade: Adjust the effect to work in RTL locales

[Florian Müllner <fmuellner src gnome org>]

commit 63be52e1911d7852d092d776a9b175e56394d385
Author: Florian Müllner <fmuellner gnome org>
Date:   Thu Feb 24 02:16:07 2011 +0100

    scroll-view-fade: Adjust the effect to work in RTL locales
    
    The vertical scrollbar is located on the left in RTL locales, so
    pass an additional parameter to the shader which indicates the
    locale's text direction.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=643156

 src/st/st-scroll-view-fade.c |   11 +++++++++--
 1 files changed, 9 insertions(+), 2 deletions(-)
---
diff --git a/src/st/st-scroll-view-fade.c b/src/st/st-scroll-view-fade.c
index 58179fe..3d6639a 100644
--- a/src/st/st-scroll-view-fade.c
+++ b/src/st/st-scroll-view-fade.c
@@ -42,6 +42,7 @@ static const gchar *fade_glsl_shader =
 "uniform float scrollbar_width;\n"
 "uniform float offset_bottom;\n"
 "uniform float offset_top;\n"
+"uniform bool rtl;\n"
 "\n"
 "void main ()\n"
 "{\n"
@@ -51,11 +52,11 @@ static const gchar *fade_glsl_shader =
 " float ratio = 0.0;\n"
 " float fade_bottom_start = height - offset_bottom;\n"
 " \n"
-" if (offset_top != 0.0 && y < offset_top && x < (width - scrollbar_width)) {\n"
+" if (offset_top != 0.0 && y < offset_top && ((rtl && x > scrollbar_width) || (!rtl && x < (width - scrollbar_width)))) {\n"
 "  ratio = y / offset_top;\n"
 "  cogl_color_out = color * ratio;\n"
 " }\n"
-" else if (offset_bottom != 0.0 && y > fade_bottom_start && x < (width - scrollbar_width)) {\n"
+" else if (offset_bottom != 0.0 && y > fade_bottom_start && ((rtl && x > scrollbar_width) || (!rtl && x < (width - scrollbar_width)))) {\n"
 "  ratio = (height - y)/(height - fade_bottom_start);\n"
 "  cogl_color_out = color * ratio;\n"
 " }\n"
@@ -80,6 +81,7 @@ struct _StScrollViewFade
   gint scrollbar_width_uniform;
   gint offset_top_uniform;
   gint offset_bottom_uniform;
+  gint rtl_uniform;
 
   StAdjustment *vadjustment;
 
@@ -141,6 +143,8 @@ st_scroll_view_fade_pre_paint (ClutterEffect *effect)
         cogl_program_get_uniform_location (self->program, "width");
       self->scrollbar_width_uniform =
         cogl_program_get_uniform_location (self->program, "scrollbar_width");
+      self->rtl_uniform =
+        cogl_program_get_uniform_location (self->program, "rtl");
       self->offset_top_uniform =
         cogl_program_get_uniform_location (self->program, "offset_top");
       self->offset_bottom_uniform =
@@ -199,6 +203,8 @@ st_scroll_view_fade_paint_target (ClutterOffscreenEffect *effect)
     cogl_program_set_uniform_1f (self->program, self->width_uniform, clutter_actor_get_width (self->actor));
   if (self->scrollbar_width_uniform > -1)
     cogl_program_set_uniform_1f (self->program, self->scrollbar_width_uniform, clutter_actor_get_width (vscroll));
+  if (self->rtl_uniform > -1)
+    cogl_program_set_uniform_1i (self->program, self->rtl_uniform, (st_widget_get_direction (ST_WIDGET (self->actor)) == ST_TEXT_DIRECTION_RTL));
 
   material = clutter_offscreen_effect_get_target (effect);
   cogl_material_set_user_program (material, self->program);
@@ -408,6 +414,7 @@ st_scroll_view_fade_init (StScrollViewFade *self)
   self->height_uniform = -1;
   self->width_uniform = -1;
   self->scrollbar_width_uniform = -1;
+  self->rtl_uniform = -1;
   self->offset_top_uniform = -1;
   self->offset_bottom_uniform = -1;
   self->fade_offset = DEFAULT_FADE_OFFSET;