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

diff --git a/src/st/st-scroll-view-fade.c b/src/st/st-scroll-view-fade.c
index 58179fe8a5983af93244c92f8d76885bec153782..3d6639ae977e882695f0f10f465657522c056b46 100644 (file)
--- 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;