[gnome-shell/wip/carlosg/appgrid-navigation] st/scrollview: Apply correct fade_edges_left/right effect uniforms in RTL

[Carlos Garnacho <carlosg src gnome org>]

commit 272bd2a38d1e67e5100358e8bc00c7fb4c8573cb
Author: Carlos Garnacho <carlosg gnome org>
Date:   Sat Feb 27 20:23:19 2021 +0100

    st/scrollview: Apply correct fade_edges_left/right effect uniforms in RTL
    
    When the setting is false, we apply anyway depending on the adjustment
    value. Look for the right value corresponding to that side as per the
    locale.

 src/st/st-scroll-view-fade.c | 13 ++++++++++---
 1 file changed, 10 insertions(+), 3 deletions(-)
---
diff --git a/src/st/st-scroll-view-fade.c b/src/st/st-scroll-view-fade.c
index 3ca7313372..b387e384a5 100644
--- a/src/st/st-scroll-view-fade.c
+++ b/src/st/st-scroll-view-fade.c
@@ -94,7 +94,7 @@ st_scroll_view_fade_paint_target (ClutterOffscreenEffect *effect,
   gdouble value, lower, upper, page_size;
   ClutterActor *vscroll = st_scroll_view_get_vscroll_bar (ST_SCROLL_VIEW (self->actor));
   ClutterActor *hscroll = st_scroll_view_get_hscroll_bar (ST_SCROLL_VIEW (self->actor));
-  gboolean h_scroll_visible, v_scroll_visible;
+  gboolean h_scroll_visible, v_scroll_visible, rtl;
 
   ClutterActorBox allocation, content_box, paint_box;
   ClutterMargin *content_padding;
@@ -158,8 +158,15 @@ st_scroll_view_fade_paint_target (ClutterOffscreenEffect *effect,
 
   st_adjustment_get_values (self->hadjustment, &value, &lower, &upper, NULL, NULL, &page_size);
   value = (value - lower) / (upper - page_size - lower);
-  clutter_shader_effect_set_uniform (shader, "fade_edges_left", G_TYPE_INT, 1, self->fade_edges ? value >= 
0.0 : value > 0.0);
-  clutter_shader_effect_set_uniform (shader, "fade_edges_right", G_TYPE_INT, 1, self->fade_edges ? value <= 
1.0 : value < 1.0);
+  rtl = clutter_actor_get_text_direction (self->actor) == CLUTTER_TEXT_DIRECTION_RTL;
+  clutter_shader_effect_set_uniform (shader, "fade_edges_left", G_TYPE_INT, 1,
+                                     self->fade_edges ?
+                                     value >= 0.0 :
+                                     (rtl ? value < 1.0 : value > 0.0));
+  clutter_shader_effect_set_uniform (shader, "fade_edges_right", G_TYPE_INT, 1,
+                                     self->fade_edges ?
+                                     value <= 1.0 :
+                                     (rtl ? value > 0.0 : value < 1.0));
 
   clutter_shader_effect_set_uniform (shader, "fade_offset_top", G_TYPE_FLOAT, 1, ABS 
(self->fade_margins.top));
   clutter_shader_effect_set_uniform (shader, "fade_offset_bottom", G_TYPE_FLOAT, 1, ABS 
(self->fade_margins.bottom));