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.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1630>

diff --git a/src/st/st-scroll-view-fade.c b/src/st/st-scroll-view-fade.c
index 3ca73133729b7069c6b0d22f8e83fdd404ec8a1c..b387e384a56883ed467dbe93023c21bb504b947e 100644 (file)
--- 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));