[gnome-shell] scroll-view-fade: Tweak easing at edges

[Florian Müllner <fmuellner src gnome org>]

commit b394d184cc7fa68924da7e4c57ba9d2eb84c97ef
Author: Florian Müllner <fmuellner gnome org>
Date:   Sat Feb 23 01:37:05 2013 +0100

    scroll-view-fade: Tweak easing at edges
    
    Since commit b4f5f1e46174, the effect is eased in at the scroll
    view's edges so that it does not appear out of nowhere. However,
    the linear easing used is not the best option, as now the effect
    appears so late that content near the edges ends up just being
    cut off rather than faded out.
    So adjust the easing function to have the effect appear faster.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=694327

 src/st/st-scroll-view-fade.glsl |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)
---
diff --git a/src/st/st-scroll-view-fade.glsl b/src/st/st-scroll-view-fade.glsl
index 6acd260..e8bd03a 100644
--- a/src/st/st-scroll-view-fade.glsl
+++ b/src/st/st-scroll-view-fade.glsl
@@ -64,20 +64,20 @@ void main ()
 
     float vfade_scale = height / vfade_offset;
     if (fade_top) {
-        ratio *= FADE((y / vfade_offset), min(vvalue * vfade_scale, 1.0));
+        ratio *= FADE((y / vfade_offset), min(sqrt(vvalue) * vfade_scale, 1.0));
     }
 
     if (fade_bottom) {
-        ratio *= FADE((fade_area[1][1] - y)/(fade_area[1][1] - fade_bottom_start), min((1.0 - vvalue) * 
vfade_scale, 1.0));
+        ratio *= FADE((fade_area[1][1] - y)/(fade_area[1][1] - fade_bottom_start), min(sqrt(1.0 - vvalue) * 
vfade_scale, 1.0));
     }
 
     float hfade_scale = width / hfade_offset;
     if (fade_left) {
-        ratio *= FADE(x / hfade_offset, min(hvalue * hfade_scale, 1.0));
+        ratio *= FADE(x / hfade_offset, min(sqrt(hvalue) * hfade_scale, 1.0));
     }
 
     if (fade_right) {
-        ratio *= FADE((fade_area[1][0] - x)/(fade_area[1][0] - fade_right_start), min((1.0 - hvalue) * 
hfade_scale, 1.0));
+        ratio *= FADE((fade_area[1][0] - x)/(fade_area[1][0] - fade_right_start), min(sqrt(1.0 - hvalue) * 
hfade_scale, 1.0));
     }
 
     cogl_color_out *= ratio;