st/theme-node-drawing: Conditionally paint the center shadow rectangle

Only when part of it is actually visible.

Because the central rectangle is generally the largest part, this
eliminates most of the shadow's render time. For example, animating
`.workspace-background` by tapping Super, the shell's overall render
time is reduced about 15%.

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1915>
This commit is contained in:
Daniel van Vugt 2021-05-25 17:33:01 +08:00 committed by Marge Bot
parent 436fd81cfc
commit 9b3ee774f6

View File

@ -2021,6 +2021,8 @@ st_theme_node_paint_sliced_shadow (StThemeNodePaintState *state,
gfloat shadow_blur_radius, x_spread_factor, y_spread_factor;
float rectangles[8 * 9];
gint idx;
ClutterColor background_color;
static const ClutterColor invisible_occluded = {3, 2, 1, 0};
if (paint_opacity == 0)
return;
@ -2178,7 +2180,13 @@ st_theme_node_paint_sliced_shadow (StThemeNodePaintState *state,
rectangles[idx++] = s_bottom;
}
/* Center middle */
/* Center middle is not definitely occluded? */
st_theme_node_get_background_color (node, &background_color);
if (!clutter_color_equal (&background_color, &invisible_occluded) ||
paint_opacity < 255 ||
xoffset > shadow_blur_radius || left < 0 ||
yoffset > shadow_blur_radius || top < 0)
{
rectangles[idx++] = left;
rectangles[idx++] = top;
rectangles[idx++] = right;
@ -2188,6 +2196,7 @@ st_theme_node_paint_sliced_shadow (StThemeNodePaintState *state,
rectangles[idx++] = s_top;
rectangles[idx++] = s_right;
rectangles[idx++] = s_bottom;
}
if (xend > right)
{