st/theme-node-drawing: Render box-shadow independently of background-color

Until now, the absence of a `background-color` would cause `box-shadow`s
to be invisible. That was a bug because `box-shadow` is meant to be either
the color specified in `box-shadow`, or if none was specified then the
foreground `color`.

There is nothing in the spec that says the `box-shadow` rendering should
depend on `background-color`, so separate them. This ensures `box-shadow`
is rendered even when `background-color` is absent or transparent.

https://www.w3.org/TR/css-backgrounds-3/#box-shadow

Part-of: <https://gitlab.gnome.org/GNOME/gnome-shell/-/merge_requests/1904>
This commit is contained in:
Daniel van Vugt 2021-05-27 17:12:15 +08:00 committed by Marge Bot
parent 82450e1060
commit 6721710932

View File

@ -51,6 +51,11 @@ typedef struct {
float resource_scale;
} StCornerSpec;
typedef enum {
ST_PAINT_BORDERS_MODE_COLOR,
ST_PAINT_BORDERS_MODE_SILHOUETTE
} StPaintBordersMode;
static void
elliptical_arc (cairo_t *cr,
double x_center,
@ -409,7 +414,12 @@ st_theme_node_lookup_corner (StThemeNode *node,
if (corner.color.alpha == 0 &&
corner.border_color_1.alpha == 0 &&
corner.border_color_2.alpha == 0)
return NULL;
{
if (node->box_shadow == NULL)
return NULL;
else /* We still need a corner texture to render the box-shadow */
corner.color = (ClutterColor) {0, 0, 0, 255};
}
key = corner_to_string (&corner);
texture = st_texture_cache_load (cache, key, ST_TEXTURE_CACHE_POLICY_FOREVER, load_corner, &corner, NULL);
@ -1355,6 +1365,7 @@ st_theme_node_prerender_background (StThemeNode *node,
static void st_theme_node_paint_borders (StThemeNodePaintState *state,
CoglFramebuffer *framebuffer,
const ClutterActorBox *box,
StPaintBordersMode mode,
guint8 paint_opacity);
void
@ -1580,7 +1591,7 @@ st_theme_node_render_resources (StThemeNodePaintState *state,
state->box_shadow_pipeline = _st_create_shadow_pipeline (box_shadow_spec,
state->prerendered_texture,
state->resource_scale);
else if (node->background_color.alpha > 0 || has_border)
else
st_theme_node_prerender_shadow (state);
}
@ -1697,6 +1708,7 @@ static void
st_theme_node_paint_borders (StThemeNodePaintState *state,
CoglFramebuffer *framebuffer,
const ClutterActorBox *box,
StPaintBordersMode mode,
guint8 paint_opacity)
{
StThemeNode *node = state->node;
@ -1708,6 +1720,7 @@ st_theme_node_paint_borders (StThemeNodePaintState *state,
int corner_id, side_id;
ClutterColor border_color;
guint8 alpha;
gboolean corners_are_transparent;
width = box->x2 - box->x1;
height = box->y2 - box->y1;
@ -1802,8 +1815,12 @@ st_theme_node_paint_borders (StThemeNodePaintState *state,
}
}
corners_are_transparent = mode == ST_PAINT_BORDERS_MODE_COLOR &&
node->background_color.alpha == 0 &&
node->border_color[0].alpha == 0;
/* corners */
if (max_border_radius > 0 && paint_opacity > 0)
if (max_border_radius > 0 && paint_opacity > 0 && !corners_are_transparent)
{
for (corner_id = 0; corner_id < 4; corner_id++)
{
@ -1852,7 +1869,9 @@ st_theme_node_paint_borders (StThemeNodePaintState *state,
}
/* background color */
alpha = paint_opacity * node->background_color.alpha / 255;
alpha = mode == ST_PAINT_BORDERS_MODE_SILHOUETTE ?
255 :
paint_opacity * node->background_color.alpha / 255;
if (alpha > 0)
{
st_theme_node_ensure_color_pipeline (node);
@ -2307,7 +2326,7 @@ st_theme_node_prerender_shadow (StThemeNodePaintState *state)
state->resource_scale, 1);
cogl_framebuffer_clear4f (framebuffer, COGL_BUFFER_BIT_COLOR, 0, 0, 0, 0);
st_theme_node_paint_borders (state, framebuffer, &box, 0xFF);
st_theme_node_paint_borders (state, framebuffer, &box, ST_PAINT_BORDERS_MODE_SILHOUETTE, 0xFF);
state->box_shadow_pipeline = _st_create_shadow_pipeline (st_theme_node_get_box_shadow (node),
buffer, state->resource_scale);
@ -2663,7 +2682,7 @@ st_theme_node_paint (StThemeNode *node,
}
else
{
st_theme_node_paint_borders (state, framebuffer, box, paint_opacity);
st_theme_node_paint_borders (state, framebuffer, box, ST_PAINT_BORDERS_MODE_COLOR, paint_opacity);
}
st_theme_node_paint_outline (node, framebuffer, box, paint_opacity);