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/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
use api::{BorderRadius, BoxShadowClipMode, ClipMode, ColorF, PrimitiveKeyKind};
use api::PropertyBinding;
use api::units::*;
use crate::clip::{ClipItemKey, ClipItemKeyKind, ClipNodeId};
use crate::scene_building::SceneBuilder;
use crate::spatial_tree::SpatialNodeIndex;
use crate::gpu_types::BoxShadowStretchMode;
use crate::render_task_graph::RenderTaskId;
use crate::internal_types::LayoutPrimitiveInfo;
#[derive(Debug, Clone, MallocSizeOf)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct BoxShadowClipSource {
// Parameters that define the shadow and are constant.
pub shadow_radius: BorderRadius,
pub blur_radius: f32,
pub clip_mode: BoxShadowClipMode,
pub stretch_mode_x: BoxShadowStretchMode,
pub stretch_mode_y: BoxShadowStretchMode,
// The current cache key (in device-pixels), and handles
// to the cached clip region and blurred texture.
pub cache_key: Option<(DeviceIntSize, BoxShadowCacheKey)>,
pub render_task: Option<RenderTaskId>,
// Local-space size of the required render task size.
pub shadow_rect_alloc_size: LayoutSize,
// Local-space size of the required render task size without any downscaling
// applied. This is needed to stretch the shadow properly.
pub original_alloc_size: LayoutSize,
// The minimal shadow rect for the parameters above,
// used when drawing the shadow rect to be blurred.
pub minimal_shadow_rect: LayoutRect,
// Local space rect for the shadow to be drawn or
// stretched in the shadow primitive.
pub prim_shadow_rect: LayoutRect,
}
// The blur shader samples BLUR_SAMPLE_SCALE * blur_radius surrounding texels.
pub const BLUR_SAMPLE_SCALE: f32 = 3.0;
// Maximum blur radius for box-shadows (different than blur filters).
// Taken from nsCSSRendering.cpp in Gecko.
pub const MAX_BLUR_RADIUS: f32 = 300.;
// A cache key that uniquely identifies a minimally sized
// and blurred box-shadow rect that can be stored in the
// texture cache and applied to clip-masks.
#[derive(Debug, Clone, Eq, Hash, MallocSizeOf, PartialEq)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct BoxShadowCacheKey {
pub blur_radius_dp: i32,
pub clip_mode: BoxShadowClipMode,
// NOTE(emilio): Only the original allocation size needs to be in the cache
// key, since the actual size is derived from that.
pub original_alloc_size: DeviceIntSize,
pub br_top_left: DeviceIntSize,
pub br_top_right: DeviceIntSize,
pub br_bottom_right: DeviceIntSize,
pub br_bottom_left: DeviceIntSize,
pub device_pixel_scale: Au,
}
impl<'a> SceneBuilder<'a> {
pub fn add_box_shadow(
&mut self,
spatial_node_index: SpatialNodeIndex,
clip_node_id: ClipNodeId,
prim_info: &LayoutPrimitiveInfo,
box_offset: &LayoutVector2D,
color: ColorF,
mut blur_radius: f32,
spread_radius: f32,
border_radius: BorderRadius,
clip_mode: BoxShadowClipMode,
) {
if color.a == 0.0 {
return;
}
// Inset shadows get smaller as spread radius increases.
let (spread_amount, prim_clip_mode) = match clip_mode {
BoxShadowClipMode::Outset => (spread_radius, ClipMode::ClipOut),
BoxShadowClipMode::Inset => (-spread_radius, ClipMode::Clip),
};
// Ensure the blur radius is somewhat sensible.
blur_radius = f32::min(blur_radius, MAX_BLUR_RADIUS);
// Adjust the border radius of the box shadow per CSS-spec.
let shadow_radius = adjust_border_radius_for_box_shadow(border_radius, spread_amount);
// Apply parameters that affect where the shadow rect
// exists in the local space of the primitive.
let shadow_rect = self.snap_rect(
&prim_info
.rect
.translate(*box_offset)
.inflate(spread_amount, spread_amount),
spatial_node_index,
);
// If blur radius is zero, we can use a fast path with
// no blur applied.
if blur_radius == 0.0 {
// Trivial reject of box-shadows that are not visible.
if box_offset.x == 0.0 && box_offset.y == 0.0 && spread_amount == 0.0 {
return;
}
let mut clips = Vec::with_capacity(2);
let (final_prim_rect, clip_radius) = match clip_mode {
BoxShadowClipMode::Outset => {
if shadow_rect.is_empty() {
return;
}
// TODO(gw): Add a fast path for ClipOut + zero border radius!
clips.push(ClipItemKey {
kind: ClipItemKeyKind::rounded_rect(
prim_info.rect,
border_radius,
ClipMode::ClipOut,
),
spatial_node_index,
});
(shadow_rect, shadow_radius)
}
BoxShadowClipMode::Inset => {
if !shadow_rect.is_empty() {
clips.push(ClipItemKey {
kind: ClipItemKeyKind::rounded_rect(
shadow_rect,
shadow_radius,
ClipMode::ClipOut,
),
spatial_node_index,
});
}
(prim_info.rect, border_radius)
}
};
clips.push(ClipItemKey {
kind: ClipItemKeyKind::rounded_rect(
final_prim_rect,
clip_radius,
ClipMode::Clip,
),
spatial_node_index,
});
self.add_primitive(
spatial_node_index,
clip_node_id,
&LayoutPrimitiveInfo::with_clip_rect(final_prim_rect, prim_info.clip_rect),
clips,
PrimitiveKeyKind::Rectangle {
color: PropertyBinding::Value(color.into()),
},
);
} else {
// Normal path for box-shadows with a valid blur radius.
let blur_offset = (BLUR_SAMPLE_SCALE * blur_radius).ceil();
let mut extra_clips = vec![];
// Add a normal clip mask to clip out the contents
// of the surrounding primitive.
extra_clips.push(ClipItemKey {
kind: ClipItemKeyKind::rounded_rect(
prim_info.rect,
border_radius,
prim_clip_mode,
),
spatial_node_index,
});
// Get the local rect of where the shadow will be drawn,
// expanded to include room for the blurred region.
let dest_rect = shadow_rect.inflate(blur_offset, blur_offset);
// Draw the box-shadow as a solid rect, using a box-shadow
// clip mask item.
let prim = PrimitiveKeyKind::Rectangle {
color: PropertyBinding::Value(color.into()),
};
// Create the box-shadow clip item.
let shadow_clip_source = ClipItemKey {
kind: ClipItemKeyKind::box_shadow(
shadow_rect,
shadow_radius,
dest_rect,
blur_radius,
clip_mode,
),
spatial_node_index,
};
let prim_info = match clip_mode {
BoxShadowClipMode::Outset => {
// Certain spread-radii make the shadow invalid.
if shadow_rect.is_empty() {
return;
}
// Add the box-shadow clip source.
extra_clips.push(shadow_clip_source);
// Outset shadows are expanded by the shadow
// region from the original primitive.
LayoutPrimitiveInfo::with_clip_rect(dest_rect, prim_info.clip_rect)
}
BoxShadowClipMode::Inset => {
// If the inner shadow rect contains the prim
// rect, no pixels will be shadowed.
if border_radius.is_zero() && shadow_rect
.inflate(-blur_radius, -blur_radius)
.contains_box(&prim_info.rect)
{
return;
}
// Inset shadows are still visible, even if the
// inset shadow rect becomes invalid (they will
// just look like a solid rectangle).
if !shadow_rect.is_empty() {
extra_clips.push(shadow_clip_source);
}
// Inset shadows draw inside the original primitive.
prim_info.clone()
}
};
self.add_primitive(
spatial_node_index,
clip_node_id,
&prim_info,
extra_clips,
prim,
);
}
}
}
fn adjust_border_radius_for_box_shadow(radius: BorderRadius, spread_amount: f32) -> BorderRadius {
BorderRadius {
top_left: adjust_corner_for_box_shadow(radius.top_left, spread_amount),
top_right: adjust_corner_for_box_shadow(radius.top_right, spread_amount),
bottom_right: adjust_corner_for_box_shadow(radius.bottom_right, spread_amount),
bottom_left: adjust_corner_for_box_shadow(radius.bottom_left, spread_amount),
}
}
fn adjust_corner_for_box_shadow(corner: LayoutSize, spread_amount: f32) -> LayoutSize {
LayoutSize::new(
adjust_radius_for_box_shadow(corner.width, spread_amount),
adjust_radius_for_box_shadow(corner.height, spread_amount),
)
}
fn adjust_radius_for_box_shadow(border_radius: f32, spread_amount: f32) -> f32 {
if border_radius > 0.0 {
(border_radius + spread_amount).max(0.0)
} else {
0.0
}
}