Anforderungen  |   Konzepte  |   Entwurf  |   Entwicklung  |   Qualitätssicherung  |   Lebenszyklus  |   Steuerung
 
 
 
 


Impressum render_task.rs   Sprache: unbekannt

 
/* 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
 * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

use api::{CompositeOperator, FilterPrimitive, FilterPrimitiveInput, FilterPrimitiveKind, SVGFE_GRAPH_MAX};
use api::{LineStyle, LineOrientation, ClipMode, MixBlendMode, ColorF, ColorSpace, FilterOpGraphPictureBufferId};
use api::MAX_RENDER_TASK_SIZE;
use api::units::*;
use crate::box_shadow::BLUR_SAMPLE_SCALE;
use crate::clip::{ClipDataStore, ClipItemKind, ClipStore, ClipNodeRange};
use crate::command_buffer::{CommandBufferIndex, QuadFlags};
use crate::pattern::{PatternKind, PatternShaderInput};
use crate::spatial_tree::SpatialNodeIndex;
use crate::filterdata::SFilterData;
use crate::frame_builder::FrameBuilderConfig;
use crate::gpu_cache::{GpuCache, GpuCacheAddress, GpuCacheHandle};
use crate::gpu_types::{BorderInstance, ImageSource, UvRectKind, TransformPaletteId};
use crate::internal_types::{CacheTextureId, FastHashMap, FilterGraphNode, FilterGraphOp, FilterGraphPictureReference, SVGFE_CONVOLVE_VALUES_LIMIT, TextureSource, Swizzle};
use crate::picture::{ResolvedSurfaceTexture, MAX_SURFACE_SIZE};
use crate::prim_store::ClipData;
use crate::prim_store::gradient::{
    FastLinearGradientTask, RadialGradientTask,
    ConicGradientTask, LinearGradientTask,
};
use crate::resource_cache::{ResourceCache, ImageRequest};
use std::{usize, f32, i32, u32};
use crate::renderer::{GpuBufferAddress, GpuBufferBuilderF};
use crate::render_backend::DataStores;
use crate::render_target::{ResolveOp, RenderTargetKind};
use crate::render_task_graph::{PassId, RenderTaskId, RenderTaskGraphBuilder};
use crate::render_task_cache::{RenderTaskCacheEntryHandle, RenderTaskCacheKey, RenderTaskCacheKeyKind, RenderTaskParent};
use crate::segment::EdgeAaSegmentMask;
use crate::surface::SurfaceBuilder;
use smallvec::SmallVec;

const FLOATS_PER_RENDER_TASK_INFO: usize = 8;
pub const MAX_BLUR_STD_DEVIATION: f32 = 4.0;
pub const MIN_DOWNSCALING_RT_SIZE: i32 = 8;

fn render_task_sanity_check(size: &DeviceIntSize) {
    if size.width > MAX_RENDER_TASK_SIZE ||
        size.height > MAX_RENDER_TASK_SIZE {
        error!("Attempting to create a render task of size {}x{}", size.width, size.height);
        panic!();
    }
}

#[derive(Debug, Copy, Clone, PartialEq)]
#[repr(C)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct RenderTaskAddress(pub i32);

impl Into<RenderTaskAddress> for RenderTaskId {
    fn into(self) -> RenderTaskAddress {
        RenderTaskAddress(self.index as i32)
    }
}

/// A render task location that targets a persistent output buffer which
/// will be retained over multiple frames.
#[derive(Clone, Debug, Eq, PartialEq, Hash)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub enum StaticRenderTaskSurface {
    /// The output of the `RenderTask` will be persisted beyond this frame, and
    /// thus should be drawn into the `TextureCache`.
    TextureCache {
        /// Which texture in the texture cache should be drawn into.
        texture: CacheTextureId,
        /// What format this texture cache surface is
        target_kind: RenderTargetKind,
    },
    /// Only used as a source for render tasks, can be any texture including an
    /// external one.
    ReadOnly {
        source: TextureSource,
    },
    /// This render task will be drawn to a picture cache texture that is
    /// persisted between both frames and scenes, if the content remains valid.
    PictureCache {
        /// Describes either a WR texture or a native OS compositor target
        surface: ResolvedSurfaceTexture,
    },
}

/// Identifies the output buffer location for a given `RenderTask`.
#[derive(Clone, Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub enum RenderTaskLocation {
    // Towards the beginning of the frame, most task locations are typically not
    // known yet, in which case they are set to one of the following variants:

    /// A dynamic task that has not yet been allocated a texture and rect.
    Unallocated {
        /// Requested size of this render task
        size: DeviceIntSize,
    },
    /// Will be replaced by a Static location after the texture cache update.
    CacheRequest {
        size: DeviceIntSize,
    },
    /// Same allocation as an existing task deeper in the dependency graph
    Existing {
        parent_task_id: RenderTaskId,
        /// Requested size of this render task
        size: DeviceIntSize,
    },

    // Before batching begins, we expect that locations have been resolved to
    // one of the following variants:

    /// The `RenderTask` should be drawn to a target provided by the atlas
    /// allocator. This is the most common case.
    Dynamic {
        /// Texture that this task was allocated to render on
        texture_id: CacheTextureId,
        /// Rectangle in the texture this task occupies
        rect: DeviceIntRect,
    },
    /// A task that is output to a persistent / retained target.
    Static {
        /// Target to draw to
        surface: StaticRenderTaskSurface,
        /// Rectangle in the texture this task occupies
        rect: DeviceIntRect,
    },
}

impl RenderTaskLocation {
    /// Returns true if this is a dynamic location.
    pub fn is_dynamic(&self) -> bool {
        match *self {
            RenderTaskLocation::Dynamic { .. } => true,
            _ => false,
        }
    }

    pub fn size(&self) -> DeviceIntSize {
        match self {
            RenderTaskLocation::Unallocated { size } => *size,
            RenderTaskLocation::Dynamic { rect, .. } => rect.size(),
            RenderTaskLocation::Static { rect, .. } => rect.size(),
            RenderTaskLocation::CacheRequest { size } => *size,
            RenderTaskLocation::Existing { size, .. } => *size,
        }
    }
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct CachedTask {
    pub target_kind: RenderTargetKind,
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct CacheMaskTask {
    pub actual_rect: DeviceRect,
    pub root_spatial_node_index: SpatialNodeIndex,
    pub clip_node_range: ClipNodeRange,
    pub device_pixel_scale: DevicePixelScale,
    pub clear_to_one: bool,
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct ClipRegionTask {
    pub local_pos: LayoutPoint,
    pub device_pixel_scale: DevicePixelScale,
    pub clip_data: ClipData,
    pub clear_to_one: bool,
}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct EmptyTask {
    pub content_origin: DevicePoint,
    pub device_pixel_scale: DevicePixelScale,
    pub raster_spatial_node_index: SpatialNodeIndex,
}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct PrimTask {
    pub pattern: PatternKind,
    pub pattern_input: PatternShaderInput,
    pub device_pixel_scale: DevicePixelScale,
    pub content_origin: DevicePoint,
    pub prim_address_f: GpuBufferAddress,
    pub raster_spatial_node_index: SpatialNodeIndex,
    pub transform_id: TransformPaletteId,
    pub edge_flags: EdgeAaSegmentMask,
    pub quad_flags: QuadFlags,
    pub prim_needs_scissor_rect: bool,
    pub texture_input: RenderTaskId,
}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct TileCompositeTask {
    pub clear_color: ColorF,
    pub scissor_rect: DeviceIntRect,
    pub valid_rect: DeviceIntRect,
    pub task_id: Option<RenderTaskId>,
    pub sub_rect_offset: DeviceIntVector2D,
}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct PictureTask {
    pub can_merge: bool,
    pub content_origin: DevicePoint,
    pub surface_spatial_node_index: SpatialNodeIndex,
    pub raster_spatial_node_index: SpatialNodeIndex,
    pub device_pixel_scale: DevicePixelScale,
    pub clear_color: Option<ColorF>,
    pub scissor_rect: Option<DeviceIntRect>,
    pub valid_rect: Option<DeviceIntRect>,
    pub cmd_buffer_index: CommandBufferIndex,
    pub resolve_op: Option<ResolveOp>,

    pub can_use_shared_surface: bool,
}

impl PictureTask {
    /// Copy an existing picture task, but set a new command buffer for it to build in to.
    /// Used for pictures that are split between render tasks (e.g. pre/post a backdrop
    /// filter). Subsequent picture tasks never have a clear color as they are by definition
    /// going to write to an existing target
    pub fn duplicate(
        &self,
        cmd_buffer_index: CommandBufferIndex,
    ) -> Self {
        assert_eq!(self.resolve_op, None);

        PictureTask {
            clear_color: None,
            cmd_buffer_index,
            resolve_op: None,
            can_use_shared_surface: false,
            ..*self
        }
    }
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct BlurTask {
    pub blur_std_deviation: f32,
    pub target_kind: RenderTargetKind,
    pub blur_region: DeviceIntSize,
}

impl BlurTask {
    // In order to do the blur down-scaling passes without introducing errors, we need the
    // source of each down-scale pass to be a multuple of two. If need be, this inflates
    // the source size so that each down-scale pass will sample correctly.
    pub fn adjusted_blur_source_size(original_size: DeviceSize, mut std_dev: DeviceSize) -> DeviceIntSize {
        let mut adjusted_size = original_size;
        let mut scale_factor = 1.0;
        while std_dev.width > MAX_BLUR_STD_DEVIATION && std_dev.height > MAX_BLUR_STD_DEVIATION {
            if adjusted_size.width < MIN_DOWNSCALING_RT_SIZE as f32 ||
               adjusted_size.height < MIN_DOWNSCALING_RT_SIZE as f32 {
                break;
            }
            std_dev = std_dev * 0.5;
            scale_factor *= 2.0;
            adjusted_size = (original_size.to_f32() / scale_factor).ceil();
        }

        (adjusted_size * scale_factor).round().to_i32()
    }
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct ScalingTask {
    pub target_kind: RenderTargetKind,
    pub padding: DeviceIntSideOffsets,
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct BorderTask {
    pub instances: Vec<BorderInstance>,
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct BlitTask {
    pub source: RenderTaskId,
    // Normalized rect within the source task to blit from
    pub source_rect: DeviceIntRect,
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct LineDecorationTask {
    pub wavy_line_thickness: f32,
    pub style: LineStyle,
    pub orientation: LineOrientation,
    pub local_size: LayoutSize,
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub enum SvgFilterInfo {
    Blend(MixBlendMode),
    Flood(ColorF),
    LinearToSrgb,
    SrgbToLinear,
    Opacity(f32),
    ColorMatrix(Box<[f32; 20]>),
    DropShadow(ColorF),
    Offset(DeviceVector2D),
    ComponentTransfer(SFilterData),
    Composite(CompositeOperator),
    // TODO: This is used as a hack to ensure that a blur task's input is always in the blur's previous pass.
    Identity,
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct SvgFilterTask {
    pub info: SvgFilterInfo,
    pub extra_gpu_cache_handle: Option<GpuCacheHandle>,
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct SVGFEFilterTask {
    pub node: FilterGraphNode,
    pub op: FilterGraphOp,
    pub content_origin: DevicePoint,
    pub extra_gpu_cache_handle: Option<GpuCacheHandle>,
}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct ReadbackTask {
    // The offset of the rect that needs to be read back, in the
    // device space of the surface that will be read back from.
    // If this is None, there is no readback surface available
    // and this is a dummy (empty) readback.
    pub readback_origin: Option<DevicePoint>,
}

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct RenderTaskData {
    pub data: [f32; FLOATS_PER_RENDER_TASK_INFO],
}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub enum RenderTaskKind {
    Image(ImageRequest),
    Cached(CachedTask),
    Picture(PictureTask),
    CacheMask(CacheMaskTask),
    ClipRegion(ClipRegionTask),
    VerticalBlur(BlurTask),
    HorizontalBlur(BlurTask),
    Readback(ReadbackTask),
    Scaling(ScalingTask),
    Blit(BlitTask),
    Border(BorderTask),
    LineDecoration(LineDecorationTask),
    FastLinearGradient(FastLinearGradientTask),
    LinearGradient(LinearGradientTask),
    RadialGradient(RadialGradientTask),
    ConicGradient(ConicGradientTask),
    SvgFilter(SvgFilterTask),
    SVGFENode(SVGFEFilterTask),
    TileComposite(TileCompositeTask),
    Prim(PrimTask),
    Empty(EmptyTask),
    #[cfg(test)]
    Test(RenderTargetKind),
}

impl RenderTaskKind {
    pub fn is_a_rendering_operation(&self) -> bool {
        match self {
            &RenderTaskKind::Image(..) => false,
            &RenderTaskKind::Cached(..) => false,
            _ => true,
        }
    }

    /// Whether this task can be allocated on a shared render target surface
    pub fn can_use_shared_surface(&self) -> bool {
        match self {
            &RenderTaskKind::Picture(ref info) => info.can_use_shared_surface,
            _ => true,
        }
    }

    pub fn should_advance_pass(&self) -> bool {
        match self {
            &RenderTaskKind::Image(..) => false,
            &RenderTaskKind::Cached(..) => false,
            _ => true,
        }
    }

    pub fn as_str(&self) -> &'static str {
        match *self {
            RenderTaskKind::Image(..) => "Image",
            RenderTaskKind::Cached(..) => "Cached",
            RenderTaskKind::Picture(..) => "Picture",
            RenderTaskKind::CacheMask(..) => "CacheMask",
            RenderTaskKind::ClipRegion(..) => "ClipRegion",
            RenderTaskKind::VerticalBlur(..) => "VerticalBlur",
            RenderTaskKind::HorizontalBlur(..) => "HorizontalBlur",
            RenderTaskKind::Readback(..) => "Readback",
            RenderTaskKind::Scaling(..) => "Scaling",
            RenderTaskKind::Blit(..) => "Blit",
            RenderTaskKind::Border(..) => "Border",
            RenderTaskKind::LineDecoration(..) => "LineDecoration",
            RenderTaskKind::FastLinearGradient(..) => "FastLinearGradient",
            RenderTaskKind::LinearGradient(..) => "LinearGradient",
            RenderTaskKind::RadialGradient(..) => "RadialGradient",
            RenderTaskKind::ConicGradient(..) => "ConicGradient",
            RenderTaskKind::SvgFilter(..) => "SvgFilter",
            RenderTaskKind::SVGFENode(..) => "SVGFENode",
            RenderTaskKind::TileComposite(..) => "TileComposite",
            RenderTaskKind::Prim(..) => "Prim",
            RenderTaskKind::Empty(..) => "Empty",
            #[cfg(test)]
            RenderTaskKind::Test(..) => "Test",
        }
    }

    pub fn target_kind(&self) -> RenderTargetKind {
        match *self {
            RenderTaskKind::Image(..) |
            RenderTaskKind::LineDecoration(..) |
            RenderTaskKind::Readback(..) |
            RenderTaskKind::Border(..) |
            RenderTaskKind::FastLinearGradient(..) |
            RenderTaskKind::LinearGradient(..) |
            RenderTaskKind::RadialGradient(..) |
            RenderTaskKind::ConicGradient(..) |
            RenderTaskKind::Picture(..) |
            RenderTaskKind::Blit(..) |
            RenderTaskKind::TileComposite(..) |
            RenderTaskKind::Prim(..) |
            RenderTaskKind::SvgFilter(..) => {
                RenderTargetKind::Color
            }
            RenderTaskKind::SVGFENode(..) => {
                RenderTargetKind::Color
            }

            RenderTaskKind::ClipRegion(..) |
            RenderTaskKind::CacheMask(..) |
            RenderTaskKind::Empty(..) => {
                RenderTargetKind::Alpha
            }

            RenderTaskKind::VerticalBlur(ref task_info) |
            RenderTaskKind::HorizontalBlur(ref task_info) => {
                task_info.target_kind
            }

            RenderTaskKind::Scaling(ref task_info) => {
                task_info.target_kind
            }

            RenderTaskKind::Cached(ref task_info) => {
                task_info.target_kind
            }

            #[cfg(test)]
            RenderTaskKind::Test(kind) => kind,
        }
    }

    pub fn new_tile_composite(
        sub_rect_offset: DeviceIntVector2D,
        scissor_rect: DeviceIntRect,
        valid_rect: DeviceIntRect,
        clear_color: ColorF,
    ) -> Self {
        RenderTaskKind::TileComposite(TileCompositeTask {
            task_id: None,
            sub_rect_offset,
            scissor_rect,
            valid_rect,
            clear_color,
        })
    }

    pub fn new_picture(
        size: DeviceIntSize,
        needs_scissor_rect: bool,
        content_origin: DevicePoint,
        surface_spatial_node_index: SpatialNodeIndex,
        raster_spatial_node_index: SpatialNodeIndex,
        device_pixel_scale: DevicePixelScale,
        scissor_rect: Option<DeviceIntRect>,
        valid_rect: Option<DeviceIntRect>,
        clear_color: Option<ColorF>,
        cmd_buffer_index: CommandBufferIndex,
        can_use_shared_surface: bool,
    ) -> Self {
        render_task_sanity_check(&size);

        RenderTaskKind::Picture(PictureTask {
            content_origin,
            can_merge: !needs_scissor_rect,
            surface_spatial_node_index,
            raster_spatial_node_index,
            device_pixel_scale,
            scissor_rect,
            valid_rect,
            clear_color,
            cmd_buffer_index,
            resolve_op: None,
            can_use_shared_surface,
        })
    }

    pub fn new_prim(
        pattern: PatternKind,
        pattern_input: PatternShaderInput,
        raster_spatial_node_index: SpatialNodeIndex,
        device_pixel_scale: DevicePixelScale,
        content_origin: DevicePoint,
        prim_address_f: GpuBufferAddress,
        transform_id: TransformPaletteId,
        edge_flags: EdgeAaSegmentMask,
        quad_flags: QuadFlags,
        prim_needs_scissor_rect: bool,
        texture_input: RenderTaskId,
    ) -> Self {
        RenderTaskKind::Prim(PrimTask {
            pattern,
            pattern_input,
            raster_spatial_node_index,
            device_pixel_scale,
            content_origin,
            prim_address_f,
            transform_id,
            edge_flags,
            quad_flags,
            prim_needs_scissor_rect,
            texture_input,
        })
    }

    pub fn new_readback(
        readback_origin: Option<DevicePoint>,
    ) -> Self {
        RenderTaskKind::Readback(
            ReadbackTask {
                readback_origin,
            }
        )
    }

    pub fn new_line_decoration(
        style: LineStyle,
        orientation: LineOrientation,
        wavy_line_thickness: f32,
        local_size: LayoutSize,
    ) -> Self {
        RenderTaskKind::LineDecoration(LineDecorationTask {
            style,
            orientation,
            wavy_line_thickness,
            local_size,
        })
    }

    pub fn new_border_segment(
        instances: Vec<BorderInstance>,
    ) -> Self {
        RenderTaskKind::Border(BorderTask {
            instances,
        })
    }

    pub fn new_rounded_rect_mask(
        local_pos: LayoutPoint,
        clip_data: ClipData,
        device_pixel_scale: DevicePixelScale,
        fb_config: &FrameBuilderConfig,
    ) -> Self {
        RenderTaskKind::ClipRegion(ClipRegionTask {
            local_pos,
            device_pixel_scale,
            clip_data,
            clear_to_one: fb_config.gpu_supports_fast_clears,
        })
    }

    pub fn new_mask(
        outer_rect: DeviceIntRect,
        clip_node_range: ClipNodeRange,
        root_spatial_node_index: SpatialNodeIndex,
        clip_store: &mut ClipStore,
        gpu_cache: &mut GpuCache,
        gpu_buffer_builder: &mut GpuBufferBuilderF,
        resource_cache: &mut ResourceCache,
        rg_builder: &mut RenderTaskGraphBuilder,
        clip_data_store: &mut ClipDataStore,
        device_pixel_scale: DevicePixelScale,
        fb_config: &FrameBuilderConfig,
        surface_builder: &mut SurfaceBuilder,
    ) -> RenderTaskId {
        // Step through the clip sources that make up this mask. If we find
        // any box-shadow clip sources, request that image from the render
        // task cache. This allows the blurred box-shadow rect to be cached
        // in the texture cache across frames.
        // TODO(gw): Consider moving this logic outside this function, especially
        //           as we add more clip sources that depend on render tasks.
        // TODO(gw): If this ever shows up in a profile, we could pre-calculate
        //           whether a ClipSources contains any box-shadows and skip
        //           this iteration for the majority of cases.
        let task_size = outer_rect.size();

        // If we have a potentially tiled clip mask, clear the mask area first. Otherwise,
        // the first (primary) clip mask will overwrite all the clip mask pixels with
        // blending disabled to set to the initial value.

        let clip_task_id = rg_builder.add().init(
            RenderTask::new_dynamic(
                task_size,
                RenderTaskKind::CacheMask(CacheMaskTask {
                    actual_rect: outer_rect.to_f32(),
                    clip_node_range,
                    root_spatial_node_index,
                    device_pixel_scale,
                    clear_to_one: fb_config.gpu_supports_fast_clears,
                }),
            )
        );

        for i in 0 .. clip_node_range.count {
            let clip_instance = clip_store.get_instance_from_range(&clip_node_range, i);
            let clip_node = &mut clip_data_store[clip_instance.handle];
            match clip_node.item.kind {
                ClipItemKind::BoxShadow { ref mut source } => {
                    let (cache_size, cache_key) = source.cache_key
                        .as_ref()
                        .expect("bug: no cache key set")
                        .clone();
                    let blur_radius_dp = cache_key.blur_radius_dp as f32;
                    let device_pixel_scale = DevicePixelScale::new(cache_key.device_pixel_scale.to_f32_px());

                    // Request a cacheable render task with a blurred, minimal
                    // sized box-shadow rect.
                    source.render_task = Some(resource_cache.request_render_task(
                        Some(RenderTaskCacheKey {
                            size: cache_size,
                            kind: RenderTaskCacheKeyKind::BoxShadow(cache_key),
                        }),
                        false,
                        RenderTaskParent::RenderTask(clip_task_id),
                        gpu_cache,
                        gpu_buffer_builder,
                        rg_builder,
                        surface_builder,
                        &mut |rg_builder, _, _| {
                            let clip_data = ClipData::rounded_rect(
                                source.minimal_shadow_rect.size(),
                                &source.shadow_radius,
                                ClipMode::Clip,
                            );

                            // Draw the rounded rect.
                            let mask_task_id = rg_builder.add().init(RenderTask::new_dynamic(
                                cache_size,
                                RenderTaskKind::new_rounded_rect_mask(
                                    source.minimal_shadow_rect.min,
                                    clip_data,
                                    device_pixel_scale,
                                    fb_config,
                                ),
                            ));

                            // Blur it
                            RenderTask::new_blur(
                                DeviceSize::new(blur_radius_dp, blur_radius_dp),
                                mask_task_id,
                                rg_builder,
                                RenderTargetKind::Alpha,
                                None,
                                cache_size,
                            )
                        }
                    ));
                }
                ClipItemKind::Rectangle { .. } |
                ClipItemKind::RoundedRectangle { .. } |
                ClipItemKind::Image { .. } => {}
            }
        }

        clip_task_id
    }

    // Write (up to) 8 floats of data specific to the type
    // of render task that is provided to the GPU shaders
    // via a vertex texture.
    pub fn write_task_data(
        &self,
        target_rect: DeviceIntRect,
    ) -> RenderTaskData {
        // NOTE: The ordering and layout of these structures are
        //       required to match both the GPU structures declared
        //       in prim_shared.glsl, and also the uses in submit_batch()
        //       in renderer.rs.
        // TODO(gw): Maybe there's a way to make this stuff a bit
        //           more type-safe. Although, it will always need
        //           to be kept in sync with the GLSL code anyway.

        let data = match self {
            RenderTaskKind::Picture(ref task) => {
                // Note: has to match `PICTURE_TYPE_*` in shaders
                [
                    task.device_pixel_scale.0,
                    task.content_origin.x,
                    task.content_origin.y,
                    0.0,
                ]
            }
            RenderTaskKind::Prim(ref task) => {
                [
                    // NOTE: This must match the render task data format for Picture tasks currently
                    task.device_pixel_scale.0,
                    task.content_origin.x,
                    task.content_origin.y,
                    0.0,
                ]
            }
            RenderTaskKind::Empty(ref task) => {
                [
                    // NOTE: This must match the render task data format for Picture tasks currently
                    task.device_pixel_scale.0,
                    task.content_origin.x,
                    task.content_origin.y,
                    0.0,
                ]
            }
            RenderTaskKind::CacheMask(ref task) => {
                [
                    task.device_pixel_scale.0,
                    task.actual_rect.min.x,
                    task.actual_rect.min.y,
                    0.0,
                ]
            }
            RenderTaskKind::ClipRegion(ref task) => {
                [
                    task.device_pixel_scale.0,
                    0.0,
                    0.0,
                    0.0,
                ]
            }
            RenderTaskKind::VerticalBlur(_) |
            RenderTaskKind::HorizontalBlur(_) => {
                // TODO(gw): Make this match Picture tasks so that we can draw
                //           sub-passes on them to apply box-shadow masks.
                [
                    0.0,
                    0.0,
                    0.0,
                    0.0,
                ]
            }
            RenderTaskKind::Image(..) |
            RenderTaskKind::Cached(..) |
            RenderTaskKind::Readback(..) |
            RenderTaskKind::Scaling(..) |
            RenderTaskKind::Border(..) |
            RenderTaskKind::LineDecoration(..) |
            RenderTaskKind::FastLinearGradient(..) |
            RenderTaskKind::LinearGradient(..) |
            RenderTaskKind::RadialGradient(..) |
            RenderTaskKind::ConicGradient(..) |
            RenderTaskKind::TileComposite(..) |
            RenderTaskKind::Blit(..) => {
                [0.0; 4]
            }

            RenderTaskKind::SvgFilter(ref task) => {
                match task.info {
                    SvgFilterInfo::Opacity(opacity) => [opacity, 0.0, 0.0, 0.0],
                    SvgFilterInfo::Offset(offset) => [offset.x, offset.y, 0.0, 0.0],
                    _ => [0.0; 4]
                }
            }
            RenderTaskKind::SVGFENode(_task) => {
                // we don't currently use this for SVGFE filters.
                // see SVGFEFilterInstance instead
                [0.0; 4]
            }

            #[cfg(test)]
            RenderTaskKind::Test(..) => {
                [0.0; 4]
            }
        };

        RenderTaskData {
            data: [
                target_rect.min.x as f32,
                target_rect.min.y as f32,
                target_rect.max.x as f32,
                target_rect.max.y as f32,
                data[0],
                data[1],
                data[2],
                data[3],
            ]
        }
    }

    pub fn write_gpu_blocks(
        &mut self,
        gpu_cache: &mut GpuCache,
    ) {
        match self {
            RenderTaskKind::SvgFilter(ref mut filter_task) => {
                match filter_task.info {
                    SvgFilterInfo::ColorMatrix(ref matrix) => {
                        let handle = filter_task.extra_gpu_cache_handle.get_or_insert_with(GpuCacheHandle::new);
                        if let Some(mut request) = gpu_cache.request(handle) {
                            for i in 0..5 {
                                request.push([matrix[i*4], matrix[i*4+1], matrix[i*4+2], matrix[i*4+3]]);
                            }
                        }
                    }
                    SvgFilterInfo::DropShadow(color) |
                    SvgFilterInfo::Flood(color) => {
                        let handle = filter_task.extra_gpu_cache_handle.get_or_insert_with(GpuCacheHandle::new);
                        if let Some(mut request) = gpu_cache.request(handle) {
                            request.push(color.to_array());
                        }
                    }
                    SvgFilterInfo::ComponentTransfer(ref data) => {
                        let handle = filter_task.extra_gpu_cache_handle.get_or_insert_with(GpuCacheHandle::new);
                        if let Some(request) = gpu_cache.request(handle) {
                            data.update(request);
                        }
                    }
                    SvgFilterInfo::Composite(ref operator) => {
                        if let CompositeOperator::Arithmetic(k_vals) = operator {
                            let handle = filter_task.extra_gpu_cache_handle.get_or_insert_with(GpuCacheHandle::new);
                            if let Some(mut request) = gpu_cache.request(handle) {
                                request.push(*k_vals);
                            }
                        }
                    }
                    _ => {},
                }
            }
            RenderTaskKind::SVGFENode(ref mut filter_task) => {
                match filter_task.op {
                    FilterGraphOp::SVGFEBlendDarken => {}
                    FilterGraphOp::SVGFEBlendLighten => {}
                    FilterGraphOp::SVGFEBlendMultiply => {}
                    FilterGraphOp::SVGFEBlendNormal => {}
                    FilterGraphOp::SVGFEBlendScreen => {}
                    FilterGraphOp::SVGFEBlendOverlay => {}
                    FilterGraphOp::SVGFEBlendColorDodge => {}
                    FilterGraphOp::SVGFEBlendColorBurn => {}
                    FilterGraphOp::SVGFEBlendHardLight => {}
                    FilterGraphOp::SVGFEBlendSoftLight => {}
                    FilterGraphOp::SVGFEBlendDifference => {}
                    FilterGraphOp::SVGFEBlendExclusion => {}
                    FilterGraphOp::SVGFEBlendHue => {}
                    FilterGraphOp::SVGFEBlendSaturation => {}
                    FilterGraphOp::SVGFEBlendColor => {}
                    FilterGraphOp::SVGFEBlendLuminosity => {}
                    FilterGraphOp::SVGFEColorMatrix{values: matrix} => {
                        let handle = filter_task.extra_gpu_cache_handle.get_or_insert_with(GpuCacheHandle::new);
                        if let Some(mut request) = gpu_cache.request(handle) {
                            for i in 0..5 {
                                request.push([matrix[i*4], matrix[i*4+1], matrix[i*4+2], matrix[i*4+3]]);
                            }
                        }
                    }
                    FilterGraphOp::SVGFEComponentTransfer => unreachable!(),
                    FilterGraphOp::SVGFEComponentTransferInterned{..} => {}
                    FilterGraphOp::SVGFECompositeArithmetic{k1, k2, k3, k4} => {
                        let handle = filter_task.extra_gpu_cache_handle.get_or_insert_with(GpuCacheHandle::new);
                        if let Some(mut request) = gpu_cache.request(handle) {
                            request.push([k1, k2, k3, k4]);
                        }
                    }
                    FilterGraphOp::SVGFECompositeATop => {}
                    FilterGraphOp::SVGFECompositeIn => {}
                    FilterGraphOp::SVGFECompositeLighter => {}
                    FilterGraphOp::SVGFECompositeOut => {}
                    FilterGraphOp::SVGFECompositeOver => {}
                    FilterGraphOp::SVGFECompositeXOR => {}
                    FilterGraphOp::SVGFEConvolveMatrixEdgeModeDuplicate{order_x, order_y, kernel, divisor, bias, target_x, target_y, kernel_unit_length_x, kernel_unit_length_y, preserve_alpha} |
                    FilterGraphOp::SVGFEConvolveMatrixEdgeModeNone{order_x, order_y, kernel, divisor, bias, target_x, target_y, kernel_unit_length_x, kernel_unit_length_y, preserve_alpha} |
                    FilterGraphOp::SVGFEConvolveMatrixEdgeModeWrap{order_x, order_y, kernel, divisor, bias, target_x, target_y, kernel_unit_length_x, kernel_unit_length_y, preserve_alpha} => {
                        let handle = filter_task.extra_gpu_cache_handle.get_or_insert_with(GpuCacheHandle::new);
                        if let Some(mut request) = gpu_cache.request(handle) {
                            request.push([-target_x as f32, -target_y as f32, order_x as f32, order_y as f32]);
                            request.push([kernel_unit_length_x as f32, kernel_unit_length_y as f32, 1.0 / divisor, bias]);
                            assert!(SVGFE_CONVOLVE_VALUES_LIMIT == 25);
                            request.push([kernel[0], kernel[1], kernel[2], kernel[3]]);
                            request.push([kernel[4], kernel[5], kernel[6], kernel[7]]);
                            request.push([kernel[8], kernel[9], kernel[10], kernel[11]]);
                            request.push([kernel[12], kernel[13], kernel[14], kernel[15]]);
                            request.push([kernel[16], kernel[17], kernel[18], kernel[19]]);
                            request.push([kernel[20], 0.0, 0.0, preserve_alpha as f32]);
                        }
                    }
                    FilterGraphOp::SVGFEDiffuseLightingDistant{..} => {}
                    FilterGraphOp::SVGFEDiffuseLightingPoint{..} => {}
                    FilterGraphOp::SVGFEDiffuseLightingSpot{..} => {}
                    FilterGraphOp::SVGFEDisplacementMap{scale, x_channel_selector, y_channel_selector} => {
                        let handle = filter_task.extra_gpu_cache_handle.get_or_insert_with(GpuCacheHandle::new);
                        if let Some(mut request) = gpu_cache.request(handle) {
                            request.push([x_channel_selector as f32, y_channel_selector as f32, scale, 0.0]);
                        }
                    }
                    FilterGraphOp::SVGFEDropShadow{color, ..} |
                    FilterGraphOp::SVGFEFlood{color} => {
                        let handle = filter_task.extra_gpu_cache_handle.get_or_insert_with(GpuCacheHandle::new);
                        if let Some(mut request) = gpu_cache.request(handle) {
                            request.push(color.to_array());
                        }
                    }
                    FilterGraphOp::SVGFEGaussianBlur{..} => {}
                    FilterGraphOp::SVGFEIdentity => {}
                    FilterGraphOp::SVGFEImage{..} => {}
                    FilterGraphOp::SVGFEMorphologyDilate{radius_x, radius_y} |
                    FilterGraphOp::SVGFEMorphologyErode{radius_x, radius_y} => {
                        let handle = filter_task.extra_gpu_cache_handle.get_or_insert_with(GpuCacheHandle::new);
                        if let Some(mut request) = gpu_cache.request(handle) {
                            request.push([radius_x, radius_y, 0.0, 0.0]);
                        }
                    }
                    FilterGraphOp::SVGFEOpacity{..} => {}
                    FilterGraphOp::SVGFESourceAlpha => {}
                    FilterGraphOp::SVGFESourceGraphic => {}
                    FilterGraphOp::SVGFESpecularLightingDistant{..} => {}
                    FilterGraphOp::SVGFESpecularLightingPoint{..} => {}
                    FilterGraphOp::SVGFESpecularLightingSpot{..} => {}
                    FilterGraphOp::SVGFETile => {}
                    FilterGraphOp::SVGFEToAlpha{..} => {}
                    FilterGraphOp::SVGFETurbulenceWithFractalNoiseWithNoStitching{..} => {}
                    FilterGraphOp::SVGFETurbulenceWithFractalNoiseWithStitching{..} => {}
                    FilterGraphOp::SVGFETurbulenceWithTurbulenceNoiseWithNoStitching{..} => {}
                    FilterGraphOp::SVGFETurbulenceWithTurbulenceNoiseWithStitching{..} => {}
                }
            }
            _ => {}
        }
    }
}

/// In order to avoid duplicating the down-scaling and blur passes when a picture has several blurs,
/// we use a local (primitive-level) cache of the render tasks generated for a single shadowed primitive
/// in a single frame.
pub type BlurTaskCache = FastHashMap<BlurTaskKey, RenderTaskId>;

/// Since we only use it within a single primitive, the key only needs to contain the down-scaling level
/// and the blur std deviation.
#[derive(Copy, Clone, Debug, PartialEq, Eq, Hash)]
pub enum BlurTaskKey {
    DownScale(u32),
    Blur { downscale_level: u32, stddev_x: u32, stddev_y: u32 },
}

impl BlurTaskKey {
    fn downscale_and_blur(downscale_level: u32, blur_stddev: DeviceSize) -> Self {
        // Quantise the std deviations and store it as integers to work around
        // Eq and Hash's f32 allergy.
        // The blur radius is rounded before RenderTask::new_blur so we don't need
        // a lot of precision.
        const QUANTIZATION_FACTOR: f32 = 1024.0;
        let stddev_x = (blur_stddev.width * QUANTIZATION_FACTOR) as u32;
        let stddev_y = (blur_stddev.height * QUANTIZATION_FACTOR) as u32;
        BlurTaskKey::Blur { downscale_level, stddev_x, stddev_y }
    }
}

// The majority of render tasks have 0, 1 or 2 dependencies, except for pictures that
// typically have dozens to hundreds of dependencies. SmallVec with 2 inline elements
// avoids many tiny heap allocations in pages with a lot of text shadows and other
// types of render tasks.
pub type TaskDependencies = SmallVec<[RenderTaskId;2]>;

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct MaskSubPass {
    pub clip_node_range: ClipNodeRange,
    pub prim_spatial_node_index: SpatialNodeIndex,
    pub prim_address_f: GpuBufferAddress,
}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub enum SubPass {
    Masks {
        masks: MaskSubPass,
    },
}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct RenderTask {
    pub location: RenderTaskLocation,
    pub children: TaskDependencies,
    pub kind: RenderTaskKind,
    pub sub_pass: Option<SubPass>,

    // TODO(gw): These fields and perhaps others can become private once the
    //           frame_graph / render_task source files are unified / cleaned up.
    pub free_after: PassId,
    pub render_on: PassId,

    /// The gpu cache handle for the render task's destination rect.
    ///
    /// Will be set to None if the render task is cached, in which case the texture cache
    /// manages the handle.
    pub uv_rect_handle: GpuCacheHandle,
    pub cache_handle: Option<RenderTaskCacheEntryHandle>,
    uv_rect_kind: UvRectKind,
}

impl RenderTask {
    pub fn new(
        location: RenderTaskLocation,
        kind: RenderTaskKind,
    ) -> Self {
        render_task_sanity_check(&location.size());

        RenderTask {
            location,
            children: TaskDependencies::new(),
            kind,
            free_after: PassId::MAX,
            render_on: PassId::MIN,
            uv_rect_handle: GpuCacheHandle::new(),
            uv_rect_kind: UvRectKind::Rect,
            cache_handle: None,
            sub_pass: None,
        }
    }

    pub fn new_dynamic(
        size: DeviceIntSize,
        kind: RenderTaskKind,
    ) -> Self {
        assert!(!size.is_empty(), "Bad {} render task size: {:?}", kind.as_str(), size);
        RenderTask::new(
            RenderTaskLocation::Unallocated { size },
            kind,
        )
    }

    pub fn with_uv_rect_kind(mut self, uv_rect_kind: UvRectKind) -> Self {
        self.uv_rect_kind = uv_rect_kind;
        self
    }

    pub fn new_image(
        size: DeviceIntSize,
        request: ImageRequest,
    ) -> Self {
        // Note: this is a special constructor for image render tasks that does not
        // do the render task size sanity check. This is because with SWGL we purposefully
        // avoid tiling large images. There is no upload with SWGL so whatever was
        // successfully allocated earlier will be what shaders read, regardless of the size
        // and copying into tiles would only slow things down.
        // As a result we can run into very large images being added to the frame graph
        // (this is covered by a few reftests on the CI).

        RenderTask {
            location: RenderTaskLocation::CacheRequest { size, },
            children: TaskDependencies::new(),
            kind: RenderTaskKind::Image(request),
            free_after: PassId::MAX,
            render_on: PassId::MIN,
            uv_rect_handle: GpuCacheHandle::new(),
            uv_rect_kind: UvRectKind::Rect,
            cache_handle: None,
            sub_pass: None,
        }
    }


    #[cfg(test)]
    pub fn new_test(
        location: RenderTaskLocation,
        target: RenderTargetKind,
    ) -> Self {
        RenderTask {
            location,
            children: TaskDependencies::new(),
            kind: RenderTaskKind::Test(target),
            free_after: PassId::MAX,
            render_on: PassId::MIN,
            uv_rect_handle: GpuCacheHandle::new(),
            uv_rect_kind: UvRectKind::Rect,
            cache_handle: None,
            sub_pass: None,
        }
    }

    pub fn new_blit(
        size: DeviceIntSize,
        source: RenderTaskId,
        source_rect: DeviceIntRect,
        rg_builder: &mut RenderTaskGraphBuilder,
    ) -> RenderTaskId {
        // If this blit uses a render task as a source,
        // ensure it's added as a child task. This will
        // ensure it gets allocated in the correct pass
        // and made available as an input when this task
        // executes.

        let blit_task_id = rg_builder.add().init(RenderTask::new_dynamic(
            size,
            RenderTaskKind::Blit(BlitTask { source, source_rect }),
        ));

        rg_builder.add_dependency(blit_task_id, source);

        blit_task_id
    }

    // Construct a render task to apply a blur to a primitive.
    // The render task chain that is constructed looks like:
    //
    //    PrimitiveCacheTask: Draw the primitives.
    //           ^
    //           |
    //    DownscalingTask(s): Each downscaling task reduces the size of render target to
    //           ^            half. Also reduce the std deviation to half until the std
    //           |            deviation less than 4.0.
    //           |
    //           |
    //    VerticalBlurTask: Apply the separable vertical blur to the primitive.
    //           ^
    //           |
    //    HorizontalBlurTask: Apply the separable horizontal blur to the vertical blur.
    //           |
    //           +---- This is stored as the input task to the primitive shader.
    //
    pub fn new_blur(
        blur_std_deviation: DeviceSize,
        src_task_id: RenderTaskId,
        rg_builder: &mut RenderTaskGraphBuilder,
        target_kind: RenderTargetKind,
        mut blur_cache: Option<&mut BlurTaskCache>,
        blur_region: DeviceIntSize,
    ) -> RenderTaskId {
        // Adjust large std deviation value.
        let mut adjusted_blur_std_deviation = blur_std_deviation;
        let (blur_target_size, uv_rect_kind) = {
            let src_task = rg_builder.get_task(src_task_id);
            (src_task.location.size(), src_task.uv_rect_kind())
        };
        let mut adjusted_blur_target_size = blur_target_size;
        let mut downscaling_src_task_id = src_task_id;
        let mut scale_factor = 1.0;
        let mut n_downscales = 1;
        while adjusted_blur_std_deviation.width > MAX_BLUR_STD_DEVIATION &&
              adjusted_blur_std_deviation.height > MAX_BLUR_STD_DEVIATION {
            if adjusted_blur_target_size.width < MIN_DOWNSCALING_RT_SIZE ||
               adjusted_blur_target_size.height < MIN_DOWNSCALING_RT_SIZE {
                break;
            }
            adjusted_blur_std_deviation = adjusted_blur_std_deviation * 0.5;
            scale_factor *= 2.0;
            adjusted_blur_target_size = (blur_target_size.to_f32() / scale_factor).to_i32();

            let cached_task = match blur_cache {
                Some(ref mut cache) => cache.get(&BlurTaskKey::DownScale(n_downscales)).cloned(),
                None => None,
            };

            downscaling_src_task_id = cached_task.unwrap_or_else(|| {
                RenderTask::new_scaling(
                    downscaling_src_task_id,
                    rg_builder,
                    target_kind,
                    adjusted_blur_target_size,
                )
            });

            if let Some(ref mut cache) = blur_cache {
                cache.insert(BlurTaskKey::DownScale(n_downscales), downscaling_src_task_id);
            }

            n_downscales += 1;
        }


        let blur_key = BlurTaskKey::downscale_and_blur(n_downscales, adjusted_blur_std_deviation);

        let cached_task = match blur_cache {
            Some(ref mut cache) => cache.get(&blur_key).cloned(),
            None => None,
        };

        let blur_region = blur_region / (scale_factor as i32);

        let blur_task_id = cached_task.unwrap_or_else(|| {
            let blur_task_v = rg_builder.add().init(RenderTask::new_dynamic(
                adjusted_blur_target_size,
                RenderTaskKind::VerticalBlur(BlurTask {
                    blur_std_deviation: adjusted_blur_std_deviation.height,
                    target_kind,
                    blur_region,
                }),
            ).with_uv_rect_kind(uv_rect_kind));
            rg_builder.add_dependency(blur_task_v, downscaling_src_task_id);

            let task_id = rg_builder.add().init(RenderTask::new_dynamic(
                adjusted_blur_target_size,
                RenderTaskKind::HorizontalBlur(BlurTask {
                    blur_std_deviation: adjusted_blur_std_deviation.width,
                    target_kind,
                    blur_region,
                }),
            ).with_uv_rect_kind(uv_rect_kind));
            rg_builder.add_dependency(task_id, blur_task_v);

            task_id
        });

        if let Some(ref mut cache) = blur_cache {
            cache.insert(blur_key, blur_task_id);
        }

        blur_task_id
    }

    pub fn new_scaling(
        src_task_id: RenderTaskId,
        rg_builder: &mut RenderTaskGraphBuilder,
        target_kind: RenderTargetKind,
        size: DeviceIntSize,
    ) -> RenderTaskId {
        Self::new_scaling_with_padding(
            src_task_id,
            rg_builder,
            target_kind,
            size,
            DeviceIntSideOffsets::zero(),
        )
    }

    pub fn new_scaling_with_padding(
        source: RenderTaskId,
        rg_builder: &mut RenderTaskGraphBuilder,
        target_kind: RenderTargetKind,
        padded_size: DeviceIntSize,
        padding: DeviceIntSideOffsets,
    ) -> RenderTaskId {
        let uv_rect_kind = rg_builder.get_task(source).uv_rect_kind();

        let task_id = rg_builder.add().init(
            RenderTask::new_dynamic(
                padded_size,
                RenderTaskKind::Scaling(ScalingTask {
                    target_kind,
                    padding,
                }),
            ).with_uv_rect_kind(uv_rect_kind)
        );

        rg_builder.add_dependency(task_id, source);

        task_id
    }

    pub fn new_svg_filter(
        filter_primitives: &[FilterPrimitive],
        filter_datas: &[SFilterData],
        rg_builder: &mut RenderTaskGraphBuilder,
        content_size: DeviceIntSize,
        uv_rect_kind: UvRectKind,
        original_task_id: RenderTaskId,
        device_pixel_scale: DevicePixelScale,
    ) -> RenderTaskId {

        if filter_primitives.is_empty() {
            return original_task_id;
        }

        // Resolves the input to a filter primitive
        let get_task_input = |
            input: &FilterPrimitiveInput,
            filter_primitives: &[FilterPrimitive],
            rg_builder: &mut RenderTaskGraphBuilder,
            cur_index: usize,
            outputs: &[RenderTaskId],
            original: RenderTaskId,
            color_space: ColorSpace,
        | {
            // TODO(cbrewster): Not sure we can assume that the original input is sRGB.
            let (mut task_id, input_color_space) = match input.to_index(cur_index) {
                Some(index) => (outputs[index], filter_primitives[index].color_space),
                None => (original, ColorSpace::Srgb),
            };

            match (input_color_space, color_space) {
                (ColorSpace::Srgb, ColorSpace::LinearRgb) => {
                    task_id = RenderTask::new_svg_filter_primitive(
                        smallvec![task_id],
                        content_size,
                        uv_rect_kind,
                        SvgFilterInfo::SrgbToLinear,
                        rg_builder,
                    );
                },
                (ColorSpace::LinearRgb, ColorSpace::Srgb) => {
                    task_id = RenderTask::new_svg_filter_primitive(
                        smallvec![task_id],
                        content_size,
                        uv_rect_kind,
                        SvgFilterInfo::LinearToSrgb,
                        rg_builder,
                    );
                },
                _ => {},
            }

            task_id
        };

        let mut outputs = vec![];
        let mut cur_filter_data = 0;
        for (cur_index, primitive) in filter_primitives.iter().enumerate() {
            let render_task_id = match primitive.kind {
                FilterPrimitiveKind::Identity(ref identity) => {
                    // Identity does not create a task, it provides its input's render task
                    get_task_input(
                        &identity.input,
                        filter_primitives,
                        rg_builder,
                        cur_index,
                        &outputs,
                        original_task_id,
                        primitive.color_space
                    )
                }
                FilterPrimitiveKind::Blend(ref blend) => {
                    let input_1_task_id = get_task_input(
                        &blend.input1,
                        filter_primitives,
                        rg_builder,
                        cur_index,
                        &outputs,
                        original_task_id,
                        primitive.color_space
                    );
                    let input_2_task_id = get_task_input(
                        &blend.input2,
                        filter_primitives,
                        rg_builder,
                        cur_index,
                        &outputs,
                        original_task_id,
                        primitive.color_space
                    );

                    RenderTask::new_svg_filter_primitive(
                        smallvec![input_1_task_id, input_2_task_id],
                        content_size,
                        uv_rect_kind,
                        SvgFilterInfo::Blend(blend.mode),
                        rg_builder,
                    )
                },
                FilterPrimitiveKind::Flood(ref flood) => {
                    RenderTask::new_svg_filter_primitive(
                        smallvec![],
                        content_size,
                        uv_rect_kind,
                        SvgFilterInfo::Flood(flood.color),
                        rg_builder,
                    )
                }
                FilterPrimitiveKind::Blur(ref blur) => {
                    let width_std_deviation = blur.width * device_pixel_scale.0;
                    let height_std_deviation = blur.height * device_pixel_scale.0;
                    let input_task_id = get_task_input(
                        &blur.input,
                        filter_primitives,
                        rg_builder,
                        cur_index,
                        &outputs,
                        original_task_id,
                        primitive.color_space
                    );

                    RenderTask::new_blur(
                        DeviceSize::new(width_std_deviation, height_std_deviation),
                        // TODO: This is a hack to ensure that a blur task's input is always
                        // in the blur's previous pass.
                        RenderTask::new_svg_filter_primitive(
                            smallvec![input_task_id],
                            content_size,
                            uv_rect_kind,
                            SvgFilterInfo::Identity,
                            rg_builder,
                        ),
                        rg_builder,
                        RenderTargetKind::Color,
                        None,
                        content_size,
                    )
                }
                FilterPrimitiveKind::Opacity(ref opacity) => {
                    let input_task_id = get_task_input(
                        &opacity.input,
                        filter_primitives,
                        rg_builder,
                        cur_index,
                        &outputs,
                        original_task_id,
                        primitive.color_space
                    );

                    RenderTask::new_svg_filter_primitive(
                        smallvec![input_task_id],
                        content_size,
                        uv_rect_kind,
                        SvgFilterInfo::Opacity(opacity.opacity),
                        rg_builder,
                    )
                }
                FilterPrimitiveKind::ColorMatrix(ref color_matrix) => {
                    let input_task_id = get_task_input(
                        &color_matrix.input,
                        filter_primitives,
                        rg_builder,
                        cur_index,
                        &outputs,
                        original_task_id,
                        primitive.color_space
                    );

                    RenderTask::new_svg_filter_primitive(
                        smallvec![input_task_id],
                        content_size,
                        uv_rect_kind,
                        SvgFilterInfo::ColorMatrix(Box::new(color_matrix.matrix)),
                        rg_builder,
                    )
                }
                FilterPrimitiveKind::DropShadow(ref drop_shadow) => {
                    let input_task_id = get_task_input(
                        &drop_shadow.input,
                        filter_primitives,
                        rg_builder,
                        cur_index,
                        &outputs,
                        original_task_id,
                        primitive.color_space
                    );

                    let blur_std_deviation = drop_shadow.shadow.blur_radius * device_pixel_scale.0;
                    let offset = drop_shadow.shadow.offset * LayoutToWorldScale::new(1.0) * device_pixel_scale;

                    let offset_task_id = RenderTask::new_svg_filter_primitive(
                        smallvec![input_task_id],
                        content_size,
                        uv_rect_kind,
                        SvgFilterInfo::Offset(offset),
                        rg_builder,
                    );

                    let blur_task_id = RenderTask::new_blur(
                        DeviceSize::new(blur_std_deviation, blur_std_deviation),
                        offset_task_id,
                        rg_builder,
                        RenderTargetKind::Color,
                        None,
                        content_size,
                    );

                    RenderTask::new_svg_filter_primitive(
                        smallvec![input_task_id, blur_task_id],
                        content_size,
                        uv_rect_kind,
                        SvgFilterInfo::DropShadow(drop_shadow.shadow.color),
                        rg_builder,
                    )
                }
                FilterPrimitiveKind::ComponentTransfer(ref component_transfer) => {
                    let input_task_id = get_task_input(
                        &component_transfer.input,
                        filter_primitives,
                        rg_builder,
                        cur_index,
                        &outputs,
                        original_task_id,
                        primitive.color_space
                    );

                    let filter_data = &filter_datas[cur_filter_data];
                    cur_filter_data += 1;
                    if filter_data.is_identity() {
                        input_task_id
                    } else {
                        RenderTask::new_svg_filter_primitive(
                            smallvec![input_task_id],
                            content_size,
                            uv_rect_kind,
                            SvgFilterInfo::ComponentTransfer(filter_data.clone()),
                            rg_builder,
                        )
                    }
                }
                FilterPrimitiveKind::Offset(ref info) => {
                    let input_task_id = get_task_input(
                        &info.input,
                        filter_primitives,
                        rg_builder,
                        cur_index,
                        &outputs,
                        original_task_id,
                        primitive.color_space
                    );

                    let offset = info.offset * LayoutToWorldScale::new(1.0) * device_pixel_scale;
                    RenderTask::new_svg_filter_primitive(
                        smallvec![input_task_id],
                        content_size,
                        uv_rect_kind,
                        SvgFilterInfo::Offset(offset),
                        rg_builder,
                    )
                }
                FilterPrimitiveKind::Composite(info) => {
                    let input_1_task_id = get_task_input(
                        &info.input1,
                        filter_primitives,
                        rg_builder,
                        cur_index,
                        &outputs,
                        original_task_id,
                        primitive.color_space
                    );
                    let input_2_task_id = get_task_input(
                        &info.input2,
                        filter_primitives,
                        rg_builder,
                        cur_index,
                        &outputs,
                        original_task_id,
                        primitive.color_space
                    );

                    RenderTask::new_svg_filter_primitive(
                        smallvec![input_1_task_id, input_2_task_id],
                        content_size,
                        uv_rect_kind,
                        SvgFilterInfo::Composite(info.operator),
                        rg_builder,
                    )
                }
            };
            outputs.push(render_task_id);
        }

        // The output of a filter is the output of the last primitive in the chain.
        let mut render_task_id = *outputs.last().unwrap();

        // Convert to sRGB if needed
        if filter_primitives.last().unwrap().color_space == ColorSpace::LinearRgb {
            render_task_id = RenderTask::new_svg_filter_primitive(
                smallvec![render_task_id],
                content_size,
                uv_rect_kind,
                SvgFilterInfo::LinearToSrgb,
                rg_builder,
            );
        }

        render_task_id
    }

    pub fn new_svg_filter_primitive(
        tasks: TaskDependencies,
        target_size: DeviceIntSize,
        uv_rect_kind: UvRectKind,
        info: SvgFilterInfo,
        rg_builder: &mut RenderTaskGraphBuilder,
    ) -> RenderTaskId {
        let task_id = rg_builder.add().init(RenderTask::new_dynamic(
            target_size,
            RenderTaskKind::SvgFilter(SvgFilterTask {
                extra_gpu_cache_handle: None,
                info,
            }),
        ).with_uv_rect_kind(uv_rect_kind));

        for child_id in tasks {
            rg_builder.add_dependency(task_id, child_id);
        }

        task_id
    }

    pub fn add_sub_pass(
        &mut self,
        sub_pass: SubPass,
    ) {
        assert!(self.sub_pass.is_none(), "multiple sub-passes are not supported for now");
        self.sub_pass = Some(sub_pass);
    }

    /// Creates render tasks from PictureCompositeMode::SVGFEGraph.
    ///
    /// The interesting parts of the handling of SVG filters are:
    /// * scene_building.rs : wrap_prim_with_filters
    /// * picture.rs : get_coverage_svgfe
    /// * render_task.rs : new_svg_filter_graph (you are here)
    /// * render_target.rs : add_svg_filter_node_instances
    pub fn new_svg_filter_graph(
        filter_nodes: &[(FilterGraphNode, FilterGraphOp)],
        rg_builder: &mut RenderTaskGraphBuilder,
        gpu_cache: &mut GpuCache,
        data_stores: &mut DataStores,
        _uv_rect_kind: UvRectKind,
        original_task_id: RenderTaskId,
        source_subregion: LayoutRect,
        target_subregion: LayoutRect,
        prim_subregion: LayoutRect,
        subregion_to_device_scale_x: f32,
        subregion_to_device_scale_y: f32,
        subregion_to_device_offset_x: f32,
        subregion_to_device_offset_y: f32,
    ) -> RenderTaskId {
        const BUFFER_LIMIT: usize = SVGFE_GRAPH_MAX;
        let mut task_by_buffer_id: [RenderTaskId; BUFFER_LIMIT] = [RenderTaskId::INVALID; BUFFER_LIMIT];
        let mut subregion_by_buffer_id: [LayoutRect; BUFFER_LIMIT] = [LayoutRect::zero(); BUFFER_LIMIT];
        // If nothing replaces this value (all node subregions are empty), we
        // can just return the original picture
        let mut output_task_id = original_task_id;

        // By this point we assume the following about the graph:
        // * BUFFER_LIMIT here should be >= BUFFER_LIMIT in the scene_building.rs code.
        // * input buffer id < output buffer id
        // * output buffer id between 0 and BUFFER_LIMIT
        // * the number of filter_datas matches the number of kept nodes with op
        //   SVGFEComponentTransfer.
        //
        // These assumptions are verified with asserts in this function as
        // appropriate.

        // Make a UvRectKind::Quad that represents a task for a node, which may
--> --------------------

--> maximum size reached

--> --------------------

[ Seitenstruktur0.62Drucken  etwas mehr zur Ethik  ]

                                                                                                                                                                                                                                                                                                                                                                                                     


Neuigkeiten

     Aktuelles
     Motto des Tages

Software

     Produkte
     Quellcodebibliothek

Aktivitäten

     Artikel über Sicherheit
     Anleitung zur Aktivierung von SSL

Muße

     Gedichte
     Musik
     Bilder

Jenseits des Üblichen ....

Besucherstatistik

Besucherstatistik

Monitoring

Montastic status badge