webrender/prim_store/

image.rs

/* 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::{
    AlphaType, ColorDepth, ColorF, ColorRange, ColorU, ExternalImageData, ExternalImageType, ImageBufferKind, ImageKey as ApiImageKey, ImageRendering, PremultipliedColorF, RasterSpace, Shadow, YuvColorSpace, YuvFormat
};
use api::units::*;
use euclid::point2;
use crate::clip::{ClipChainInstance, ClipIntern};
use crate::command_buffer::CommandBufferIndex;
use crate::gpu_types::{ImageBrushPrimitiveData, YuvPrimitive};
use crate::pattern::image::ImagePattern;
use crate::quad::QuadTransformState;
use crate::renderer::{GpuBufferAddress, GpuBufferBuilderF, GpuBufferWriterF};
use crate::scene_building::{CreateShadow, IsVisible};
use crate::frame_builder::{FrameBuildingContext, FrameBuildingState, PictureContext};
use crate::intern::{DataStore, Handle as InternHandle, InternDebug, Internable};
use crate::internal_types::LayoutPrimitiveInfo;
use crate::prim_store::{
    EdgeMask, InternablePrimitive, PrimKey, PrimTemplate, PrimTemplateCommonData, PrimitiveInstanceIndex, PrimitiveKind, PrimitiveOpacity, PrimitiveScratchBuffer, PrimitiveStore, SizeKey
};
use crate::prim_store::storage;
use crate::render_target::RenderTargetKind;
use crate::render_task_graph::RenderTaskId;
use crate::render_task::RenderTask;
use crate::render_task_cache::{
    RenderTaskCacheKey, RenderTaskCacheKeyKind, RenderTaskParent
};
use crate::resource_cache::{ImageRequest, ImageProperties, ResourceCache};
use crate::visibility::compute_conservative_visible_rect;
use crate::spatial_tree::SpatialNodeIndex;
use crate::{image_tiling, quad};

#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct VisibleImageTile {
    pub src_color: RenderTaskId,
    pub edge_flags: EdgeMask,
    pub local_rect: LayoutRect,
    pub local_clip_rect: LayoutRect,
}

// Key that identifies a unique (partial) image that is being
// stored in the render task cache.
#[derive(Debug, Copy, Clone, Eq, Hash, PartialEq)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct ImageCacheKey {
    pub request: ImageRequest,
    pub texel_rect: Option<DeviceIntRect>,
}

/// Per-frame scratch data for an Image primitive. Captures the per-frame
/// outputs of `ImageData::update`: the source render task (or a Range of
/// per-tile tasks for tiled images), normalized-uvs flag, image
/// adjustment from snapshots, and a tight local clip rect derived from
/// the prim's clip chain. Pushed during prepare and read by batch.
#[derive(Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
pub struct ImageScratch {
    /// Range into `PrimitiveFrameScratch.visible_image_tiles` for tiled
    /// images. Empty for non-tiled images.
    pub visible_tiles: storage::Range<VisibleImageTile>,
    /// Source render task for non-tiled images.
    pub src_color: Option<RenderTaskId>,
    /// Whether to render with normalized UVs (set for some external
    /// images).
    pub normalized_uvs: bool,
    /// Adjustment applied when sampling from a wider source (e.g.
    /// snapshot images).
    pub adjustment: AdjustedImageSource,
    /// Tight local clip rect derived from the prim's clip chain. We
    /// rely on having this in cases where decomposing repeated images
    /// can produce primitives that partially cover the original image
    /// rect, and for snapshot images where the snapshot area is
    /// tighter than the rasterized area.
    pub tight_local_clip_rect: LayoutRect,
    /// Whether this draw needs the repetition-capable image shader.
    /// Set to false when the stretch_size covers the prim (no tiling)
    /// or when the image was decomposed into per-tile prims at
    /// scene-build time. Read by batch to choose between brush_image
    /// and brush_fast_image.
    pub may_need_repetition: bool,
    /// Address of the per-instance image-brush GPU block. Lives here
    /// (rather than on the template's `PrimTemplateCommonData`) because
    /// the resolved stretch size and adjustment-mapped values vary per
    /// instance, even when many instances share a single template.
    pub gpu_address: GpuBufferAddress,
}

impl ImageScratch {
    pub fn empty() -> Self {
        ImageScratch {
            visible_tiles: storage::Range::empty(),
            src_color: None,
            normalized_uvs: false,
            adjustment: AdjustedImageSource::new(),
            tight_local_clip_rect: LayoutRect::zero(),
            may_need_repetition: true,
            gpu_address: GpuBufferAddress::INVALID,
        }
    }
}

/// How to compute the effective stretch size for an image primitive, per
/// axis. `FillsPrim` resolves to the (snapped) prim-rect extent at
/// frame-build so the value sent to the GPU lands on the snapped pixel
/// grid. `Explicit` keeps the gecko-specified value verbatim. Per-axis
/// because gecko can specify a background tile that fills the prim on
/// one axis but tiles on the other (e.g. `background-repeat: repeat-y`
/// with `background-size: 116.8px 0.8px`).
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Debug, Clone, Copy, Eq, PartialEq, Hash, MallocSizeOf)]
pub struct StretchSizeKey {
    pub size: SizeKey,
    pub fills_width: bool,
    pub fills_height: bool,
}

impl StretchSizeKey {
    /// Both axes fill the prim. The stored size is unused; normalised
    /// to zero so different prim sizes still intern to the same key.
    pub fn fills_prim() -> Self {
        StretchSizeKey {
            size: LayoutSize::zero().into(),
            fills_width: true,
            fills_height: true,
        }
    }
}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Debug, Clone, Copy, MallocSizeOf)]
pub struct StretchSize {
    pub size: LayoutSize,
    pub fills_width: bool,
    pub fills_height: bool,
}

impl From<StretchSizeKey> for StretchSize {
    fn from(k: StretchSizeKey) -> Self {
        StretchSize {
            size: k.size.into(),
            fills_width: k.fills_width,
            fills_height: k.fills_height,
        }
    }
}

impl StretchSize {
    /// Resolve to the LayoutSize used for the GPU shader and tiling math.
    /// Per-axis: an axis flagged `fills_*` resolves to the snapped prim
    /// rect's extent on that axis; the other axis keeps the stored size.
    pub fn resolve(self, prim_rect: &LayoutRect) -> LayoutSize {
        let prim_size = prim_rect.size();
        LayoutSize::new(
            if self.fills_width { prim_size.width } else { self.size.width },
            if self.fills_height { prim_size.height } else { self.size.height },
        )
    }
}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Debug, Clone, Eq, PartialEq, MallocSizeOf, Hash)]
pub struct Image {
    pub key: ApiImageKey,
    pub stretch_size: StretchSizeKey,
    pub tile_spacing: SizeKey,
    pub color: ColorU,
    pub image_rendering: ImageRendering,
    pub alpha_type: AlphaType,
}

pub type ImageKey = PrimKey<Image>;

impl ImageKey {
    pub fn new(
        info: &LayoutPrimitiveInfo,
        image: Image,
    ) -> Self {
        ImageKey {
            common: info.into(),
            kind: image,
        }
    }
}

impl InternDebug for ImageKey {}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Debug, MallocSizeOf)]
pub struct ImageData {
    pub key: ApiImageKey,
    pub stretch_size: StretchSize,
    pub tile_spacing: LayoutSize,
    pub color: ColorF,
    pub image_rendering: ImageRendering,
    pub alpha_type: AlphaType,
}

impl From<Image> for ImageData {
    fn from(image: Image) -> Self {
        ImageData {
            key: image.key,
            color: image.color.into(),
            stretch_size: image.stretch_size.into(),
            tile_spacing: image.tile_spacing.into(),
            image_rendering: image.image_rendering,
            alpha_type: image.alpha_type,
        }
    }
}

impl ImageData {
    /// Update the GPU cache for a given primitive template. This may be called multiple
    /// times per frame, by each primitive reference that refers to this interned
    /// template. The initial request call to the GPU cache ensures that work is only
    /// done if the cache entry is invalid (due to first use or eviction).
    pub fn update(
        &mut self,
        common: &mut PrimTemplateCommonData,
        prim_instance_index: PrimitiveInstanceIndex,
        prim_spatial_node_index: SpatialNodeIndex,
        frame_state: &mut FrameBuildingState,
        frame_context: &FrameBuildingContext,
        prim_rect: LayoutRect,
        scratch: &mut PrimitiveScratchBuffer,
    ) -> storage::Index<ImageScratch> {

        let image_properties = frame_state
            .resource_cache
            .get_image_properties(self.key);

        common.opacity = match &image_properties {
            Some(properties) => {
                if properties.descriptor.is_opaque() {
                    PrimitiveOpacity::from_alpha(self.color.a)
                } else {
                    PrimitiveOpacity::translucent()
                }
            }
            None => PrimitiveOpacity::opaque(),
        };

        let request = ImageRequest {
            key: self.key,
            rendering: self.image_rendering,
            tile: None,
        };

        // Tighten the clip rect because decomposing the repeated image can
        // produce primitives that are partially covering the original image
        // rect and we want to clip these extra parts out.
        // We also rely on having a tight clip rect in some cases other than
        // tiled/repeated images, for example when rendering a snapshot image
        // where the snapshot area is tighter than the rasterized area.
        let tight_clip_rect = scratch.frame.draws[prim_instance_index.0 as usize]
            .clip_chain
            .local_clip_rect
            .intersection(&prim_rect).unwrap();

        let effective_stretch_size = self.stretch_size.resolve(&prim_rect);

        let mut image_scratch = ImageScratch::empty();
        image_scratch.tight_local_clip_rect = tight_clip_rect;
        if effective_stretch_size.width >= prim_rect.size().width
            && effective_stretch_size.height >= prim_rect.size().height
        {
            image_scratch.may_need_repetition = false;
        }

        match image_properties {
            // Non-tiled (most common) path.
            Some(ImageProperties { tiling: None, ref descriptor, ref external_image, adjustment, .. }) => {
                image_scratch.adjustment = adjustment;

                let mut size = frame_state.resource_cache.request_image(
                    request,
                    &mut frame_state.frame_gpu_data.f32,
                );

                let mut task_id = frame_state.rg_builder.add().init(
                    RenderTask::new_image(size, request, false)
                );

                if let Some(external_image) = external_image {
                    // On some devices we cannot render from an ImageBufferKind::TextureExternal
                    // source using most shaders, so must peform a copy to a regular texture first.
                    let requires_copy = frame_context.fb_config.external_images_require_copy &&
                        external_image.image_type ==
                            ExternalImageType::TextureHandle(ImageBufferKind::TextureExternal);

                    if requires_copy {
                        let target_kind = if descriptor.format.bytes_per_pixel() == 1 {
                            RenderTargetKind::Alpha
                        } else {
                            RenderTargetKind::Color
                        };

                        task_id = RenderTask::new_scaling(
                            task_id,
                            frame_state.rg_builder,
                            target_kind,
                            size
                        );

                        frame_state.surface_builder.add_child_render_task(
                            task_id,
                            frame_state.rg_builder,
                        );
                    }

                    // Ensure the instance is rendered using normalized_uvs if the external image
                    // requires so. If we inserted a scale above this is not required as the
                    // instance is rendered from a render task rather than the external image.
                    if !requires_copy {
                        image_scratch.normalized_uvs = external_image.normalized_uvs;
                    }
                }

                // Every frame, for cached items, we need to request the render
                // task cache item. The closure will be invoked on the first
                // time through, and any time the render task output has been
                // evicted from the texture cache.
                if self.tile_spacing == LayoutSize::zero() {
                    // Most common case.
                    image_scratch.src_color = Some(task_id);
                } else {
                    let padding = DeviceIntSideOffsets::new(
                        0,
                        (self.tile_spacing.width * size.width as f32 / effective_stretch_size.width) as i32,
                        (self.tile_spacing.height * size.height as f32 / effective_stretch_size.height) as i32,
                        0,
                    );

                    size.width += padding.horizontal();
                    size.height += padding.vertical();

                    if padding != DeviceIntSideOffsets::zero() {
                        common.opacity = PrimitiveOpacity::translucent();
                    }

                    let image_cache_key = ImageCacheKey {
                        request,
                        texel_rect: None,
                    };
                    let target_kind = if descriptor.format.bytes_per_pixel() == 1 {
                        RenderTargetKind::Alpha
                    } else {
                        RenderTargetKind::Color
                    };

                    // Request a pre-rendered image task.
                    let cached_task_handle = frame_state.resource_cache.request_render_task(
                        Some(RenderTaskCacheKey {
                            origin: DeviceIntPoint::zero(),
                            size,
                            kind: RenderTaskCacheKeyKind::Image(image_cache_key),
                        }),
                        descriptor.is_opaque(),
                        RenderTaskParent::Surface,
                        &mut frame_state.frame_gpu_data.f32,
                        frame_state.rg_builder,
                        &mut frame_state.surface_builder,
                        &mut |rg_builder, _| {
                            // Create a task to blit from the texture cache to
                            // a normal transient render task surface.
                            // TODO: figure out if/when we can do a blit instead.
                            let cache_to_target_task_id = RenderTask::new_scaling_with_padding(
                                task_id,
                                rg_builder,
                                target_kind,
                                size,
                                padding,
                            );

                            // Create a task to blit the rect from the child render
                            // task above back into the right spot in the persistent
                            // render target cache.
                            RenderTask::new_blit(
                                size,
                                cache_to_target_task_id,
                                size.into(),
                                rg_builder,
                            )
                        }
                    );

                    image_scratch.src_color = Some(cached_task_handle);
                }
            }
            // Tiled image path.
            Some(ImageProperties { tiling: Some(tile_size), visible_rect, .. }) => {
                // we'll  have a source handle per visible tile instead.
                image_scratch.src_color = None;

                // TODO: rename the blob's visible_rect into something that doesn't conflict
                // with the terminology we use during culling since it's not really the same
                // thing.
                let active_rect = visible_rect;

                let visible_rect = compute_conservative_visible_rect(
                    &scratch.frame.draws[prim_instance_index.0 as usize].clip_chain,
                    frame_state.current_dirty_region().combined,
                    frame_state.current_dirty_region().visibility_spatial_node,
                    prim_spatial_node_index,
                    frame_context.spatial_tree,
                );

                let base_edge_flags = edge_flags_for_tile_spacing(&self.tile_spacing);

                let stride = effective_stretch_size + self.tile_spacing;

                // We are performing the decomposition on the CPU here, no need to
                // have it in the shader.
                image_scratch.may_need_repetition = false;

                let repetitions = image_tiling::repetitions(
                    &prim_rect,
                    &visible_rect,
                    stride,
                );

                let tiles_open = scratch.frame.visible_image_tiles.open_range();
                for image_tiling::Repetition { origin, edge_flags } in repetitions {
                    let edge_flags = base_edge_flags | edge_flags;

                    let layout_image_rect = LayoutRect::from_origin_and_size(
                        origin,
                        effective_stretch_size,
                    );

                    let tiles = image_tiling::tiles(
                        &layout_image_rect,
                        &visible_rect,
                        &active_rect,
                        tile_size as i32,
                    );

                    for tile in tiles {
                        let request = request.with_tile(tile.offset);
                        let size = frame_state.resource_cache.request_image(
                            request,
                            &mut frame_state.frame_gpu_data.f32,
                        );

                        let task_id = frame_state.rg_builder.add().init(
                            RenderTask::new_image(size, request, false)
                        );

                        scratch.frame.visible_image_tiles.push(VisibleImageTile {
                            src_color: task_id,
                            edge_flags: tile.edge_flags & edge_flags,
                            local_rect: tile.rect,
                            local_clip_rect: tight_clip_rect,
                        });
                    }
                }
                image_scratch.visible_tiles = scratch.frame.visible_image_tiles.close_range(tiles_open);

                if image_scratch.visible_tiles.is_empty() {
                    // Mark as invisible
                    scratch.frame.draws[prim_instance_index.0 as usize].reset();
                }
            }
            None => {
                image_scratch.src_color = None;
            }
        }

        if let Some(task_id) = frame_state.image_dependencies.get(&self.key) {
            frame_state.surface_builder.add_child_render_task(
                *task_id,
                frame_state.rg_builder
            );
        }

        let mut writer = frame_state.frame_gpu_data.f32.write_blocks(3);
        self.write_prim_gpu_blocks(&image_scratch.adjustment, effective_stretch_size, &mut writer);
        image_scratch.gpu_address = writer.finish();

        scratch.frame.images.push(image_scratch)
    }

    pub fn write_prim_gpu_blocks(
        &self,
        adjustment: &AdjustedImageSource,
        stretch_size: LayoutSize,
        writer: &mut GpuBufferWriterF,
    ) {
        let stretch_size = adjustment.map_stretch_size(stretch_size)
             + self.tile_spacing;

        writer.push(&ImageBrushPrimitiveData {
            color: self.color.premultiplied(),
            background_color: PremultipliedColorF::WHITE,
            stretch_size,
        });
    }
}

pub fn prepare_image_quads(
    prim_rect: &LayoutRect,
    common_data: &PrimTemplateCommonData,
    image_data: &ImageData,
    clip_chain: &ClipChainInstance,
    prim_instance_index: PrimitiveInstanceIndex,
    quad_transform: &mut QuadTransformState,
    frame_context: &FrameBuildingContext,
    pic_context: &PictureContext,
    targets: &[CommandBufferIndex],
    interned_clips: &DataStore<ClipIntern>,
    frame_state: &mut FrameBuildingState,
    scratch: &mut PrimitiveScratchBuffer,
) {
    let image_properties = frame_state
        .resource_cache
        .get_image_properties(image_data.key);

    let Some(image_properties) = image_properties else {
        return;
    };

    let src_is_opaque = image_properties.descriptor.is_opaque()
        && common_data.opacity.is_opaque
        && image_data.color.a >= 0.9999;

    let premultiplied = image_data.alpha_type == AlphaType::PremultipliedAlpha;

    // Tighten the clip rect because decomposing the repeated image can
    // produce primitives that are partially covering the original image
    // rect and we want to clip these extra parts out.
    // We also rely on having a tight clip rect in some cases other than
    // tiled/repeated images, for example when rendering a snapshot image
    // where the snapshot area is tighter than the rasterized area.
    let tight_clip_rect = clip_chain
        .local_clip_rect
        .intersection(&prim_rect)
        .unwrap();

    let request = ImageRequest {
        key: image_data.key,
        rendering: image_data.image_rendering,
        tile: None,
    };

    let mut sampler_kind = ImageBufferKind::Texture2D;
    if let Some(ExternalImageData { image_type: ExternalImageType::TextureHandle(kind), .. }) = image_properties.external_image {
        sampler_kind = kind;
    }


    match image_properties.tiling {
        // Non-tiled (most common) path.
        None => {
            let size = frame_state.resource_cache.request_image(
                request,
                &mut frame_state.frame_gpu_data.f32,
            );

            let effective_stretch_size = image_data.stretch_size.resolve(prim_rect);
            let prim_rect = image_properties.adjustment.map_local_rect(&prim_rect);
            let stretch_size = image_properties.adjustment.map_stretch_size(effective_stretch_size);

            let mut src_task_id = frame_state.rg_builder.add().init(
                RenderTask::new_image(size, request, false)
            );

            if let Some(external_image) = image_properties.external_image {
                // On some devices we cannot render from an ImageBufferKind::TextureExternal
                // source using most shaders, so must perform a copy to a regular texture first.
                let requires_copy = frame_context.fb_config.external_images_require_copy
                    && external_image.image_type
                        == ExternalImageType::TextureHandle(ImageBufferKind::TextureExternal);

                if requires_copy {
                    let target_kind = if image_properties.descriptor.format.bytes_per_pixel() == 1 {
                        RenderTargetKind::Alpha
                    } else {
                        RenderTargetKind::Color
                    };

                    src_task_id = RenderTask::new_scaling(
                        src_task_id,
                        frame_state.rg_builder,
                        target_kind,
                        size,
                    );

                    frame_state.surface_builder.add_child_render_task(
                        src_task_id,
                        frame_state.rg_builder,
                    );

                    sampler_kind = ImageBufferKind::Texture2D;
                }
            }

            let image_pattern = ImagePattern {
                src_task_id,
                src_is_opaque,
                premultiplied,
                sampler_kind,
                color: image_data.color,
            };

            quad::prepare_repeatable_quad(
                &image_pattern,
                &prim_rect,
                &tight_clip_rect,
                stretch_size,
                image_data.tile_spacing,
                common_data.aligned_aa_edges,
                common_data.transformed_aa_edges,
                prim_instance_index,
                &None,
                clip_chain,
                quad_transform,
                frame_context,
                pic_context,
                targets,
                interned_clips,
                frame_state,
                scratch,
            );
        }
        Some(tile_size) => {
            // TODO: rename the blob's visible_rect into something that doesn't conflict
            // with the terminology we use during culling since it's not really the same
            // thing.
            let active_rect = image_properties.visible_rect;
            let visible_rect = compute_conservative_visible_rect(
                &scratch.frame.draws[prim_instance_index.0 as usize].clip_chain,
                frame_state.current_dirty_region().combined,
                frame_state.current_dirty_region().visibility_spatial_node,
                quad_transform.prim_spatial_node_index(),
                frame_context.spatial_tree,
            );

            let effective_stretch_size = image_data.stretch_size.resolve(prim_rect);
            let stride = effective_stretch_size + image_data.tile_spacing;

            let repetitions = image_tiling::repetitions(
                prim_rect,
                &visible_rect,
                stride,
            );

            let base_edge_flags = edge_flags_for_tile_spacing(&image_data.tile_spacing);

            for image_tiling::Repetition { origin, edge_flags } in repetitions {
                let rep_edge_flags = base_edge_flags & edge_flags;

                let layout_image_rect = LayoutRect::from_origin_and_size(
                    origin,
                    effective_stretch_size,
                );

                let tiles = image_tiling::tiles(
                    &layout_image_rect,
                    &visible_rect,
                    &active_rect,
                    tile_size as i32,
                );

                for tile in tiles {
                    let request = request.with_tile(tile.offset);
                    let size = frame_state.resource_cache.request_image(
                        request,
                        &mut frame_state.frame_gpu_data.f32,
                    );

                    let tile_edge_flags = rep_edge_flags & tile.edge_flags;
                    let aligned_aa_edges = tile_edge_flags & common_data.aligned_aa_edges;
                    let transformed_aa_edges = tile_edge_flags & common_data.transformed_aa_edges;

                    let src_task_id = frame_state.rg_builder.add().init(
                        RenderTask::new_image(size, request, false)
                    );

                    let image_pattern = ImagePattern {
                        src_task_id,
                        src_is_opaque,
                        premultiplied,
                        sampler_kind,
                        color: image_data.color,
                    };

                    quad::prepare_quad(
                        &image_pattern,
                        &tile.rect,
                        &tight_clip_rect,
                        aligned_aa_edges,
                        transformed_aa_edges,
                        prim_instance_index,
                        &None,
                        clip_chain,
                        quad_transform,
                        frame_context,
                        pic_context,
                        targets,
                        interned_clips,
                        frame_state,
                        scratch,
                    );
                }
            }
        }
    }
}

fn edge_flags_for_tile_spacing(tile_spacing: &LayoutSize) -> EdgeMask {
    let mut flags = EdgeMask::empty();

    if tile_spacing.width > 0.0 {
        flags |= EdgeMask::LEFT | EdgeMask::RIGHT;
    }
    if tile_spacing.height > 0.0 {
        flags |= EdgeMask::TOP | EdgeMask::BOTTOM;
    }

    flags
}

pub type ImageTemplate = PrimTemplate<ImageData>;

impl From<ImageKey> for ImageTemplate {
    fn from(image: ImageKey) -> Self {
        let common = PrimTemplateCommonData::with_key_common(image.common);

        ImageTemplate {
            common,
            kind: image.kind.into(),
        }
    }
}

pub type ImageDataHandle = InternHandle<Image>;

impl Internable for Image {
    type Key = ImageKey;
    type StoreData = ImageTemplate;
    type InternData = ();
    const PROFILE_COUNTER: usize = crate::profiler::INTERNED_IMAGES;
}

impl InternablePrimitive for Image {
    fn into_key(
        self,
        info: &LayoutPrimitiveInfo,
    ) -> ImageKey {
        ImageKey::new(info, self)
    }

    fn make_instance_kind(
        _key: ImageKey,
        data_handle: ImageDataHandle,
        _prim_store: &mut PrimitiveStore,
    ) -> PrimitiveKind {
        PrimitiveKind::Image {
            data_handle,
        }
    }
}

impl CreateShadow for Image {
    fn create_shadow(
        &self,
        shadow: &Shadow,
        _: bool,
        _: RasterSpace,
    ) -> Self {
        Image {
            tile_spacing: self.tile_spacing,
            stretch_size: self.stretch_size,
            key: self.key,
            image_rendering: self.image_rendering,
            alpha_type: self.alpha_type,
            color: shadow.color.into(),
        }
    }
}

impl IsVisible for Image {
    fn is_visible(&self) -> bool {
        true
    }
}

/// Represents an adjustment to apply to an image primitive.
/// This can be used to compensate for a difference between the bounds of
/// the images expected by the primitive and the bounds that were actually
/// drawn in the texture cache.
///
/// This happens when rendering snapshot images: A picture is marked so that
/// a specific reference area in layout space can be rendered as an image.
/// However, the bounds of the rasterized area of the picture typically differ
/// from that reference area.
///
/// The adjustment is stored as 4 floats (x0, y0, x1, y1) that represent a
/// transformation of the primitve's local rect such that:
///
/// ```ignore
/// adjusted_rect.min = prim_rect.min + prim_rect.size() * (x0, y0);
/// adjusted_rect.max = prim_rect.max + prim_rect.size() * (x1, y1);
/// ```
#[derive(Copy, Clone, Debug)]
#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
pub struct AdjustedImageSource {
    x0: f32,
    y0: f32,
    x1: f32,
    y1: f32,
}

impl AdjustedImageSource {
    /// The "identity" adjustment.
    pub fn new() -> Self {
        AdjustedImageSource {
            x0: 0.0,
            y0: 0.0,
            x1: 0.0,
            y1: 0.0,
        }
    }

    /// An adjustment to render an image item defined in function of the `reference`
    /// rect whereas the `actual` rect was cached instead.
    pub fn from_rects(reference: &LayoutRect, actual: &LayoutRect) -> Self {
        let ref_size = reference.size();
        let min_offset = reference.min.to_vector();
        let max_offset = reference.max.to_vector();
        AdjustedImageSource {
            x0: (actual.min.x - min_offset.x) / ref_size.width,
            y0: (actual.min.y - min_offset.y) / ref_size.height,
            x1: (actual.max.x - max_offset.x) / ref_size.width,
            y1: (actual.max.y - max_offset.y) / ref_size.height,
        }
    }

    /// Adjust the primitive's local rect.
    pub fn map_local_rect(&self, rect: &LayoutRect) -> LayoutRect {
        let w = rect.width();
        let h = rect.height();
        LayoutRect {
            min: point2(
                rect.min.x + w * self.x0,
                rect.min.y + h * self.y0,
            ),
            max: point2(
                rect.max.x + w * self.x1,
                rect.max.y + h * self.y1,
            ),
        }
    }

    /// The stretch size has to be adjusted as well because it is defined
    /// using the snapshot area as reference but will stretch the rasterized
    /// area instead.
    ///
    /// It has to be scaled by a factor of (adjusted.size() / prim_rect.size()).
    /// We derive the formula in function of the adjustment factors:
    ///
    /// ```ignore
    /// factor = (adjusted.max - adjusted.min) / (w, h)
    ///        = (rect.max + (w, h) * (x1, y1) - (rect.min + (w, h) * (x0, y0))) / (w, h)
    ///        = ((w, h) + (w, h) * (x1, y1) - (w, h) * (x0, y0)) / (w, h)
    ///        = (1.0, 1.0) + (x1, y1) - (x0, y0)
    /// ```
    pub fn map_stretch_size(&self, size: LayoutSize) -> LayoutSize {
        LayoutSize::new(
            size.width * (1.0 + self.x1 - self.x0),
            size.height * (1.0 + self.y1 - self.y0),
        )
    }
}

////////////////////////////////////////////////////////////////////////////////

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(Debug, Clone, Eq, MallocSizeOf, PartialEq, Hash)]
pub struct YuvImage {
    pub color_depth: ColorDepth,
    pub yuv_key: [ApiImageKey; 3],
    pub format: YuvFormat,
    pub color_space: YuvColorSpace,
    pub color_range: ColorRange,
    pub image_rendering: ImageRendering,
}

pub type YuvImageKey = PrimKey<YuvImage>;

impl YuvImageKey {
    pub fn new(
        info: &LayoutPrimitiveInfo,
        yuv_image: YuvImage,
    ) -> Self {
        YuvImageKey {
            common: info.into(),
            kind: yuv_image,
        }
    }
}

impl InternDebug for YuvImageKey {}

#[cfg_attr(feature = "capture", derive(Serialize))]
#[cfg_attr(feature = "replay", derive(Deserialize))]
#[derive(MallocSizeOf)]
pub struct YuvImageData {
    pub color_depth: ColorDepth,
    pub yuv_key: [ApiImageKey; 3],
    pub src_yuv: [Option<RenderTaskId>; 3],
    pub format: YuvFormat,
    pub color_space: YuvColorSpace,
    pub color_range: ColorRange,
    pub image_rendering: ImageRendering,
}

impl From<YuvImage> for YuvImageData {
    fn from(image: YuvImage) -> Self {
        YuvImageData {
            color_depth: image.color_depth,
            yuv_key: image.yuv_key,
            src_yuv: [None, None, None],
            format: image.format,
            color_space: image.color_space,
            color_range: image.color_range,
            image_rendering: image.image_rendering,
        }
    }
}

impl YuvImageData {
    /// Update the GPU cache for a given primitive template. This may be called multiple
    /// times per frame, by each primitive reference that refers to this interned
    /// template. The initial request call to the GPU cache ensures that work is only
    /// done if the cache entry is invalid (due to first use or eviction).
    pub fn update(
        &mut self,
        common: &mut PrimTemplateCommonData,
        is_composited: bool,
        frame_state: &mut FrameBuildingState,
    ) {

        self.src_yuv = [ None, None, None ];

        let channel_num = self.format.get_plane_num();
        debug_assert!(channel_num <= 3);
        for channel in 0 .. channel_num {
            let request = ImageRequest {
                key: self.yuv_key[channel],
                rendering: self.image_rendering,
                tile: None,
            };

            let size = frame_state.resource_cache.request_image(
                request,
                &mut frame_state.frame_gpu_data.f32,
            );

            let task_id = frame_state.rg_builder.add().init(
                RenderTask::new_image(
                    size,
                    request,
                    is_composited,
                )
            );

            self.src_yuv[channel] = Some(task_id);
        }

        let mut writer = frame_state.frame_gpu_data.f32.write_blocks(1);
        self.write_prim_gpu_blocks(&mut writer);
        common.gpu_buffer_address = writer.finish();

    // YUV images never have transparency
        common.opacity = PrimitiveOpacity::opaque();
    }

    pub fn request_resources(
        &mut self,
        resource_cache: &mut ResourceCache,
        gpu_buffer: &mut GpuBufferBuilderF,
    ) {
        let channel_num = self.format.get_plane_num();
        debug_assert!(channel_num <= 3);
        for channel in 0 .. channel_num {
            resource_cache.request_image(
                ImageRequest {
                    key: self.yuv_key[channel],
                    rendering: self.image_rendering,
                    tile: None,
                },
                gpu_buffer,
            );
        }
    }

    pub fn write_prim_gpu_blocks(&self, writer: &mut GpuBufferWriterF) {
        writer.push(&YuvPrimitive {
            channel_bit_depth: self.color_depth.bit_depth(),
            color_space: self.color_space.with_range(self.color_range),
            yuv_format: self.format,
        });
    }
}

pub type YuvImageTemplate = PrimTemplate<YuvImageData>;

impl From<YuvImageKey> for YuvImageTemplate {
    fn from(image: YuvImageKey) -> Self {
        let common = PrimTemplateCommonData::with_key_common(image.common);

        YuvImageTemplate {
            common,
            kind: image.kind.into(),
        }
    }
}

pub type YuvImageDataHandle = InternHandle<YuvImage>;

impl Internable for YuvImage {
    type Key = YuvImageKey;
    type StoreData = YuvImageTemplate;
    type InternData = ();
    const PROFILE_COUNTER: usize = crate::profiler::INTERNED_YUV_IMAGES;
}

impl InternablePrimitive for YuvImage {
    fn into_key(
        self,
        info: &LayoutPrimitiveInfo,
    ) -> YuvImageKey {
        YuvImageKey::new(info, self)
    }

    fn make_instance_kind(
        _key: YuvImageKey,
        data_handle: YuvImageDataHandle,
        _prim_store: &mut PrimitiveStore,
    ) -> PrimitiveKind {
        PrimitiveKind::YuvImage {
            data_handle,
        }
    }
}

impl IsVisible for YuvImage {
    fn is_visible(&self) -> bool {
        true
    }
}

#[test]
#[cfg(target_pointer_width = "64")]
fn test_struct_sizes() {
    use std::mem;
    // The sizes of these structures are critical for performance on a number of
    // talos stress tests. If you get a failure here on CI, there's two possibilities:
    // (a) You made a structure smaller than it currently is. Great work! Update the
    //     test expectations and move on.
    // (b) You made a structure larger. This is not necessarily a problem, but should only
    //     be done with care, and after checking if talos performance regresses badly.
    assert_eq!(mem::size_of::<Image>(), 36, "Image size changed");
    assert_eq!(mem::size_of::<ImageTemplate>(), 56, "ImageTemplate size changed");
    assert_eq!(mem::size_of::<ImageKey>(), 40, "ImageKey size changed");
    assert_eq!(mem::size_of::<YuvImage>(), 32, "YuvImage size changed");
    assert_eq!(mem::size_of::<YuvImageTemplate>(), 76, "YuvImageTemplate size changed");
    assert_eq!(mem::size_of::<YuvImageKey>(), 36, "YuvImageKey size changed");
}